Amazon Animals

Question 1

Answer 1

A barracuda, or cuda for short, is a large, predatory, ray-finned fish known for its fearsome appearance and ferocious behaviour. The barracuda is a saltwater fish of the genus Sphyraena, the only genus in the family Sphyraenidae, which was named by Constantine Samuel Rafinesque in 1815.[2] It is found in tropical and subtropical oceans worldwide ranging from the eastern border of the Atlantic Ocean to the Red Sea, on its western border the Caribbean Sea, and in tropical areas of the Pacific Ocean. Barracudas reside near the top of the water and near coral reefs and sea grasses.[3] Barracudas are targeted by sport-fishing enthusiasts.

Barracuda are snake-like in appearance, with prominent, sharp-edged, fang-like teeth, much like piranha, all of different sizes, set in sockets of their large jaws. They have large, pointed heads with an underbite in many species. Their gill covers have no spines and are covered with small scales. Their two dorsal fins are widely separated, with the anterior fin having five spines, and the posterior fin having one spine and nine soft rays. The posterior dorsal fin is similar in size to the anal fin and is situated above it. The lateral line is prominent and extends straight from head to tail. The spinous dorsal fin is placed above the pelvic fins and is normally retracted in a groove. The caudal fin is moderately forked with its posterior edge double-curved and is set at the end of a stout peduncle. The pectoral fins are placed low on the sides. The swim bladder is large, allowing for minimal energy expenditure while cruising or remaining idle.[5]

In most cases, barracuda are dark gray, dark green, white, or blue on the upper body, with silvery sides and a chalky-white belly. Coloration varies somewhat between species. For some species, irregular black spots or a row of darker cross-bars occur on each side. Their fins may be yellowish or dusky. Barracudas live primarily in oceans, but certain species, such as the great barracuda, live in brackish water. Due to similarities, sometimes Barracuda is compared with freshwater Pike, though the major difference between the two is that Barracuda has two separate dorsal fins with a forked tail, unlike the freshwater pike.[6][7]

Some species grow quite large (up to 65 inches or 165 cm in length),[8] such as Sphyraena sphyraena, found in the Mediterranean Sea and eastern Atlantic; Sphyraena picudilla, ranging on the Atlantic coast of tropical America from North Carolina to Brazil and reaching Bermuda. Other barracuda species are found around the world. Examples are Sphyraena argentea, found from Puget Sound southwards to Cabo San Lucas, Sphyraena jello, from the seas of India and the Malay Peninsula and Archipelago.

Barracudas are ferocious, opportunistic predators, relying on surprise and short bursts of speed, up to 27 mph (43 km/h),[12] to overtake their prey.

Adults of most species are more or less solitary, while young and half-grown fish frequently congregate. Barracudas prey primarily on fish (which may include some as large as themselves). They kill and consume larger prey by tearing chunks out of their prey. Barracuda species are often seen competing against mackerel, needle fish and sometimes even dolphins for prey.[3]

Barracuda feed on an array of prey including fish such as jacks, grunts, groupers, snappers, small tunas, mullets, killifishes, herrings, and anchovies by simply biting them in half.[13] They also seem to consume smaller species of sustenance that are in front of them.

Barracudas are usually found swimming in saltwater searching for schools of plankton-feeding fish. Their silver and elongated bodies make them difficult for prey to detect, and even more difficult to be seen when viewing them head-on. Barracudas depend heavily on their eyesight when they are out hunting. When hunting, they tend to notice everything that has an unusual color, reflection, or movement. Once a barracuda targets an intended victim, its long tail and matching anal and dorsal fins enable it to move with swift bursts of speed to attack its prey before it can escape. Barracudas generally attack schools of fish, speeding at them head first and biting at them with their jaws. When barracudas age, they tend to swim alone. However, there are times where they tend to stay with the pack. Barracudas will sometimes swim in groups. In this case, they can relocate schools of fish into compact areas or lead them into shallow water to more easily feed on them.[citation needed]

Interactions with humans
Edit
Some species of barracuda are reputed to be dangerous to swimmers. Barracudas are scavengers, and may mistake snorkelers for large predators, following them hoping to eat the remains of their prey. Swimmers have reported being bitten by barracudas, but such incidents are rare and possibly caused by poor visibility. Large barracudas can be encountered in muddy shallows on rare occasion. Barracudas may mistake things that glint and shine for prey.[14] One incident reported a barracuda jumping out of water and injuring a kayaker,[15] but Jason Schratwieser, conservation director of the International Game Fish Association, said that the wound could have been caused by a houndfish.[16]

Barracudas are popular both as food and game fish. They are most often eaten as fillets or steaks. Larger species, such as the great barracuda, have been implicated in cases of ciguatera food poisoning.[17] Those who have been diagnosed with this type of food poisoning display symptoms of gastrointestinal discomfort, limb weakness, and an inability to differentiate hot from cold effectively.[13]

West Africans smoke them for use in soups and sauces. Smoking protects the soft flesh from disintegrating in the broth and gives it a smoky flavour.

The “Blue Barracudas” were a team on the 90’s Nickelodeon gameshow Legends of the Hidden Temple.

The barracuda prominently appeared in the 2003 Disney/Pixar animated film Finding Nemo, in the beginning of the film, when it attacks the clownfishes Marlin (Albert Brooks), Coral (Elizabeth Perkins), Nemo (Alexander Gould) and their eggs who lives in the sea anemone by the drop off in the Great Barrier Reef in Australia. Before the main titles in the film and in the 3D version release in 2012, the barracuda closes its teeth and the bottom lip is shown in the film. Nemo likely would not have survived into adulthood due to his small fin had the barracuda not eaten all other eggs. (The same barracuda also appeared as an easter egg in the 2019 Disney/Pixar animated film Toy Story 4. It was stuffed and mounted in display in the Second Chances antique store.)[citation needed]

“Barracuda” is the title of a 1977 hit song by American rock band Heart.[18]

The Pokémon Arrokuda and its evolution Barraskewda (both introduced to the franchise in Pokémon Sword and Shield) are based on the barracuda.

The Plymouth Barracuda is a two-door pony car that was manufactured by Plymouth from 1964 to 1974.

Question 2

Answer 2

Kingfishers are a family, the Alcedinidae, of small to medium-sized, brightly colored birds in the order Coraciiformes. They have a cosmopolitan distribution, with most species found in the tropical regions of Africa, Asia, and Oceania, but also can be seen in Europe. They can be found in deep forests near calm ponds and small rivers. The family contains 114 species and is divided into three subfamilies and 19 genera. All kingfishers have large heads, long, sharp, pointed bills, short legs, and stubby tails. Most species have bright plumage with only small differences between the sexes. Most species are tropical in distribution, and a slight majority are found only in forests.

They consume a wide range of prey usually caught by swooping down from a perch. While kingfishers are usually thought to live near rivers and eat fish, many species live away from water and eat small invertebrates. Like other members of their order, they nest in cavities, usually tunnels dug into the natural or artificial banks in the ground. Some kingfishers nest in arboreal termite nests. A few species, principally insular forms, are threatened with extinction. In Britain, the word “kingfisher” normally refers to the common kingfisher.

The kingfisher family Alcedinidae is in the order Coraciiformes, which also includes the motmots, bee-eaters, todies, rollers, and ground-rollers.[2] The name of the family was introduced (as Alcedia) by the French polymath Constantine Samuel Rafinesque in 1815.[3][4] It is divided into three subfamilies, the tree kingfishers (Halcyoninae), the river kingfishers (Alcedininae), and the water kingfishers (Cerylinae).[2] The name Daceloninae is sometimes used for the tree kingfisher subfamily but it was introduced by Charles Lucien Bonaparte in 1841 while Halcyoninae introduced by Nicholas Aylward Vigors in 1825 is earlier and has priority.[5] A few taxonomists elevate the three subfamilies to family status.[6][7] In spite of the word “kingfisher” in their English vernacular names, many of these birds are not specialist fish-eaters; none of the species in Halcyoninae are.[8]

The centre of kingfisher diversity is the Australasian realm, but the group originated in the Indomalayan region around 27 million years ago (Mya) and invaded the Australasian realm a number of times.[9] Fossil kingfishers have been described from Lower Eocene rocks in Wyoming and Middle Eocene rocks in Germany, around 30–40 Mya. More recent fossil kingfishers have been described in the Miocene rocks of Australia (5–25 Mya). Several fossil birds have been erroneously ascribed to the kingfishers, including Halcyornis, from the Lower Eocene rocks in Kent, which has also been considered a gull, but is now thought to have been a member of an extinct family.[10]

