Chapter 12 Flashcards
What are marine mammals?
Mammals that live and feed in the marine (aquatic) environment
What are Mammals
Mammary glands – nurse young with milk
Hair
Diaphragm
Vertebrate Comparisons
Fishes – Poikilotherms, 2 chambers, Scales
Reptiles – Poikilotherms, 3 chambers, Scales
Birds – Homeotherms, 4 chambers, Feathers
Mammals – Homeotherms, 4 chambers, Hair
Homeothermic
refers to the ability of an animal to maintain a constant body temperature
Mammary glands
are the milk producing glands of mammals
Placental mammals
are mammals that retain their young inside their body until they are ready to be born
Placenta
is an organ found in pregnant placental mammals that sustains the young until they are born
Order Carnivora
Carnivora
Polar bears, sea otters, seals, sea lions, walruses
Order Sirenia
Sirenia
Manatees, dugongs
Order Cetacea
Cetacea
Baleen whales, toothed whales (e.g. sperm,
dolphin, beluga, porpoise)
5 Families of Marine Mammals
Carnivora
Mustelidae – Sea otter
Ursidae – Polar bear
Phocidae – Seals (true seal)
Otariidae – Sea lions (eared seals)
Odobenidae - Walrus
Family Mustelidae members, distribution and diet
Carnivora
Sea otters are found along the coasts of the North Pacific; live and feed in kelp forests
Eat urchins and molluscs (25% body wt/day)
Family Mustelidae features
Carnivora
Webbed 5-digit fore and hind limbs
Densest animal fur (350,000 per in2)
Family Mustelidae life style and behaviors
Carnivora
Spend virtually all of their lives in the water
Are constantly grooming their fur to maintain the waterproof insulating quality of the underfur
Family Mustelidae importance
Carnivora
Keystone species in kelp forests; when otters decline, kelp declines
Family Ursidae members, diet, and distribution
Carnivora
Polar Bears are the largest bear species, land carnivore in North America and the top predator in the arctic marine ecosystem
Primarily feed on ringed seals; eat their blubber
Family Ursidae features
Carnivora
Partially webbed forepaws; strong swimmers
Family Ursidae hunting
Carnivora
Hunt seals primarily along pack-ice or fast-ice
Finds seal burrows by scent; collapses them
Pinniped
Carnivora
is a marine mammal with flipper-like appendages; “feather-footed”
34-36 species – (25% of marine mammals)
Family Phocidae members
Carnivora
true seals
Family Otariidae members
Carnivora
Eared/fur seals
Family Odobenidae members
Carnivora
Walruses
Phocids
Carnivora
are seals that lack external ears and are known are true seals
- Hawaiian monk seal
Otariids
Carnivora
are seals that have external ear flaps and are known as sea lions or fur seals
- California sea lion
Pinniped Swimming
Carnivora
Pinnipeds are accomplished swimmers and divers; can typically swim as fast as cetaceans (whales & dolphins) but only for short durations
Pinniped Diving
Carnivora
Pinnipeds are some of the longest and deepest diving mammal; Phocids dive deeper and longer than Otariids
Diving Adaptations
Carnivora
Cease breathing during diving events
which causes conflicting conditions
1. O2 stores ↓ with ↑ activity (O2 demand)
2. CO2 & lactate ↑ in blood & muscle
Once O2 is used up, muscle activity is maintained anaerobically which results in
↑ accumulation of lactate
Hemoglobin
O2 binding molecule of red blood cells; can deliver O2 where needed
Myoglobin
O2 binding molecule of muscle cells; delivers O2 directly to muscles
Hematocrit
packed red blood cell volume; hemoglobin volume – higher in mammals with increased diving capacity
Dive Response
During dive, available O2 ↓ (hypoxia) and CO2 ↑ (hypercapnia)
Together create asphyxia
Anaerobic diving
a dive that does not use O2; lactic acid & H+ ions accumulate
Bradycardia
decline in heart rate
Ischemia
preferential distribution of blood to O2 sensitive organs; temperature & metabolic rate
Decreased heart rate varies from
modest (sirenians), moderate (cetaceans) extreme (phocids)
Phocids (besides elephant seals) reproduction
Carnivora
typically give birth with individual females residing alone
Otariids reproduction
Carnivora
typically aggregate in large numbers at an established breeding beach or rookery to give birth
Polygynous
refers to the situation in which a males mates with more than one female
