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Flashcards in Mammals Deck (10)
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Characteristics of family phocidae (seals)

-Evolved 25 MYA from bear & and weasel like animals.
-propel themselves w/ hind flippers
-internal testes + no external ears
-short lactation/weening periods
-high fat content in milk
Deep divers, eat primarily squid


Characteristics of family Otariidae (sea lions)

-evolved 18 MYA from dog like animals
-long fore flippers; uses to walk on land and swim underwater
-external ears and testes
-eat primarily fish
-spend longer time with young


Characteristics of family Odoberinidae (walruses)

-evolved 22 MYA
-internal ears and testes
-large fore flippers
-bottom feeders; use tusks to rake sediment for food


Characteristics of family Mustelidae (sea otters)

-evolved 15 MYA
-Use tools, store in pockets
-food choices passed down from mother
-eats mostly invertebrates
-high parental investment
-thick fur instead of blubber


Characteristics of family Ursidae (polar bears)

-closely related to grizzly
-live in arctic
-hunt seals in ice leads
-black skin & hollow white fur
-twins; high parental investment (2.5 yrs)
-high sexual dimorphism


Characteristics of Manatees (order Sirenia)

-evolved 56 MYA; elephants
-live over 60 yrs, sexually mature at 10-18
-high parental investment
-eats seagrass and mangroves,60+ species
Red listed; threats- hunting, boat strikes, habitat destruction, slow-moving, k-selected


Families in order Pinnipedia

Phocidae (seals)
Otariidae (sea lions)
Odobenidae (walruses)


Characteristics of Dugongs (order Sirenia)

-evolved 56 MYA; elephants
-live over 70 yrs, sexually mature 10-18
-eat seagrass
-red listed


Diving Physiology

Able to:
-decrease heart rate
-shunt blood away from extremities
-use myoglobin to carry O2
-high blood volume
-flexible, cartilaginous ribs to withstand pressure


Sexual dimorphism prevalence

Low in ice breeders
High in beach breeders