Amongst the three subfamilies, the Alcedininae are basal to the other two subfamilies. The few species found in the Americas, all from the subfamily Cerylinae, suggest that the sparse representation in the Western Hemisphere resulted from just two original colonising events. The subfamily is a comparatively recent split from the Halcyoninae, diversifying in the Old World as recently as the Miocene or Pliocene.[1]

The smallest species of kingfishers is the African dwarf kingfisher (Ispidina lecontei), which averages 10 cm (3.9 in) in length and between 9 and 12 g (0.32 and 0.42 oz) in weight.[11] The largest kingfisher in Africa is the giant kingfisher (Megaceryle maxima), which is 42 to 46 cm (17 to 18 in) in length and 255–426 g (9.0–15.0 oz) in weight.[12] The familiar Australian kingfisher, known as the laughing kookaburra (Dacelo novaeguineae), is the heaviest species, with females reaching nearly 500 g (18 oz) in weight.[13]

The plumage of most kingfishers is bright, with green and blue being the most common colours. The brightness of the colours is neither the product of iridescence (except in the American kingfishers) or pigments, but is instead caused by the structure of the feathers, which causes scattering of blue light (the Tyndall effect).[14] In most species, no overt differences between the sexes exist; when differences occur, they are quite small (less than 10%).[10]

The kingfishers have long, dagger-like bills. The bill is usually longer and more compressed in species that hunt fish, and shorter and more broad in species that hunt prey off the ground. The largest and most atypical bill is that of the shovel-billed kookaburra, which is used to dig through the forest floor in search of prey. They generally have short legs, although species that feed on the ground have longer tarsi. Most species have four toes, three of which are forward-pointing.

The irises of most species are dark brown. The kingfishers have excellent vision; they are capable of binocular vision and are thought in particular to have good colour vision. They have restricted movement of their eyes within the eye sockets, instead using head movements to track prey. In addition, they are capable of compensating for the refraction of water and reflection when hunting prey underwater, and are able to judge depth under water accurately. They also have nictitating membranes that cover the eyes to protect them when they hit the water; the pied kingfisher has a bony plate, which slides across the eye when it hits the water.[10]

The kingfishers have a cosmopolitan distribution, occurring throughout the world’s tropical and temperate regions. They are absent from the polar regions and some of the world’s driest deserts. Several species have reached islands groups, particularly those in the south and east Pacific Ocean. The Old World tropics and Australasia are the core areas for this group. Europe and North America north of Mexico are very poorly represented, with only one common kingfisher (common kingfisher and belted kingfisher, respectively), and two uncommon or very local species each: (ringed kingfisher and green kingfisher in the southwestern United States, pied kingfisher and white-throated kingfisher in southeastern Europe). The six species occurring in the Americas are four closely related green kingfishers in the genus Chloroceryle and two large crested kingfishers in the genus Megaceryle. Even tropical South America has only five species plus the wintering belted kingfisher. In comparison, the African country of the Gambia has eight resident species in its 120-by-20-mile (193 by 32 km) area.[10]

Individual species may have massive ranges, like the common kingfisher, which ranges from Ireland across Europe, North Africa, and Asia as far as the Solomon Islands in Australasia, or the pied kingfisher, which has a widespread distribution across Africa and Asia. Other species have much smaller ranges, particularly insular species which are endemic to single small islands. The Kofiau paradise kingfisher is restricted to the island of Kofiau off New Guinea.[10]

Kingfishers occupy a wide range of habitats. While they are often associated with rivers and lakes, over half the world’s species are found in forests and forested streams. They also occupy a wide range of other habitats. The red-backed kingfisher of Australia lives in the driest deserts, although kingfishers are absent from other dry deserts like the Sahara. Other species live high in mountains, or in open woodland, and a number of species live on tropical coral atolls. Numerous species have adapted to human-modified habitats, particularly those adapted to woodlands, and may be found in cultivated and agricultural areas, as well as parks and gardens in towns and cities.[10]

Kingfishers feed on a wide variety of prey. They are most famous for hunting and eating fish, and some species do specialise in catching fish, but other species take crustaceans, frogs and other amphibians, annelid worms, molluscs, insects, spiders, centipedes, reptiles (including snakes), and even birds and mammals. Individual species may specialise in a few items or take a wide variety of prey, and for species with large global distributions, different populations may have different diets. Woodland and forest kingfishers take mainly insects, particularly grasshoppers, whereas the water kingfishers are more specialised in taking fish. The red-backed kingfisher has been observed hammering into the mud nests of fairy martins to feed on their nestlings.[15] Kingfishers usually hunt from an exposed perch; when a prey item is observed, the kingfisher swoops down to snatch it, then returns to the perch. Kingfishers of all three families beat larger prey on a perch to kill the prey and to dislodge or break protective spines and bones. Having beaten the prey, it is manipulated and then swallowed.[10] Sometimes, a pellet of bones, scales, and other indigestible debris is coughed up.[16] The shovel-billed kookaburra uses its massive, wide bill as a shovel to dig for worms in soft mud.

Breeding
Edit
Kingfishers are territorial, some species defending their territories vigorously. They are generally monogamous, although cooperative breeding has been observed in some species and is quite common in others,[10] for example the laughing kookaburra, where helpers aid the dominant breeding pair in raising the young.[17]

Like all Coraciiformes, the kingfishers are cavity nesters, as well as tree nesters, with most species nesting in holes dug in the ground. These holes are usually in earth banks on the sides of rivers, lakes or man-made ditches. Some species may nest in holes in trees, the earth clinging to the roots of an uprooted tree, or arboreal nests of termites (termitarium). These termite nests are common in forest species. The nests take the form of a small chamber at the end of a tunnel. Nest-digging duties are shared between the genders. During the initial excavations, the bird may fly at the chosen site with considerable force, and birds have injured themselves fatally while doing this. The length of the tunnels varies by species and location; nests in termitaria are necessarily much shorter than those dug into the earth, and nests in harder substrates are shorter than those in soft soil or sand. The longest tunnels recorded are those of the giant kingfisher, which have been found to be 8.5 m (28 ft) long.[10]

The eggs of kingfishers are invariably white. The typical clutch size varies by species; some of the very large and very small species lay as few as two eggs per clutch, whereas others may lay 10 eggs, the typical is around three to six eggs. Both sexes incubate the eggs. The offspring of the kingfisher usually stay with the parents for 3–4 months.[10]

Kingfishers are generally shy birds, but in spite of this, they feature heavily in human culture, generally due to the large head supporting its powerful mouth, their bright plumage, or some species’ interesting behavior.

For the Dusun people of Borneo, the Oriental dwarf kingfisher is considered a bad omen, and warriors who see one on the way to battle should return home. Another Bornean tribe considers the banded kingfisher an omen bird, albeit generally a good omen.[10]

The sacred kingfisher, along with other Pacific kingfishers, was venerated by the Polynesians, who believed it had control over the seas and waves.

Modern taxonomy also refers to the winds and sea in naming kingfishers after a classical Greek myth. The first pair of the mythical-bird Halcyon (kingfishers) were created from a marriage of Alcyone and Ceyx. As gods, they lived the sacrilege of referring to themselves as Zeus and Hera. They died for this, but the other gods, in an act of compassion, made them into birds, thus restoring them to their original seaside habitat. In addition, special “halcyon days” were granted. These are the seven days on either side of the winter solstice when storms shall never again occur for them. The Halcyon birds’ “days” were for caring for the winter-hatched clutch (or brood), but the phrase “Halcyon days” also refers specifically to an idyllic time in the past, or in general to a peaceful time.

Various kinds of kingfishers and human cultural artifacts are named after the couple, in reference to this metamorphosis myth:

The genus Ceyx (within the river kingfishers family) is named after him.
The kingfisher subfamily Halcyoninae (tree kingfishers) is named after his wife, as is the genus Halcyon.
The belted kingfisher’s specific name (Megaceryle alcyon) also references her name.
Not all the kingfishers are named in this way. The etymology of kingfisher (Alcedo atthis) is obscure; the term comes from “king’s fisher”, but why that name was applied is not known.[19]

Question 3

Answer 3

Poison dart frog (also known as dart-poison frog, poison frog or formerly known as poison arrow frog) is the common name of a group of frogs in the family Dendrobatidae which are native to tropical Central and South America.[2] These species are diurnal and often have brightly colored bodies. This bright coloration is correlated with the toxicity of the species, making them aposematic. Some species of the family Dendrobatidae exhibit extremely bright coloration along with high toxicity, while others have cryptic coloration with minimal to no amount of observed toxicity.[3] The species that have great toxicity derive this feature from their diet of ants, mites and termites.[3][4] However, other species that exhibit cryptic coloration, and low to no amounts of toxicity, eat a much larger variety of prey.[4] Many species of this family are threatened due to human infrastructure encroaching on their habitats.