Seasonal delayed implantation
is a process in which the implantation of an embryo in the mother’s uterus is delayed in order to allow for birth to occur at the most opportune time
Gestation period
the period of pregnancy
Process where that fertilized egg undergoes several cell divisions forming a Blastocyst
Blastocyst
is an early developmental stage in mammals characterized by a hollow mass of cells
The blastocyst can remain in the female’s uterus for weeks to months before continuing development
Lactation period
is the period of time that a female mammal is producing milk and nursing her young
Most energetically expensive aspect of reproduction
Best interest to pass as much energy as possibly even at expense of future offspring
Fasting Lactation Strategy
Example: Northern elephant seal
Carnivora
Duration of fasting: All of lactation
Duration of lactation: Short (4-weeks)
Fat content of milk: High (55%)
Pups forage during lactation: No
Foraging Cycle Lactation Strategy
Example: Antarctic fur seal
Carnivora
Duration of fasting: Variable (few days)
Duration of lactation: Intermediate (4-months)
Fat content of milk: Intermediate (40%)
Pups forage during lactation: No
Aquatic Nursing Lactation Strategy
Example: Walrus
Carnivora
Duration of fasting: Short (hours-days)
Duration of lactation: Long (2-3 years)
Fat content of milk: Low (2-3%)
Pups forage during lactation: Yes
Family Otariidae subfamilies
Carnivora
Subfamily Arctocephalinae – Fur seals
- Dense pelage
Subfamily Otariinae – Sea Lions
- Pelage sparse
Family Phocidae
Subfamily Monachinae
members
Carnivora
Hydrurga leptonyx
- leopard seal
Antarctic seals
Neomonachus schauinslandi
- Hawaiian monk seal
Monk seals
Mirounga angustirostris
- northern elephant seal
Elephant seals
Family Phocidae
Subfamily Phocinae
members
Carnivora
Phoca vitulina
- harbor (common) seal
Histriophoca fasciata
- ribbon seal
Pagophilus groenlandicus
- harp seal
Cystophora cristata
-hooded seal
Family Odobenidae
members
Carnivora
1 species – Walrus - Odobenus rosmarus
- 2-3 subspecies
Odobenus r. rosmarus – N. Atlantic
Odobenus r. divergens – N. Pacific
(Odobenus r. laptevi – Laptev Sea)
Family Odobenidae
relations and tusk use and origin
Carnivora
Debate as to whether closely related to Otariids or Phocids
Use tusks (modified canine teeth) for:
Competition (walruses)
Defense (predators)
Hauling out (pick-axe)
Resting (anchor)
Order Sirenia families, adaptations, and habitats
Sirenia
Trichechidae – manatee (3 species)
- Paddle-shaped tail, freshwater/estuarine
Dugongidae – dugong (1 species)
- Fluke-shaped tail
Marine; has tusks
Sirenians
Sirenia
mammals belonging to the Order Sirenia
Tail flukes
Sirenia
are the lobes of a sirenian or cetacean tail
Family Trichechidae
members
Sirenia
Trichechus senegalensis
- West African manatee
Trichechus inunguis
- Amazonian manatee
Trichechus manatus
- West Indian manatee
2 subspecies:
Trichechus m. latirostris
- Florida manatee
Trichechus m. manatus
Antillean manatee
Family Dugongidae
members
Sirenia
Dugong dugon
- Dugong
Hydrodamalis gigas
- Steller’s sea cow (Extinct; known for 27yrs)
Cetaceans
are marine mammals belonging to the order Cetacea; includes whales, dolphins, and porpoises
- most extensively adapted to the marine environment
Blowhole
is an opening of the top of a cetacean’s head that contains the nostrils
Blubber
is a thick uniform layer of fat under the skin of some marine mammals (pinnipeds, sirenians, cetaceans)
Alveoli
are the tiny spaces, or gas sacs, within the lungs where gas exchange occurs
The Bends
is a condition that occurs when nitrogen gas dissolved in the blood comes out of solution and forms gas bubbles as the pressure decreases during an ascent from deep water, causing disruptions in circulation
Lactic acid
is a waste product produced when cells metabolize anaerobically
Spy hopping
is a cetacean behavior in which the animal raises its head out of the water
Breaching
is a cetacean behavior in which the animal completely or almost completely leaves the water
Tail slapping (tail lobbing):
is a cetacean behavior in which the animal lifts its tail out of the water and slaps it down hard on the surface
Peduncle
