Mammals Flashcards
Groupings
Monotremata - prototheria
Marsupialia - Metatheria
Placentalia - Eutheria
Mammals identification
Backbone/fur/nurse infants with milk - unique jaw articulation
Mammae - mammary glands - milk production - mammilae - nipple/teat - milk delivery
2X nipples to litter size
Articulate + quadrate bones - no longer visible in jaws (became incorporated into middle ear
Teeth replaced once or never - - enamel
Secondary palet
Monotremata
Retain reptilian features
Lay + brood eggs
Single hole - cloaca
Infants lap milk from nippless mammary glands from tufts of hair
Lack teeth - can be venemous
4 Echidna + 1 DB platypus
Echidnas
Spines are modified hairs
Modified spines on back of tongue + roof of mouth - crush insects
Ant + termite diet
Eggs hatch after 10 days - 2 week gestation
Young move to pouch - feed on milk for 6 months
Platypus
Webbed feet
Hunt for benthic invertebrates by electrolocation
2 eggs per burrow - 10 day incubation - no pouch - 3-4 month lactation
Males have spurs on rear ankles connected to venom glands in thighs
Marsupials
Prolonged lactation
Many outcompeted by eutherians
S + N America + Oz
Convergent evo with eutherians
Sugar glider (M) - Northern flying squirrel (E)
Tasmanian devil - Hyena
Kangaroo - patagonian mara
Southern marsupial mole - European mole
Marsupial reproduction
Gestation is short
Newborn poorly developed - well developed forelimbs
Crawl to nipples in pouch
Females cna become pregnant during lactation + embryo can be arrested at blastocyst stage
Kangaroos can have joey at heel - second offspring on pouch nipple and an arrested blastocyst in uterus
4 super orders of placental mammals
Afrotheria - Africa
Xenarthera - SA
Laurasiatheria
Euchontoyliers
Afrotheria
6 orders
Tenracs + golden moles - adaptive radiation - resemble shrews, hedgehogs + otters
Sengis - Elephant shrew
Aadvark
Elephants
Hyraxes
Dugons + manatees
Xenarhtera
Pilosa - anteaters + sloths
Cingulata - armadillos
Teeth reduced or lost
Have large claws on toes
Low energy content diet - lower metabolic rate than expected 33-60%
Anteaters - long sticky tongue
Sloths - slow aboreal lifestyle - cellulose digesting bacteria in large stomach - pass waste 1 a week
Armadillos - tough carapace - strong bony, plates - 3-13 bands - 3 banded can roll into ball
Eulipotyphla
Shrews/ solenodons/ hedgehogs + moonrats/moles +desmans
Nocturnal - poor vision - other senses well developed
Small smooth brain
Many teeth
Intra-abdominal testes - no scrotum
Cloaca
High SA:V ration - high heat loss - shrews eat own mass in inverts a day
Shrews
Some can emit ultrasonic clicks - may be crude form of echo
Mainly insectivorous - some have venemous bites
Solenodons
Crude echo
Toxic saliva to immobilise prey
Cartilaginous snout - articulates with skull via ball + socket joint
Found on 2 Caribbean islands
Hedgehogs + moonrats
Moonrats have no spines
Spines for defence - hollow to reduce weight
Spines make grooming impossible - many parasites
Heterothermy - internal temp follows external
Moles + desmans
Poor vision - richly endowed tactile organs - eimers organ on muzzles
Vibrissea on muzzle + tail (legs of desmans) - sensory whiskers
Lagomorphs
Rabbits/hares/pikas
Peg teeth - 2nd pair of incisors behind upper pair
Coprophagy - reingestion of faecal matter
Prolific breeders - induced ovulation - response to mating
Superfetation - conceiving 2nd litter before birth of last young
Rodentia
Squirrel like/mouse like/cavy like
Squirrel + mouse like - sciurognathi
Cavy like - hystricognathi
Squirrel - beavers/squirrels/springhare
Simple teeth - lackong large cusps - sharp enamel
bill balls - lots of sperm
mulitiparental litter
Mouse like - Rats/mice/voles/lemmings/hamsters/kangaroo rats
1/4 of mammal species
Main seed diet
Adapted for early + prolific reproduction
Cavy-like - cavies/capybaras/agoutis/chinchillas/porcupines/mole rats
Mole rat reproduction
Subterranean
Social structure resembles that seen in some insects
Single pair breed in each colony
Remaining animals belong to castes
1-3 males but 1 female
Small animals carry food + nest material
Larger - breeding + defence
Young cared for by all females - suckle on breeding female
Non breeders - can start new colonies (not sterile)
Ungulates
Hoofed mammals
Perissodactyla (odd toe)
Artiodactyla (even toe)
Perissodactyla
(Horses/zebras/asses) - Tapirs - rhinos
1/3 toes
Rely on vocal communication
Tapir - many preds
Artiodactyla
(pigs/peccaries/hippos) - (camels/llamas) - Ruminants
Use scent for comms
Ruminants
Chevrotains - musk deer - deer - giraffe + okapi - pronghorn - bovids - antelopes - gazelles - cattle - sheep - goats
Deer + bovids
True deer (cervidae) - antlers - made of bone - regrown annually - serve in intrasexual selection
Reindeers - both sexes have antlers
Bovidae have horns
Carnivora
Skulls adapted for killing + crushing
Large canines - cusps on last upper pre molar + first lower molar form carnassial teeth for slicing meat
Hyaenas - kleptoparasites - theft - high conc HCL - extract nutrients from bone - penis like clitoris in females
Ursidae - bears - panda - veg
Felidae - most carnivourous
Lion social organisation:
core of pride - 4-12 related females
Sub adult males tolerated
Breeding male does not grow up in pride it holds
Females - allosuckling of relatives offspring
Incoming males may kill young to gain paternity
Pinnipeds
Seals, sealions, walrus
Eared seals - fur seals + sea lions
True seals
Feed offshore give birth on ladnd
Walrus
Both sexes have tusks
Skull specialisation for feeding on benthic prey - clams