These amphibians are often called “dart frogs” due to the Native Americans’ use of their toxic secretions to poison the tips of blowdarts. However, out of over 170 species, only four have been documented as being used for this purpose (curare plants are more commonly used for in Native American darts) all of which come from the genus Phyllobates, which is characterized by the relatively large size and high levels of toxicity of its members.[5][6]

Most species of poison dart frogs are small, sometimes less than 1.5 cm (0.59 in) in adult length, although a few grow up to 6 cm (2.4 in) in length. They weigh 1 oz. on average.[7] Most poison dart frogs are brightly colored, displaying aposematic patterns to warn potential predators. Their bright coloration is associated with their toxicity and levels of alkaloids. For example, frogs of the genus Dendrobates have high levels of alkaloids, whereas Colostethus species are cryptically colored and are not toxic.[4]

Poison dart frogs are an example of an aposematic organism. Their bright coloration advertises unpalatability to potential predators. Aposematism is currently thought to have originated at least four times within the poison dart family according to phylogenetic trees, and dendrobatid frogs have since undergone dramatic divergences – both interspecific and intraspecific – in their aposematic coloration. This is surprising given the frequency-dependent nature of this type of defense mechanism.[3][8]

Adult frogs lay their eggs in moist places, including on leaves, in plants, among exposed roots, and elsewhere. Once the eggs hatch, the adult piggybacks the tadpoles, one at a time, to suitable water: either a pool, or the water gathered in the throat of bromeliads or other plants. The tadpoles remain there until they metamorphose, in some species fed by unfertilized eggs laid at regular intervals by the mother.[9]

Poison dart frogs are endemic to humid, tropical environments of Central and South America.[5] These frogs are generally found in tropical rainforests, including in Bolivia, Costa Rica, Brazil, Colombia, Ecuador, Venezuela, Suriname, French Guiana, Peru, Panama, Guyana, Nicaragua, and Hawaii (introduced).[5][10]

Natural habitats include moist, lowland forests (subtropical and tropical), high-altitude shrubland (subtropical and tropical), moist montanes and rivers (subtropical and tropical), freshwater marshes, intermittent freshwater marshes, lakes and swamps. Other species can be found in seasonally wet or flooded lowland grassland, arable land, pastureland, rural gardens, plantations, moist savanna and heavily degraded former forest. Premontane forests and rocky areas have also been known to hold frogs. Dendrobatids tend to live on or close to the ground, but also in trees as much as 10 m (33 ft) from the ground.[11]

Many species of poison dart frogs are dedicated parents. Many poison dart frogs in the genera Oophaga and Ranitomeya carry their newly hatched tadpoles into the canopy; the tadpoles stick to the mucus on the backs of their parents. Once in the upper reaches of the rainforest trees, the parents deposit their young in the pools of water that accumulate in epiphytic plants, such as bromeliads. The tadpoles feed on invertebrates in their nursery, and their mother will even supplement their diet by depositing eggs into the water. Other poison frogs lay their eggs on the forest floor, hidden beneath the leaf litter. Poison frogs fertilize their eggs externally; the female lays a cluster of eggs and a male fertilizes them afterward, in the same manner as most fish. Poison frogs can often be observed clutching each other, similar to the manner most frogs copulate. However, these demonstrations are actually territorial wrestling matches. Both males and females frequently engage in disputes over territory. A male will fight for the most prominent roosts from which to broadcast his mating call; females fight over desirable nests, and even invade the nests of other females to devour competitor’s eggs.[12]

The operational sex ratio in the poison dart frog family is mostly female biased. This leads to a few characteristic behaviors and traits found in organisms with an uneven sex ratio. In general, females have a choice of mate. In turn, males show brighter coloration, are territorial, and are aggressive toward other males. Females select mates based on coloration (mainly dorsal), calling perch location, and territory.[13]

The chemical defense mechanisms of the Dendrobates family is the result of endogenous means.[22] As explained before, essentially this means that its ability to defend through chemical violence and defense is a means that has come through the consumption of a particular diet. In fact when captive raised species were raised they exhibited non-detectable levels of toxins whereas the wild-caught species did as a result of their calcium and vitamin Drosophila and cricket diet. The secretion of these chemicals is released by the granular glands of the frog.[22] The discharge happens as a result of acetylcholine being released into the body which triggers the sympathetic or parasympathetic system depending on the species which leads to the chemical being secreted.[22] The chemical secreted by the Dndrobatid family of frogs is said to be incredibly unique as some species secrete alkaloids that consist of a greatly different and unique chemical structure and toxicity.[22] It has been suggested that initially the granular glands were solely responsible for the production and synthesis of the diverse toxins a part of the different species of Dendrobates, then through evolution the glands were adapted to also be responsible for storage, and then finally even the secretion of them upon triggering.[22]

Many poison dart frogs secrete lipophilic alkaloid toxins such as allopumiliotoxin 267A, batrachotoxin, epibatidine, histrionicotoxin, and pumiliotoxin 251D through their skin. Alkaloids in the skin glands of poison frogs serve as a chemical defense against predation, and they are therefore able to be active alongside potential predators during the day. About 28 structural classes of alkaloids are known in poison frogs.[5][23] The most toxic of poison dart frog species is Phyllobates terribilis. It is argued that dart frogs do not synthesize their poisons, but sequester the chemicals from arthropod prey items, such as ants, centipedes and mites – the diet-toxicity hypothesis.[24][25] Because of this, captive-bred animals do not possess significant levels of toxins as they are reared on diets that do not contain the alkaloids sequestered by wild populations. In fact, new studies suggest that the maternal frogs of some species lay unfertilized eggs, which are laced with trace amounts of alkaloids, to feed the tadpoles.[26] This behavior shows that the poisons are introduced from a very young age. Nonetheless, the captive-bred frogs retain the ability to accumulate alkaloids when they are once again provided an alkaloidal diet.[27] Despite the toxins used by some poison dart frogs, some predators have developed the ability to withstand them. One is the snake Erythrolamprus epinephalus, which has developed immunity to the poison.[28]

Chemicals extracted from the skin of Epipedobates tricolor may have medicinal value. Scientists use this poison to make a painkiller.[29] One such chemical is a painkiller 200 times as potent as morphine, called epibatidine; however, the therapeutic dose is very close to the fatal dose.[30] A derivative ABT-594 developed by Abbott Laboratories, called Tebanicline got as far as Phase II trials in humans,[31] but was dropped from further development due to dangerous gastrointestinal side effects.[32] Secretions from dendrobatids are also showing promise as muscle relaxants, heart stimulants and appetite suppressants.[33] The most poisonous of these frogs, the golden poison frog (Phyllobates terribilis), has enough toxin on average to kill ten to twenty men or about twenty thousand mice.[34] Most other dendrobatids, while colorful and toxic enough to discourage predation, pose far less risk to humans or other large animals.

Ranitomeya amazonica
Conspicuousness
Conspicuous coloration in these frogs is further associated with diet specialization, body mass, aerobic capacity, and chemical defense.[8] Conspicuousness and toxicity may be inversely related, as polymorphic poison dart frogs that are less conspicuous are more toxic than the brightest and most conspicuous species.[35] Energetic costs of producing toxins and bright color pigments lead to potential trade-offs between toxicity and bright coloration,[36] and prey with strong secondary defenses have less to gain from costly signaling. Therefore, prey populations that are more toxic are predicted to manifest less bright signals, opposing the classical view that increased conspicuousness always evolves with increased toxicity.[37]

Aposematism
Skin toxicity evolved alongside bright coloration,[38] perhaps preceding it.[3] Toxicity may have relied on a shift in diet to alkaloid-rich arthropods,[24] which likely occurred at least four times among the dendrobatids.[24] Either aposematism and aerobic capacity preceded greater resource gathering, making it easier for frogs to go out and gather the ants and mites required for diet specialization, contrary to classical aposematic theory, which assumes that toxicity from diet arises before signaling. Alternatively, diet specialization preceded higher aerobic capacity, and aposematism evolved to allow dendrobatids to gather resources without predation.[8] Prey mobility could also explain the initial development of aposematic signaling. If prey have characteristics that make them more exposed to predators, such as when some dendrobatids shifted from nocturnal to diurnal behavior, then they have more reason to develop aposematism.[3] After the switch, the frogs had greater ecological opportunities, causing dietary specialization to arise. Thus, aposematism is not merely a signaling system, but a way for organisms to gain greater access to resources and increase their reproductive success.[39]