is the part of the whale’s body closest to the tail fluke
Fluke up
is a cetacean behavior in which the animal brings its fluke above the water so that the ventral surface is visible
Fluke down
is a cetacean behavior in which the animal brings its fluke above the water so that the dorsal surface is visible
Flipper flapping (Pec slapping):
is a cetacean behavior in which the animal rolls over onto its back and flaps its flippers in the air
Pectoral stroking
is a cetacean behavior in which one animal strokes the body of another with its pectoral fin
Suborder Mysticeti
baleen whales (12-14 species)
Suborder Odontoceti
toothed whales, dolphins, porpoises (≈ 75 species)
Baleen whales (Suborder _______) are characterized by
Mysticeti
Lack of teeth
Presence of baleen plates
Two external blowholes
Balaenidae
Right whales
Balaenopteridae
Rorquals
Eschrictiidae
Gray whale
Neobalaenidae
Pygmy right whale
Baleen
is a structure made of protein that is used by baleen whales to filter food from the water
Keratin
is a tough protein that makes up baleen
Northern Right
Eubalaena glacialis
Southern Right
Eubalaena australis
Bowhead
Balaena mysticetus
Gray whale
Eschrichtius robustus
Blue whale
Balaenoptera musculus
Sei whale
Balaenoptera borealis
Eden’s whale
Balaenoptera edeni
Antarctic Minke
Balaenoptera bonaerensis
fin
Balaenoptera physalus
Bryde’s
Balaenoptera brydei
Minke
Balaenoptera acutorostrata
Omura’s
Balaenoptera omurai
Humpback
megaptera novaeangliae
Toothed Whales
(Suborder)
(Suborder Odontoceti)
characterized by:
Teeth
Echolocation
One external
blowhole
10 Families
Family Ziphiidae
Beaked Whales
Relatively poorly known; diverse group
Characterized by a snout drawn into a beak
Inhabit deep ocean basins
Most information
comes from
strandings &
whaling
Family Physeteridae
Physeter macrocephalus – Sperm whale
Sperm whale
Physeter macrocephalus
Spermaceti
is a waxy substance found within the rostrum of sperm whales (dolphin melon)
Ambergris
is a section of the sperm whale’s digestive tract; base for perfumes
Family Kogiidae
Kogia breviceps – Pygmy sperm whale
Kogia sima – Dwarf sperm whale
Pygmy sperm whale
Kogia breviceps
Dwarf sperm whale
Kogia sima
Family Platanistidae
Platanista gangetica - Ganges & Indus river
Asian River dolphins - blind
Long, narrow beak, numerous pointed teeth, broad paddle-like flippers
Family Pontoporiidae
Rivers of South America (Atlantic)
Pontoporia blainvillei - Franciscana
Family Iniidae
Inia geoffrensis - Bouto
Found in Amazon river
Exclusively freshwater; reduced eyes
Elongate rostrum
Conical front teeth;
Molariform back teeth
Family Lipotidae
Lipotes vexillifer – Baiji, Chinese River
Found in Yangtze river
Long narrow upturned beak, low triangular dorsal fin
broad flippers
very small eyes
Family Delphinidae
Oceanic dolphins
Dephinids
is the collective term for members of the cetacean family Delphinidae, specifically dolphins
Most diverse cetacean family – 17 genera
Includes dolphins and “whales”
- bottlenose dolphin, spinner dolphin, pilot whale, killer whale (Orca:) is another name for a killer whale (based on genus)
Family Phocoenidae
Porpoises
Family Monodontidae
Delphinapterus leucas - Beluga
onodon monoceros - Narwhal
Echolocation
is the process that allows toothed whales to use sound to distinguish objects from distance
Orientation clicks
are low frequency clicks used in echolocation that give an animal a general idea of its surroundings
Discrimination clicks
are high frequency clicks used in echolocation that give an animal a precise picture of a particular object
Signature whistle
is a unique sound produced by a dolphin to identify an individual
Melon
is an oval mass of fatty, waxy material in a dolphin’s head that functions in directing and focusing the sounds used in echolocation
Ganges & Indus river dolphin
Platanista gangetica
Franciscana
dolphin
Pontoporia blainvillei
Bouto river
Inia geoffrensis
Baiji, Chinese River dolphin
Lipotes vexillifer
Finless Porpoise
Neophocoena Phocaenoides
Spectacled Porpoise
Phocoena Dioptrica
Burmeister’s Porpoise
Phocoena Spinipinnis
Vaquita porpoise
Phocoena Sinus
Harbor Porpoise
Phocoena Phocoena
Dall’s Porpoise
Phocoenoides Dalli
Narwhal
Monodon monoceros
Beluga
Delphinapterus leucas