Transcript Mammals - part 1

Mammals Rule!
Mammal Notes
Marine Mammals:
- 65 million years ago dinosaurs disappeared and
mammals thrived
early mammals
Class - mammalia
• Endothermic
• Hair or fur. Whales have stray hair on chin.
• Viviparous- embryo receives nutrients and O2 from
placenta
• Mammary glands for milk production - nurse young
• Produce few young and care for them (prudent)
• Large brain and more complex behavior
Order - pinnipeds (seals, sea lion)
• Predators- feeding on
fish and squid
• Streamline bodies to
swim
• Live in cold H2O
• Thick layer of fatblubber for insulation,
for energy reserve and
buoyancy
• Bristly hair and large size
conserves body heat
• pinnipeds- pinni means wing or fin and pedis
means foot
• Seals- rear flipper
cannot move forward
on land. Pull forward
with front flippers, no
ears, hunted for their
skin, meat, and blubber
• Sea lion- eared seals,
move rear flippers
forward, can walk on
front flippers
sea lion and seals
• Walrus- The largest
pinniped, the only one
with tusks.
• Whiskers- mystacial
vibrissae- are very
sensitive, acting as
feelers, used in foraging.
• Walruses change color,
pink when warm, and
cinnamon when cold.
• Walrus migrate with the ice
floe
• Growth rings on cross
section of teeth
• Tusks can reach 1 m in
length, which are modified
canine teeth.
• Tusks used in male
dominance, making holes
in ice, haul out on ice, and
forage for food.
• Air sac under throat, are
used as floatation device
while sleeping.
• Feed on invertebrates, able
to open clams with powerful
suction created in mouth.
• Walrus only predators are
Orca, Polar Bears and
Humans.
• Scrimshaw- art work
on walrus tusks
Order - Carnivora
Sea otter• Smallest marine
mammal
• No blubber
• Insulation with dense
fur-attracted fur hunters
• Weight between 45 and
65 lbs.
• Eat 7-9 Kg. 15-20 lbs., of
food per day
• Use rock to crush shells