Other factors
Dietary conservatism (long-term neophobia) in predators could facilitate the evolution of warning coloration, if predators avoid novel morphs for a long enough period of time.[40] Another possibility is genetic drift, the so-called gradual-change hypothesis, which could strengthen weak pre-existing aposematism.[41]

Sexual selection may have played a role in the diversification of skin color and pattern in poison frogs.[42][43][44][45] With female preferences in play, male coloration could evolve rapidly. Sexual selection is influenced by many things. The parental investment may shed some light on the evolution of coloration in relation to female choice. In Oophaga pumilio, the female provides care for the offspring for several weeks whereas the males provides care for a few days, implying a strong female preference. Sexual selection increases phenotypic variation drastically. In populations of O. pumilio that participated in sexual selection, the phenotypic polymorphism was evident.[46] The lack of sexual dimorphism in some dendrobatid populations however suggests that sexual selection is not a valid explanation.[47]

Functional trade-offs are seen in poison frog defense mechanisms relating to toxin resistance. Poison dart frogs containing epibatidine have undergone a 3 amino acid mutation on receptors of the body, allowing the frog to be resistant to its own poison. Epibatidine-producing frogs have evolved poison resistance of body receptors independently three times. This target-site insensitivity to the potent toxin epibatidine on nicotinic acetylcholine receptors provides a toxin resistance while reducing the affinity of acetylcholine binding.[48]

All species of poison dart frogs are Neotropical in origin. Wild-caught specimens can maintain toxicity for some time (this can be obtained through a form of bioaccumulation), so appropriate care should be taken when handling them.[49] While scientific study on the lifespan of poison dart frogs is scant, retagging frequencies indicate it can range from one to three years in the wild.[50] However, these frogs typically live for much longer than that in captivity, having been reported to live as long as 25 years. These claims also seem to be questionable, since many of the larger species take a year or more to mature, and Phyllobates species can take more than two years. In captivity, most species thrive where the humidity is kept constant at 80 to 100% and where the temperature is around 72 °F (22 °C) to 80 °F (27 °C) during the day and no lower than 60 °F (16 °C) to 65 °F (18 °C) at night. Some species tolerate lower temperatures better than others.[citation needed]

The poison dart frog is known for its aggressive and predatory behavior. As tadpoles, the individuals of the genus Dendrobates are said to exhibit some unique cannibalistic tendencies, along with many other forms of predatory behavior.[56] Dendrobates tadpoles that either consumed three or more conspecific tadpoles and/or relatively large larvae of a specific species of mosquito by the name of Trichoprosopon digitatum common in their environment led them to having a much higher growth rate and typically lived much longer lives.[56] Reasons for this behavior could be that predation and aggression was selected for and favored for a few reasons. One reason is to eliminate predators, and the second reason is that it serves as a source of food in habitats that were low in resources. This predation could have evolved over time and led to cannibalism as another form of predatory behavior that had benefitted individuals survival fitness.[56] However one observation has been noted in the general characteristic of Dendrobate tadpoles including D. arboreus, D. granuliferus, D. lehmanni, D. occultator, D. pumilio, D. Speciosus, and many other Dendrobates species is that they have reduced mouth parts as young tadpoles which limits their consumption typically to unfertilized eggs only.[56] Thus, it can be assumed that the cannibalistic tendencies of Dendrobates is limited to their lifetime as a tadpole and does not cross over into their adult life.

Dendrobates are a family of species very well known for their territorial and aggressive behavior not only as tadpoles, but as adults too. These aggression behaviors were not only limited to males, as many female Dendrobates also are known to defend their own native territory very aggressively.[57] These areas that were being defended aggressively by Dendrobate were typically found to be regions that served as male calling sites.[57] In fact, the males were seen wrestling with intruders of their territory in order to defend their calling sites as well as their vegetation.[57] The different ways in which Dendrobates defended their own territories included physical combat and aggression. While vocalization and various behavioral displays served as a way of exhibiting one’s strength or fitness, territorial disputes and fights led to physical combat and aggression at times too.[57] Physical violence and aggression is particularly common at times of calling. If it was seen that an intruder was making calls in the territory of a Dendrobate frog then the resident frog would attempt to eliminate the competition to claim the territory and the females in it to himself.[57] The resident frog would initially try to make its presence known by the means of vocalization and various behavioral displays as a way to exert dominance.[57] If this did not scare away the intruder, then the resident frog would move towards the intruder and strike them.[57] This encounter would immediately escalate into a full on fight where both are striking each other and grasping each other’s limbs.[57] Similarly, the females also often would get into fights and display aggressive behaviors in disputes over territory or a mating conflict. It was also observed that females who were going after the same male, after hearing their call, would chase each other down and wrestle to fight for the male.[58] After a female courts with a male, they are also very likely to exhibit aggressive behavior towards any females that approach that male.[58] Both the males and females bought their own respective sexes for each other in a fairly similar fashion.[58]

Observations of the Dendrobates family suggest that males of the species would typically make their mating call in morning between the times of 6:30am to 11:30am.[57] The calling would typically come from a place of elevation from various pieces of nature. The males would usually be on average one meter above the ground on limbs, trunks, and stems, or logs of trees so that their voice traveled further as well as the fact that it would help themselves be seen.[57] The calls were signaled towards the stream as the females typically were in that area.[57] Each male typically had their own region in which they only made calls from, and typically an individual would repeat their calls from the same spot during a mating season.[57] After the call is received, the female makes its way to the male, and fertilization occurred in a few instances.[57] This observed fertilization was not accomplished through amplexus.[57] Initiation and interaction during courtship typically were the result of active females rather than males.[58] The females stroked, climbed on, and jumped on the other in tactile courtship, and were by far the more active sex.[58] The duration of courtship in poison frogs is long and females could even reject males even after an entire day of active following which was found to occur in a few instances.[59] In the majority of cases, the males in fact chose the oviposition site and led the way and females usually followed the male to the site.[57] In some Dendrodates species, such as strawberry poison frog, visual cues under high light intensity were also used to identify individuals from the same population.[59] Different species use different cues to identify individuals from their same population during the time of mating and courtship.

The diet of the Dendrobates is unique and vital in giving this family of frogs characteristics that are distinct from the rest. The diet of Dendrobates is what gives it the alkaloids that are found in its skin.[22] This unique skin color and pigmentation and ability to transform color is an distinct feature that finds its basis in its diet. The diet is also what allows this family of frogs to have a defense mechanism such as poison, which is why it’s commonly referred to as the poison dart frog.[22] Both skin alkaloids and venoms and toxins are substances that can be from endogenous sources.[22] Endogenous sources essentially means that the individual themselves is producing or synthesizing those substances on their own, or they can be obtained through exogenous sources like consumption.[22] Researchers have studied these characteristics and have formed the diet-toxicity hypothesis which just implies that they believe that the diet of these Dendrobates is what gives them their toxicity and skin alkaloids.[22] The data from numerous studies has led to the conclusions that there are direct correlations present between the frog’s diet and its skin alkaloids that act as evidence to prove the diet-toxicity hypothesis .[22] The diet that is responsible for these characteristics consists primarily of small and leaf-litter arthropods found in its general habitat, typically ants.[22] Their diet, however, is typically separated into two distinct categories.[60] The first is the primary portion of Dendrobates’ diet which include prey that are slow-moving, large in number, and small in size.[60] This typically consists of ants, while also including mites, small beetles, and minor litter-dwelling taxa.[60] The second category of prey are much rarer finds and are much larger in body size, and they tend to have high palatability and mobility.[60] These typically consist of you orthopteroids, lepidopteran larvae, as well as spiders.[60] The natural diet of an individual Dendrobate depends on its species, prey abundance in its location, as well as many other factors. The available species present in the individual’s enivornment can influence its diet vastly. Frogs of one species can specialize in preying on one particular prey, whereas another can focus on a different type of prey. The preference is one that depends on various factors that are calculated and decided upon as the most beneficial for one’s own fitness.

