Marine Mammals

Order Sirenia: Manatees and Dugongs

• 1 species dugong• 3 species manatees

Florida Manatee

• Endangered • Herbivore• Migrate in Winter• Inhabit tropical waters

Order Pinnipedia: Sea Lions, Seals and the Walrus

Family Otariidae: Sea Lions

• External ears• Long neck• Performs in shows• Pull hind flipper

under body• Claws ¾ to end of

flipper

Family Phocidae: Seals

• No external ears• Short neck• Back flippers to

swim• Can’t rotate hind

flippers• Claws at end of

flippers

Family Odobenidae: Walrus

• Use vibrissae (whiskers) to feed.

Order Carnivora: Sea Otter

Two North American Species

1. The Alaskan

2. The Californian

Prized for pelt

• Over 1 million hairs/in2

• Need thick fur because they have NO blubber

• Oil on hair to repel water

Oil Spills

• Oil covers fur and otters die of exposure• When otters attempt to clean their fur, they

ingest the oil and die.

Diet

• Eat invertebrates (urchins and abalone).• Use tools.

Order Carnivora: Polar Bears

• Well-developed claws, strong facial musculature, specialized teeth.

Family Ursidae

• Partially aquatic bears.• Inhabit arctic sea ice, water islands &

coastlines.

Adaptations to the Arctic

• Small ears which help conserve body heat.

• 12’’ paws – act like snowshoes• Non-retractable claw (to grip ice)• Thick fur• Fur is oily and water repellent• Skin is black which enables the bear

to absorb sunlight energy to warm its body.

• Have 4 inches of blubber

• Need 4.4 lbs of fat a day to survive. • Polar bears can smell a seal more than 20

miles away.• Feed mainly seals, but will scavenge other

mammals

• No natural predators as adults• Threatened species protected under MMPA (Marine

Mammal Protection Act)• No hunting in U.S., but are hunted in Canada.

Whales

Order: Cetacea

Suborders:

1. Mysticeti = Baleen whales

2. Odontoceti =Toothed whales

Whale Anatomy

• Female whales have a genital slit and 2 mammary slits.

• Males have 1 genital slit.

Order Mysticeti (Baleen Whales)• Largest: Blue• 2nd largest: Fin • Humpback (sings)• http://www.oceanmammalinst.o

rg/songs/hmpback3.wav

• 2 Blowholes

Humpback

Minke Whale

Baleen

• Used for filter feeding• Grow down from upper jaw.

Rorqual• Many throat grooves• Shorter baleen plates

• Expand capacity of mouth

Diving Adaptations• Have 2x the RBC’s, and 9x

the myoglobin (than humans)

• Countercurrent heat exchange system

• Veins surround arteries; heat from blood in arteries is transferred to venous blood.

• Mammalian diving reflex- blood is shunted away from extremities to vital organs.

Gray Whale

Undertakes the longest migration (11,000 miles)

•

Order Odontoceti• Examples: Sperm,

Orca, Dolphins, Porpoises, Narwhal & Beluga

• Found in fresh and salt water

• Many toothed whales are countershaded or have disruptive coloration (killer whale)

• Sperm Whales have teeth in the lower jaw only!

• One Blowhole• No sense of smell in toothed whales

• Largest member of Dolphin family is Orca

• Largest toothed whale is the Sperm Whale

• Fastest is Dall’s Porpoise: 34 m.p.h.

Sperm Whale Dall’s Porpoise

Orca

Cooperative Hunting• Orcas, false killer whales, pilot whales, & bottlenose dolphins• Hunt in packs like wolves • Humpbacks use bubble netting to surround

their prey

Echolocation• Enables toothed whales

to locate and discriminate objects by listening for echoes

• Uses organ called a melon which contains fats

• Acts as an acoustical lens to focus sound waves out to H2O

• Sound travels 4x faster in H2O than in air.

• Lower jaw bones = sound reception