Aquatic Mammals Flashcards
Which 3 orders contain aquatic mammals?
Cetacean, Carnivora, Sirenia
Which Canivore families have aquatic mammals?
Pinnipedia, Ursiade, Musteliade
What are the 2 groups of cetacea?
Mysticetin, Odontoceti
What feeding adaptation do mysticetin’s have?
Baleen - filter feeding
Which 4 families are within mysticetin?
Balaenidae, Neobalaenidae, Balaenopteridae, Eschrichtiidae
What is the odontoceti skull like?
Asymmetrical
Which families are in odontoceti?
Delphinidae, Monodontidae, Phocoenidae, Physeteridae, Plantanistidae, Iniidae, Ziphiidae
Which families are in pinnipedia?
Otariidae, Phocidae, Odobenidae
Which species are in otariidae?
Sea lions and fur seals
What are the features of otariidae?
External ears, better on land, hind flipper for land locomotion, enlarged forelflipper
What are the features of phocidae?
No external ears, more marine adapted, smaller flippers
Which animals are in phocidae?
Seals, elephant seals.
Which animals are in odobenidae?
Walrus
What is a dugong tail like?
Tail fluke - notched
Which animals are in Trichechidae?
Manatees
What is a manatee tail like?
Spatulate
What are the features of cetacea reproduction?
Mating at sea, testes abdominal, penis retractable
What are the features of pinnipidia reproduction?
Harem
What is gestation of aquatic mammals like?
Extended but not relative to size
What is a blue whales gestation like?
Rapid development, extended parental care
Where does birth in cetacea take place?
At sea
Where does birth in pinnipeds take place?
On land
Where does lactation in cetacea occur?
Teats in slits near urogential opening
What is aquatic mammal milk like?
Highly concentrated
How are aquatic mammals insulated?
Subcutaneous fat layer, fur
How does the countercurrent exchange work?
Conserves heat in core, flippers insulated.
Why are sirenia less adapted?
Less body fat, not good at retaining heat. Live in warmer waters
How do marine mammals cope with the hyperosmotic environment?
Metabolic water, concentrated kidneys
How much more myoglobin do marine mammals have?
2-9 x more
What happens to breathing during deep diving?
Extended apnoea, lack of breathing.
How do baleen whales feed?
Keratinous plates
How does lung feeding occur?
Rorquals, throat furrows
How does the mammal withstand the force of water during lunge feeding?
Mandible fraced by frontomandibular
What are bubble clouds?
Groups of humpback whales encircle fish, lung feed
How does sucking and dredging occur?
Plough head through mud, coop and suck up sediment
What is carnivore dentition like?
Sharp canines, simple cheek teeth
How are walrus’ adapted to feeding?
Bentic invertebrates, suck out, discard shells
How are walrus flippers adapted?
Right handed lateralised limb used to root through sediment
How are sea otters keystone species?
Otters harvest the increased urchins to prevent loss of kelp beds
How do sperm whales locate?
Echolocation
How do sirenia feed?
Slow moving grazers, herbivorous
What is the function of fusiform body?
Reduce drag and turbulence
How are lungs adapted for deep sea diving?
Small and elastic
What adaptations do deep sea diving mammals in their respiratory tract?
Rigid cartilaginous airways, flexible ribs, elastic bronchioles
How do sirenia control buoyancy?
Dense, heavy bones. Fermentation gas
How is echolocation produced?
Clicks with air forced through valves in nasal sac
How is echolocation focused?
Through melon lens
Whys vocalisation more important?
High conductance of sound in water
How do mysitcetes create sound?
Larynx, vocal folds.
What is rete mirabile?
Network of blood capillaries between swimming muscles which act as heat exchanger
