Mammals Flashcards
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