Typically in many species the larger portion of parental investment falls on the shoulders of the female sex, whereas the male sex has a much smaller portion.[58] However, it has been studied that in the family of Dendrobates, many of the species exhibit sex role reversal in which the females are competing for a limited number of males and the males are the choosers and their parental investment is much larger than the females.[58] This theory also says that the female will typically produce eggs at an exceedingly fast rate that the males cannot possibly take full care of them which then leads to some of the males becoming unreceptive.[58] Dendrobates also exhibit the parental quality hypothesis. The parental quality hypothesis is where the females mating with the males try to ensure that their male mates with as few individuals as possible so that their number of offspring is limited, and thus each individual offspring receives a larger portion of care, attention, and resources.[58] However, this creates an interesting dynamic of balance as there is a limited number of males available, and with many females competing for a limited number of males for courtship this makes it difficult ot limit the number of individuals a male mates with. Whereas in many species, the competition is flipped in that the competition is prominent among the males, among the Dendrobates it is the opposite as the females seem to have a great deal of competition among themselves for males. Females will even take the drastic measures and resort to the destroying of other female’s eggs in order to make sure that the male they mated with is receptive and that it scares the male from mating with other females.[58]

Question 4

Answer 4

Squirrel monkeys are New World monkeys of the genus Saimiri. Saimiri is the only genus in the subfamily Saimirinae. The name of the genus is of Tupi origin (sai-mirím or çai-mbirín, with sai meaning ‘monkey’ and mirím meaning ‘small’)[3] and was also used as an English name by early researchers.[4][5]

Squirrel monkeys live in the tropical forests of Central and South America in the canopy layer. Most species have parapatric or allopatric ranges in the Amazon, while S. oerstedii is found disjunctly in Costa Rica and Panama.

There are two main groups of squirrel monkeys recognized. They are differentiated based on the shape of the white coloration above the eyes. In total there are 5 recognized species.[6][7] Squirrel monkeys have short and close fur colored black at the shoulders, yellow or orange fur along the back and extremities, and white on the face.[8]

Squirrel monkeys have determined breeding seasons which involve large fluctuations in hormones and there is evidence of sexual dimorphism in males.[9]

Squirrel monkeys can only sweat through the palms of their hands and feet. This can have the effect of making their hands and feet feel damp to the touch. Squirrel monkeys must make use of other thermoregulation techniques such as behavioral changes and urine washing. [10] These monkeys live in habitats of high temperatures and high humidity, making it essential for them to maintain proper osmoregulation if conditions pass certain thresholds.[11] Color vision studies have also been performed on squirrel monkeys for the purpose of better understanding vision ailments in humans.[12]

The common squirrel monkey is commonly captured for the pet trade and for medical research,[13] but it is not threatened. Two squirrel monkey species are endangered: the Central American squirrel monkey and the black squirrel monkey are listed as vulnerable by the IUCN.[6][14]

Taxonomy
Edit
Until 1984, all South American squirrel monkeys were considered part of a single widespread species, and many zoologists considered the Central American squirrel monkey to be a member of that single species as well.[1][7] The two main groups currently recognized can be separated by the white above the eyes; it is shaped as a Gothic (“pointed”) arch in the S. sciureus group, while it is shaped as a Roman (“rounded”) arch in the S. boliviensis group.[15] Mammal Species of the World (2005) recognized 5 species.[1]

Subsequent taxonomic research has recognized Saimiri sciureus cassiquiarensis as a separate species Saimiri cassiquiarensis, and also recognized an additional species, Collins’ squirrel monkey Saimiri collinsi that had previously been considered to be within S. sciureus.[16] Some more recent taxonomies also recognize Saimiri sciureus macrodon as a separate species Saimiri macrodon, but others recognize S. macrodon to be a synonym of Saimiri cassiquiarensis.[17][18][19][20]

Evolution
Edit
The crown group of the extant squirrel monkeys appears to have diverged around 1.5 million years ago.[21] Diversification of squirrel monkey species appears to have occurred during the Pleistocene Epoch, likely due to climatic changes associated with interglacial periods in South America at the time. The origin of squirrel monkeys in Central America is unclear, but a possible hypothesis is human transport. More genetic work needs to be done on the subject to reveal a true answer.[21]S. boliviensis appears to be the first diverging species in the group. S. oerstedii and S. s. sciureus, are sister species. S. s. macrodon is the sister species to the S. oerstedii / S. s. sciureus clade.[clarification needed]

A squirrel monkey’s fur is short and close, coloured black at the shoulders and yellowish orange on its back and extremities. The upper parts of their heads are hairy. This black-and-white face gives them the name “death’s head monkey” in several Germanic languages (e.g., German Totenkopfaffen, Swedish dödskalleapor, Dutch doodshoofdaapjes) and Slovenian (smrtoglavka).

Squirrel monkeys grow from 25 to 35 centimetres (9.8 to 13.8 in) long, plus a 35 to 42 centimetres (14 to 17 in) tail. Male squirrel monkeys weigh 750 to 1,100 grams (26 to 39 oz). Females weigh 500 to 750 grams (18 to 26 oz). Both males and females are equipped with long and hairy tails, flat nails, and pointed claws.[8]

Female squirrel monkeys have pseudo-penises, which they use to display dominance over smaller monkeys, in much the same way that the male squirrel monkeys display their dominance.[citation needed]

Like most of their New World monkey relatives, squirrel monkeys are diurnal and arboreal. Unlike other New World monkeys, their tail is not used for climbing but as a kind of “balancing pole” and also as a tool. Their movements in the branches can be very rapid.

Squirrel monkeys live together in multi-male/multi-female groups with up to 500 members. These large groups, however, can occasionally break into smaller troupes. The groups have a number of vocal calls, including warning sounds to protect the group from large falcons, which are a natural threat. Their small body size also makes them susceptible to predators such as snakes and felids. For marking territory, squirrel monkeys rub their tail and their skin with their own urine.

Squirrel monkeys are omnivores, eating primarily fruits and insects. Occasionally, they also eat seeds, leaves, flowers, buds, nuts, and eggs.

Reproduction
Edit
Squirrel monkey mating is subject to seasonal influences. Squirrel monkeys reach sexual maturity at ages of 2–2.5 years for females and age 3.5–4 years for males. Females give birth to young during the rainy season, after a 150- to 170-day gestation. Only the mothers care for the young. Saimiri oerstedti are weaned by 4 months of age, while S. boliviensis are not fully weaned until 18 months old. Squirrel monkeys live to about 15 years old in the wild, and over 20 years in captivity. Menopause in females probably occurs in the mid-teens.[22] Studies show that Saimiri collinsi time the weaning of their young with the period of time when there will be maximum fruit availability in the environment. This reduces the energetic struggles that newly weaned juveniles will face when transitioning from a milk diet where they are dependent on their mother for food to a more diverse diet where they have to forage for food.[23] There is evidence that squirrel monkeys show sexual dimorphism during the breeding season. In the months leading up to breeding and in the months of breeding, sexually mature adult males have been recorded to increase in size by significant amounts relative to females. These size changes are caused by seasonal fluctuations in androgen hormones synthesized in the hypothalamus, pituitary, adrenal and gonadal axes. The fluctuations include increases in the concentrations of testosterone, androstenedione, and dehydroepiandrosterone levels in sexually mature males during the breeding season, peaking in January. Following the breeding season, these androgen concentrations drop.[9] The evolutionary reasoning for these size changes in sexually mature males is suggested to be both intra-sexual selection among males and also female choice selection, as the larger males are more likely to be preferred by females and partake in more copulations. There is not clear evidence yet as to why females choose larger males, but a leading hypothesis is that the larger males are more likely to have better vigilance for their young.[24]

Thermoregulation
Edit
Squirrel monkeys can only sweat through the palms of their hands and the soles of their feet. Sweating in these areas alone does not provide enough cooling for the monkeys to survive in the high temperature environments of South and Central America, requiring them to use other methods to thermoregulate. They will use behavioral tactics such as seeking out shaded areas sheltered from the sun and also make use of postural changes to better dissipate heat from their body. They will also make use of a technique to maximize evaporative cooling known as urine washing. The monkeys will urinate on their hands and rub the urine over the soles of their feet. The urine is then evaporated off the body in a cooling process. Studies have shown this behavior to be maximized during times of high temperature, highlighting its importance as a thermoregulatory behavior.[10]

Osmoregulation
Edit
Squirrel monkeys are subject to both high temperatures and high humidity in their natural habitat. The humidity can range from 70% saturation in the ‘dry’ season up to 90% in the ‘wet’ season. Squirrel monkeys are able to tolerate up to 75% humidity with small adjustments in behavior and physiology that increase in significance as the humidity goes up. When reaching approximately 95% humidity, the monkeys have more drastic changes in osmoregulation in order to maintain homeostasis. As evaporative water loss decreases at these high levels of saturation, the monkeys will take in less water and create a more concentrated urine in order to maintain proper ion and water levels inside the body.[11]