Eared seals
Fur seals + sealions
Large fore flippers for propulsion (sustained swimming)
Hind limbs play no part in sustained swimming
More agile on land than true
True seals
Hind limbs for swimming
Main muscle mass at rear
Not agile on land
Grey + common seals
Click vocalisations underwater (may be used in echo)
Delayed implantation (store the reproduction process)
Limited mother pup contact - short lactation period with high E milk
Elephant seal social organisation
Highly polygynous
Males 3x mass of female
Large proboscis
No paternal care
Undergo bloody fights for dominant position
Alpha can inseminate up to 100 females a season
Polygyny consequence of high no. of ejaculate and limited number of young a single female can output
Male pups attempt to steal milk from other females (not seen in female)
Sirenia
Manatees + dewgong
Elephants closest relative
Only MMs that primarily feed on plants
Non compartmentalised stomach - long intestine (45m in manatees)
Expend v little energy
Move slowly
Constant replacement of teeth - allows for eating of plants with abrasive silica
Store lots of fat - manatee can fast for up to 6 months
Cetatians
Whales + dolphins
related to hippo
Baleen whales - horny plate made from keratin for filtering plankton - separate nostrils in blowhole - very large tongue - used for sucking water in mouth via pressure differences
Blue whale - 27m - 150 tonnes - streamlined - no hind limbs - no external ears or genitalia - horizontal fins - boneless tail fluke
Toothed whales - eat fish + squid - jaws extend as beak like snout - rises as ‘melon’ in rounded curve - single nostril
Echolocation in toothed whales
less visibility in water - sound travels further
Brief clicks - sound produced by monkey lips in nasal passages
Melon focuses sound at forehead
returning sounds channeled through oil filled sinuses in lower jaw
Inner ear isolated in bubbly foam
Sperm whales can produce intense ultra sound - stun?
Several fish can detect ultrasound
Long distance communication in cetations
lower frequencies can travel further
Sound can travel up to 5600km in the right conditions
Humpback whale songs can change annually
Chioptera
Bats
Megachiroptera - fruit bats - bigger eyes - smaller ears
Microchiroptera - others - smaller eyes - bigger ears
Megachiroptera
Most orientate visually - no echolocation
Some click tongue on sides of mouth as primitive form of echo
Large size
Microchiroptera
Most are small
All use laryngeal echolocation for orientation (some for prey detection)
Bat wings
Modified pentadactyl limb
Fast - long narrow - little drag - high wing loading and AR - low manoeuvrability - open areas
Slow flight - low AR + WL - high manoeuvrability - forest species
Feeding in bats
Active + passive gleaning
Frugivory - Crushing + grinding molars - evolved from insectivores - insects around fruit
Nectavory - Evolved from insects visiting flowers - carbs + protein - some flowers evolved to attract bats
Piscivory - detect ripples on water surface by echo - big feet
Carnivory - some large species eat small mammals, geckos, bats , frogs
Sanguivory - Vampire bats - evolved from feeding on flies around wounds - laps blood - anticoagulant
Reciprical altruism
Vampire bats
females associate in roosts
others regurgitate for unsuccessful females - favour returned
can starve in 3 days
Scandentia
Tree shrews
Semi terrestrial - like squirrels
omnivores
Long linked to primates
born in naked and helpless condition (limited parental care
Dermoptera
Flying lemurs - colugos
Patagium allows gliding
Stereoscopic vision for depth perception
Nocturnal
Sirrhini
Lorises - bush babies - aye aye - lemur
Lemurs - Madagascar - monogamous - molars still triangular - binocular field for arboreal lifestyle (narrower)
Aye Aye - special dentition - spindly middle finger - Eats fruit + insect larvae - continuously growing incisors
Haplorrhini
Tarsiiformes
comms with ultrasonic calls
Only animal prey
Biggest eyes to body size ration
Simiiformes
Monkeys - apes - humans
Platyrrhini
Catarrhini
Platyrrhini
New world monkeys
Marmosets - tamarins
Wide spread nostrils - flat nose
retain all 3 pre molar teeth
Arboreal - prehensile tail
Catarrhini
Old world monkeys - apes + humans
Downward pointing nostrils
2 pre molars on each side of jaw
Cercopithecidae
Old world
macaques + baboons
blue faces + blue balls
Hylobatidae
Gibbons
arboreal
monogamous
Complex vocals - laryngeal sacs
Vervet monkey alarm calls
Different call for different predator
Leopard - run into trees
Eagle - look up
snake - look down
Campbells monkey
2 basic calls - booms + hacks
hacks for predators
Can combine with other sounds to convey extra info
Can transform highly specific eagle alarm –> general arboreal disturbance
Can transform leopard alarm –> general alert call
Primate social groups
defence against predators makes sharing food worth
Gibbons - monogamous pairs - up to 4 immature offspring
Bushbabies - range of several females + offspring overlap - males occupy larger areas that overlap
Gorilla - groups compromise of single male - harem of females + young
Chimpanzees - groups of unrelated females have individual home ranges - females monopolised by groups of related breeding males
Gelada baboon - groups of harems in shared territory - males unable to hold harem o excluded
Yellow baboon - multi mate troops - several breeding males - many breeding females - strong dominance heirachies
Monogomy only tends to occur when food is concentrated in area small enough to defend
if female group is too large to be defended by 1 male - more join group