Cooperation Studies
Edit
Cooperation is largely evident in human primates. Squirrel monkeys do not often display cooperation in the wild, while many other nonhuman primates do. Studies have been done to suggest that female squirrel monkeys show disadvantageous inequity aversion as it pertains to food rewards. However, the same could not be said for male squirrel monkeys. More studies need to be done on squirrel monkey behavior to yield more information regarding why squirrel monkeys rarely show cooperation and if disadvantageous inequity aversion is a relevant factor.[25]

Colour vision
Edit
See also: Evolution of colour vision in primates
Colour vision in squirrel monkeys has been extensively studied as a stand-in for human ailments.[12] In humans, two genes for colour vision are found on the X chromosome. Typically, one gene (OPN1LW) produces a pigment that is most sensitive to the 564 nm wavelength, while the other gene (OPN1MW) produces a pigment most sensitive to 534 nm. In squirrel monkeys, there is only one gene on the X chromosome but it exists in three varieties: one is most sensitive to 538 nm, one to 551 nm, and one to 561 nm. Since males have only one X chromosome, they are dichromatic, although with different sensitivities. Females have two X chromosomes, so some of them can have copies of two different alleles. The three alleles seem to be equally common, leading to one-third of females being dichromatic, while two-thirds are trichromatic.[26] Recently, gene therapy has given the human OPN1LW gene to adult male squirrel monkeys, producing behaviour consistent with trichromatic colour vision.[12]

Question 5

Answer 5

Sardine” and “pilchard” are common names for various species of small, oily forage fish in the herring family Clupeidae.[2] The term “sardine” was first used in English during the early 15th century, a folk etymology says it comes from the Italian island of Sardinia, around which sardines were once supposedly abundant.[3][4][5]

The terms “sardine” and “pilchard” are not precise, and what is meant depends on the region. The United Kingdom’s Sea Fish Industry Authority, for example, classifies sardines as young pilchards.[6] One criterion suggests fish shorter in length than 15 cm (6 in) are sardines, and larger fish are pilchards.[7]

The FAO/WHO Codex standard for canned sardines cites 21 species that may be classed as sardines.[8] FishBase, a comprehensive database of information about fish, calls at least six species “pilchard”, over a dozen just “sardine”, and many more with the two basic names qualified by various adjectives.

‘Sardine’ first appeared in English in the 15th century, a loanword from French sardine, derived from Latin sardina, from Ancient Greek σαρδίνη (sardínē) or σαρδῖνος (sardínos),[9] said to be from the Greek “Sardò” (Σαρδώ), indicating the island of Sardinia. Athenaios quotes a fragmentary passage from Aristotle mentioning the fish sardinos, referring to the sardine or pilchard.[10] However, Sardinia is about 1,300 km (810 mi) distant from Athens; Ernest Klein in his Etymological Dictionary of the English Language (1971) writes, “It is hardly probable that the Greeks would have obtained fish from so far as Sardinia at a time relatively so early as that of Aristotle.”[11]

The flesh of some sardines or pilchards is a reddish-brown colour similar to some varieties of red sardonyx or sardine stone; this word derives from σαρδῖον (sardion) with a root meaning ‘red’ and (according to Pliny) possibly cognate with Sardis, the capital of ancient Lydia (now western Turkey) where it was obtained. However, the name may refer to the reddish-pink colour of the gemstone sard (or carnelian) known to the ancients.[12][13]

The phrase “packed like sardines” (in a tin) is recorded from 1911.[11] The phrase “…packed up like sardines…” appears in The Mirror of Literature, Amusement, and Instruction from 1841,[14] and is a translation of “…encaissés comme des sardines” which appears in La Femme, le mari, et l’amant from 1829.[15] Other early appearances of the idiom are “… packed together…like sardines in a tin-box” (1845),[16] and “…packed…like sardines in a can…” (1854).[17]

Sardines feed almost exclusively on zooplankton, “animal plankton”, and congregate wherever this is abundant.

Typically, sardines are caught with encircling nets, particularly purse seines. Many modifications of encircling nets are used, including traps or fishing weirs. The latter are stationary enclosures composed of stakes into which schools of sardines are diverted as they swim along the coast. The fish are caught mainly at night, when they approach the surface to feed on plankton. After harvesting, the fish are submerged in brine while they are transported to shore.

Sardines are commercially fished for a variety of uses: for bait; for immediate consumption; for drying, salting, or smoking; and for reduction into fish meal or oil. The chief use of sardines is for human consumption, but fish meal is used as animal feed, while sardine oil has many uses, including the manufacture of paint, varnish, and linoleum.

Sardines are commonly consumed by humans. Fresh sardines are often grilled, pickled, smoked, or preserved in cans.

Sardines are rich in vitamins and minerals.[69] A small serving of sardines once a day can provide 13% of vitamin B2; roughly one-quarter of niacin; and about 150% of the recommended daily value of vitamin B12. All B vitamins help to support proper nervous system function and are used for energy metabolism, or converting food into energy.[70] Also, sardines are high in the major minerals such as phosphorus, calcium, and potassium, and some trace minerals including iron and selenium.

Sardines are also a natural source of marine omega-3 fatty acids, which may reduce the occurrence of cardiovascular disease.[71] Regular consumption of omega-3 fatty acids may reduce the likelihood of developing Alzheimer’s disease.[72] These fatty acids can also lower blood sugar levels.[73] They are also a good source of vitamin D,[74] calcium, vitamin B12,[75][76] and protein.

Because they are low in the food chain, sardines are very low in contaminants, such as mercury, relative to other fish commonly eaten by humans.[77]

History of sardine fishing in the UK
Edit
Pilchard fishing and processing became a thriving industry in Cornwall, England from around 1750 to around 1880, after which it went into decline. Catches varied from year to year, and in 1871, the catch was 47,000 hogsheads, while in 1877, only 9,477 hogsheads. A hogshead contained 2,300 to 4,000 pilchards, and when filled with pressed pilchards, weighed 476 lbs. The pilchards were mostly exported to Roman Catholic countries such as Italy and Spain, where they are known as fermades. The chief market for the oil was Bristol, where it was used on machinery.[78]

Since 1997, sardines from Cornwall have been sold as “Cornish sardines”, and since March 2010, under EU law, Cornish sardines have Protected Geographical Status.[79] The industry has featured in numerous works of art, particularly by Stanhope Forbes and other Newlyn School artists.

The traditional “Toast to Pilchards” refers to the lucrative export of the fish to Catholic Europe:

Here’s health to the Pope, may he live to repent
And add just six months to the term of his Lent
And tell all his vassals from Rome to the Poles,
There’s nothing like pilchards for saving their souls![80]
History of sardine fishing in the United States
Edit
In the United States, the sardine canning industry peaked in the 1950s. Since then, the industry has been on the decline. The canneries in Monterey Bay, in what was known as Cannery Row in Monterey County, California (where John Steinbeck’s novel of the same name was set), failed in the mid-1950s. The last large sardine cannery in the United States, the Stinson Seafood plant in Prospect Harbor, Maine, closed its doors on 15 April 2010 after 135 years in operation.[81]

In April 2015 the Pacific Fishery Management Council voted to direct NOAA Fisheries Service to halt the current commercial season in Oregon, Washington and California, because of a dramatic collapse in Pacific sardine stocks. The ban affected about 100 fishing boats with sardine permits, although far fewer were actively fishing at the time. The season normally would end June 30.[82] The ban was expected to last for more than a year, and was still in place as of May 2019.[83]

The manner in which sardines can be packed in a can has led to the popular English language saying “packed like sardines”, which is used metaphorically to describe situations where people or objects are crowded closely together.[84] The British-Irish poet and comic Spike Milligan satirizes this in his poem “Sardine Submarine”, where a sardine’s mother describes the unfamiliar sight of a submarine to its offspring as “a tin full of people”.[85]

Sardines is also the name of a children’s game, where one person hides and each successive person who finds the hidden one packs into the same space until only one is left out, who becomes the next one to hide.[86]

Among the residents of the Mediterranean city of Marseille, the local tendency to exaggerate is linked to a folk tale about a sardine that supposedly blocked the city’s port in the 18th century. It was actually blocked by a ship called the Sartine.

Question 6

Answer 6

The black-collared hawk (Busarellus nigricollis) is a species of bird of prey in the family Accipitridae. It is monotypic within the genus Busarellus.[3] It has a widespread range of presence, from western Mexico to Uruguay. Its natural habitats are subtropical or tropical moist lowland forests, subtropical or tropical swamps, and swamps.[1]

The adult black-collared hawk has a more or less white head, tinged with buff, and with black shaft streaks on the crown. The body, above and below, and the mantle are bright cinnamon-rufous, paler on the chest. There is a black crescent on the upper breast. The back has scattered black shaft stripes; the flight and tail feathers are black with the base of the tail barred with rufous. The eyes are bright reddish brown, the cere and bill black, and the legs bluish white. Immatures are similar, but blotched with black, including on the crown, and the rufous barring on the tail is more extensive. The pale area on the chest is also more clearly marked. The upper surface of the wings is barred, and the eyes are brown.

The nest is usually placed in a large tree, frequently near water, but sometimes in shade trees in coffee plantations or suburban areas. The nest is lined with green leaves. The female lays three to five eggs, dull white, spotted with pale yellow-brown or red-brown and a few darker freckles. There is no further information on its reproduction.

The black-collared hawk lives on a diet mainly composed of fish. It also eats water bugs and occasionally snakes,[4] lizards, frogs,[5] snails, other molluscs, crustaceans, small birds and nestlings,[6] rodents and other small mammals.[7]

In the 1870s, Ridgeway wrote that Busarellus (then known as Ichthyoborus) had the “general form and appearance of Buteogallus aequinoctialis”, but that it “is much more nearly related to the heliatine groups”, in which he included Milvus, Haliastur, and Haliaaetus.[8] During the early-to-mid 20th century, Busarellus was conventionally placed near Buteogallus in taxonomic order.[8]

The black-collared hawk has the basal phalanges of the inner toe fused, which may be an adaptation to prevent the toe from bending back when catching prey. This feature is shared with Ictinia and with the group of true milvine kites and sea eagles (Milvus, Haliastur, Haliaaetus, and Icthyophaga).[8] Research in molecular phylogenetics during the early 21st century indicates that there is a clear milvine–haliaetine clade that is related to a large group of buteonine hawks and their relatives. Within the buteonine group, Ictinia is near-basal, and Busarellus is a member of a clade shared with Geranospiza, Rostrhamus, and Helicolestes.[9]

Question 7

Answer 7

The spectacled owl (Pulsatrix perspicillata) is a large tropical owl native to the neotropics. It is a resident breeder in forests from southern Mexico and Trinidad, through Central America, south to southern Brazil, Paraguay and northwestern Argentina.[1] There are six subspecies.[3] One is occasionally treated as a separate species called the short-browed or brown spectacled owl[4] but the consensus is that it is still merely a race until more detailed analysis can be done.[5]

The spectacled owl is found in Mexico, Central America (Belize, Guatemala, El Salvador, Honduras, Nicaragua, Costa Rica, Panama), Trinidad and Tobago, and South America (Colombia, Venezuela, Suriname, French Guiana, Guyana, Paraguay, Ecuador, Peru, Bolivia, Brazil, Argentina).[1] The spectacled owl is primarily a bird of tropical rainforests, being found mostly in areas where dense, old-growth forest is profuse. However, it may enter secondary habitats, such as forest edges, especially while hunting. On occasion, they have been found in dry forests, treed savanna plains, plantations and semi-open areas with trees. In areas such as Costa Rica, they may inhabit subtropical montane cloud forests of up to 1,500 m (4,900 ft), although are generally associated with lowland forests.[4]

The spectacled owl can range from 41 to 52.3 cm (16.1 to 20.6 in) in length. Mass in males can range from 453 to 1,075 g (1.00 to 2.37 lb), where as females can weigh from 680 to 1,250 g (1.50 to 2.76 lb). 10 males from the nominate subspecies (P. p. perspicillata) were found to average 767 g (1.69 lb) while 8 females averaged 908 g (2.00 lb).[6][7] It is unmistakable in most of its range (except with other Pulsatrix owls) with blackish brown upperparts, head and upper breast, white facial markings and whitish to yellowish-ochre underparts. The eyes are yellow, the only Pulsatrix with this eye color, and the beak is pale. The juvenile is even more distinctive than the adult, being completely white apart from a chocolate brown facial disc. The head is typically darker than the back and mantle but the shade of this area besides the composition of the breast band is the main distinguishing external feature of the subspecies.[4] Compared to the band-bellied owl (P. melanota), it is of similar or slightly larger size, but that species has dark eyes, white eyebrows and a brown chest band broken by buffy-whitish barring the rest of broadly the underparts being whitish with reddish-brown barring. The spectacled owl is generally found at lower elevations than the band-bellied but their ranges overlap or abut from Colombia to northern Bolivia. The tawny-browed owl (P. koeniswaldiana), found from northeastern Argentina to eastern Brazil, is fairly similar in appearance to the spectacled but is marked smaller with ochraceous-tawny from the eyebrows down to the belly and dark chestnut eyes. Each of the three currently recognized species also has a distinct song.[4]

Vocal activity tends to be most prominent on calm, moonlit nights. The primary sound made by the spectacled owl consists of guttural knocking or tapping sounds with a popping effect: PUP-pup-pup-pup-po, POK pok pok bog bog bog bobobo or BOO Boo boo boo boo. Each progressive note becomes weaker and lower in pitch but faster in pace as the call continues. The male is the primary singer to proclaim a territory, often singing from the upper third of a tall tree. However, females also sing, uttering the same song but with a higher pitch. Duets between pairs have been heard on moonlit nights. Females also make a hawk-like scream with an emphasis on the drawn-out second syllable, ker-WHEEER, which has often been compared to a steam-whistle. Young spectacled owls beg with a harsh, high-pitched keew call.[4] In Colombia, an author noted that the song is similar to the tapping pattern of the great spotted woodpecker (Dendrocopos major). In Brazil, spectacled owls are known locally as “knocking owls”.[8]

This species is largely nocturnal, starting activity right around the time of last light at dusk and usually being back on their roosts for the day around first light. It is a solitary, unsocial bird, usually roosting singly each day and only peaceable associating with others of their own species for reproductive purposes.

The spectacled owl is typically the largest and most dominant owl in its range, with the larger great horned owl (Bubo virginianus) rarely venturing into true rainforest habitats. Most hunting starts with the owl perched on a branch and scanning the area, then dropping with a quick pounce when prey is located. It preys principally on a wide array of mammals, eating almost anything that is nocturnally active. Various rodents may be primary but virtually any type of small mammal in its habitat is vulnerable. The primary food by far in Oaxaca, Mexico was the Peters’s climbing rat (Tylomys nudicaudus) followed by mouse opossums (Marmosa ssp.) of unidentified species.[12] Numerous bats, such as greater spear-nosed bats (Phyllostomus hastatus) and broad-eared bats (Nyctinomops laticaudatus), are also rather vulnerable apparently.[4][13][14] Smaller monkeys such as tamarins (Saguinus ssp.) may be vulnerable to predation.[15] Prey species can be heavier than the preying owl, weigh over 1.5 kg (3.3 lb), possibly up to 2 to 4 kg (4.4 to 8.8 lb) in Didelphis opossums, Mephitis skunks and agoutis (Dasyprocta ssp.). Even the three-toed sloth (Bradypus variegatus) has been reported to have been killed, specifically an adult female estimated at 3.5 to 4.5 kg (7.7 to 9.9 lb) in weight or more than four times the weight of the owl itself.[16][17] Invertebrates are eaten regularly as well, second only in importance to mammals, and may be comprised mainly by caterpillars, but also crabs, snails, large insects and spiders.[4] Insects may be gleaned directly from foliage while the large owls actively forage. Frogs are also recorded amongst their prey. Birds are also taken, including mainly medium-sized species in the average weight range of 100 to 500 g (3.5 to 17.6 oz), such as jays, oropendolas (Psarocolius ssp.), motmots (Momota ssp.), and pigeons (Patagioenas ssp.), which are taken off of their nocturnal perches and perhaps smaller types of owl.[4][7][12] Little is known how spectacled owls interact with other owls but a study where playback of a number of owl species were played in Costa Rica, spectacled owls appeared to the least responsive, neither vocally stimulated by the calling of other owl species nor by playback of calls of their own species.[18]

Reproduction
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The young
In Costa Rica, eggs are laid variously in the dry season (November–May), or at the start of the wet season (June–July). This owl typically nests in an unlined tree cavity but may also use the crutch of a large tree. Like all owls, they do not build a nest so just lay their nest on the bare surface of the wood given, usually rotting wood in the case of tree cavities. Spectacled owls lay 1-2 eggs, which are incubated entirely or almost so by the female for about 5 weeks. If two eggs are hatched, often only one of the chicks will survive, the smaller chick usually perishing via starvation or by aggression from the larger nestling. Chicks leave the nest for surrounding branches at about 5–6 weeks but cannot usually fly well at this stage. However, they tend to depend on their parents for several months after leaving the nest and may be cared for and fed for up to a year once fledged, inhibiting the pair’s ability to have young the following year. Spectacled owls may breed while still in immature plumage since it may take up to five years before full adult plumage is obtained.[4]

The spectacled owl occurs over a very large range and is still a resident in much of its range. Due to this, it is classified as Least Concern by the IUCN. However, being a large, slow-maturing bird of prey with a strong sense of territoriality, it as a rule occurs at low densities. In areas where prey populations are hunted by people and habitats are destroyed or compromised, they may decrease. This is the likely source of extinction for an entire race on Trinidad (P. p. trinitatis).[8] Occasionally, when roads are cut into the forest, they are killed by automobile collisions.[19]

Question 8

Answer 8

The rufescent tiger heron (Tigrisoma lineatum) is a species of heron in the family Ardeidae. It is found in wetlands from Central America through much of South America.

The rufescent tiger heron was described by the French polymath Georges-Louis Leclerc, Comte de Buffon in 1780 in his Histoire Naturelle des Oiseaux from a specimen collected in Cayenne, French Guiana.[2] The bird was also illustrated in a hand-coloured plate engraved by François-Nicolas Martinet in the Planches Enluminées D’Histoire Naturelle which was produced under the supervision of Edme-Louis Daubenton to accompany Buffon’s text.[3] Neither the plate caption nor Buffon’s description included a scientific name but in 1783 the Dutch naturalist Pieter Boddaert coined the binomial name Ardea lineata in his catalogue of the Planches Enluminées.[4] The rufescent tiger heron is now placed in the genus Tigrisoma that was erected by the English naturalist William Swainson in 1827.[5][6] The genus name Tigrisoma combines the Ancient Greek tigris, meaning “tiger” and somā, meaning “body”; the specific epithet lineatum is from the Latin lineatus meaning “marked with lines”.[7]

The rufescent tiger heron is a medium-sized heron, measuring 26–30 in (66–76 cm) in length,[nb 1][9] with a mass between 630 and 980 g (22 and 35 oz).[10] The sexes are similarly plumaged.[11] The adult’s head, neck and chest are dark rufous, with a white stripe down the center of the foreneck. The remainder of its upperparts are brownish with fine black vermiculations, its belly and vent are buffy-brown, and its flanks are barred black and white.[12] Its tail is black, narrowly barred with white.[13] Its stout bill is yellowish to dusky, and its legs are dull green.[12] Its irides, loral skin, and orbital ring are bright yellow.[13] Unlike other tiger herons, it has no powder down feathers on its back.[11]

The juvenile bird is rusty-buff overall, coarsely barred with black; the buff and black banding on its wings is especially pronounced. Its throat, central chest, and belly are white. It takes some five years to acquire adult plumage.[12]

Similar species
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The adult rufescent tiger heron is relatively easy to distinguish from fasciated and bare-throated tiger herons, as it is rufous (rather than primarily gray) on the head and neck. Young birds, however, are much more difficult to identify.[9]

The rufescent tiger heron is found in wetlands from Central America through much of South America.[12] It generally occurs below 500 m (1,600 ft), though it has been recorded as high as 1,600 m (5,200 ft) in Colombia.[9]

It is largely crepuscular and generally solitary.[9][13]

Food and feeding
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As might be expected of a species that spends most of its time by the water, much of the rufescent tiger heron’s diet is aquatic-based, including fish, crustaceans, water beetles, and dragonfly larvae. It also takes adult dragonflies and grasshoppers.[11] It typically hunts alone, standing hunched in shallow pools or wet areas of a forest while it waits for prey.[9]

Voice
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The rufescent tiger heron’s main call is a low-pitched paired hoot, often given at night.[12] It also gives a fast series of sharp wok notes, which decrease in volume and speed, and a prolonged hoot, transcribed as ooooooo-ooh which rises markedly at the end.[9]

Although the rufescent tiger heron’s population size and trend has not been quantified, its range is huge, so the International Union for Conservation of Nature lists it as a species of least concern.[1]

Question 9

Answer 9

The agami heron (Agamia agami) is a medium-sized heron. It is a resident breeding bird from Central America south to Peru and Brazil. It is sometimes known as the chestnut-bellied heron, and is the only member of the genus Agamia. In Brazil it is sometimes called Soco beija-flor, meaning ‘hummingbird heron’, thanks to its unique coloration pattern.[2]

The agami heron is listed as vulnerable by the IUCN, due to predictions of future habitat destruction within its range.[1]

The agami heron was formally described in 1789 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus’s Systema Naturae. He placed it with the herons and cranes in the genus Ardea and coined the binomial name Ardea agami.[3] Gmelin based his description on the “Agami heron” from Cayenne that had been described in 1785 by the English ornithologist John Latham in his book A General Synopsis of Birds.[4] Latham had in turn based his description on a specimen owned by the army officer Thamas Davies and the description and illustration of “Le Héron Agami” by the French polymath Comte de Buffon in his Histoire Naturelle des Oiseaux.[5][6] The agami heron is now the only species placed in the genus Agamia that was introduced in 1853 by the German naturalist Ludwig Reichenbach.[7][8] The name agami is the word for a forest bird that was used by the indigenous people of French Guiana.[9] The species is monotypic: no subspecies are recognised.[8]

This uncommon species is 66–76 centimetres (26–30 inches) in length. It is short-legged for a heron, and has a thin bill which is considerably longer than the head. The neck and underparts are chestnut, with a white line down the centre of the foreneck, and the wings are shiny green. Wispy pale blue feathers decorate the crown, sides of the foreneck, and lower back. The legs, bill, and bare facial patch are dull yellow. During the breeding season the facial patch can change color to reddish. The sexes are similar, but juveniles are largely brown above with a white foreneck, and streaked brown-and-white underparts. The normal clutch size is two blue eggs.

The agami heron is a Neotropical species occurring in Central and South America. The distribution area of the species extends from south-east Mexico through central and Caribbean Central America through the Amazon basin in South America, covering the following countries: Mexico, Guatemala, Belize, El Salvador, Honduras, Nicaragua, Costa Rica, Panama, Colombia, Ecuador, French Guiana, Suriname, Guyana, Venezuela, Peru, Bolivia and Brazil.

This species is rare in open areas. The agami heron’s habitat encompasses swamp forests, mangroves, forest streams and freshwater wetlands. They mostly occur at elevations between sea level and 300 metres (1,000 feet), although records exist from as elevations as high as 2,600 metres (8,500 feet) in the Andes. They nest in both single species and mixed species colonies on platforms of sticks in bushes and trees over water. Very few colonies are known to date but some are quite large, up to hundreds or even over a thousand nests.[10] The following locations of colonies are known within the distribution area of the species:on a tiny island at the centre of a lagoon in the middle of the Pacuare Nature Reserve, Costa Rica, in the Tapiche Reserve, Peru, the Marais de Kaw-Roura National Reserve and Amazonian National Park, French Guiana, and other colonies outside of protected areas in Colombia, Mexico and Belize.[11]

Despite its stunning plumage, this reclusive species’ preference for shade and overhanging vegetation means that it is rarely seen. This is a quiet bird, but pairs and family groups may make various snoring or rattling sounds. Rattling sounds and slow walking away are a typical response to disturbance.[12]

Agami herons stalk their prey (fish, frogs, small reptiles, and snails) in shallow shaded water in forested areas. They often standi still on perches or directly in the water, or moving very slowly.[12] They rarely wade in open water. The majority of their prey consists of characins (Triportheus angulatus and Astyanax angulatus) which are surface-swimming fishes. Less commonly, they have also been known to consume cichlids (Aequidens).[13]

Several courtship behaviors have been described and are used by both sexes.[12] Lores can change color to an intense red, and both sexes show a short-lived silver crest.

This species is very discreet and scientifically little known, which is a challenge for conservationists. Its remote habitat and secretive behavior may explain its apparent rarity. However, it is considered as Vulnerable by the IUCN Red List due to future habitat loss in the Amazon.[1] Conservation efforts should concentrate on protection of important colony sites, developing a better understanding of the range, habitat needs and biology of the species.[11]