Marine Mammals Class Mammalia Class Mammalia Tetrapods with

Marine Mammals Class Mammalia

Class Mammalia • Tetrapods with young nourished from mammary glands. • Hair on their body. • Endothermic. • Viviparous

Order Sirenia: Manatees and Dugongs • 1 species of dugong • 3 species of manatees

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

Order Carnivora • • • Well-developed claws. Strong facial musculature Specialized teeth: canines and incisors.

Suborder Pinnipedia: Sea Lions, Seals and the Walrus

Family Otariidae: Sea Lions

Family Phocidae: Seals

Comparison of Sea lions and Seals Sea Lions (Otariids) Seals (Phocids) • • External ears Long neck Performs in shows Use front flippers to swim • Can pull hind flipper under body to walk on land • Claws ¾ to end of flipper No external ears Short neck Do not perform Use back flippers to swim • Can’t rotate hind flippers • Claws at end of flippers

Family Odobenidae: Walrus • Both males and females have tusks. • Use vibrissae (whiskers) to feed.

Family Mustelidae: Sea Otter Two North American Subspecies 1. The Alaska / Northern 2. The California / Southern

Sea Otter Fur • Over 1 million hairs/in 2 (Humans have 20, 000 hairs on their entire head!) • Need thick fur because they have NO blubber • Oil on hair repels 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, abalone, crabs). • Use tools.

Polar Bears

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

Adaptations to the Arctic • Small ears which help conserve body heat. • Hind limbs are longer than forelimbs • 12’’ paws – act like snowshoes • Non-retractable claw (to grip ice) • Thick fur that 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

• No natural predators as adults • Threatened species protected under MMPA (Marine Mammal Protection Act)

Order Cetacea

• • Sub. Order Mysticeti (Baleen Whales) Largest: Blue 2 nd largest: Fin Humpback (sings) http: //www. oceanmammalinst. o rg/songs/hmpback 3. wav • 2 Blowholes Minke Whale Humpback

Baleen Plates • Used for filter feeding • Made of keratin like hair and nails

Rorqual • Throat grooves • These whales have shorter baleen plates • Expand capacity of mouth

Diving Adaptations • Have 2 x the RBC’s, and 9 x the myoglobin (than humans) • Countercurrent heat exchange system: Veins surround arteries; heat from blood in arteries is transferred to venous blood. • Mammalian diving reflexblood is shunted away from extremities to vital organs.

Gray Whale Undertakes the longest migration (11, 000 miles) •

Sub. Order Odontoceti • Examples: Sperm, Orca, Dolphins, Porpoises, Narwhal & Beluga

• • • Found in fresh and salt water One Blowhole No sense of smell in toothed whales

Whale Anatomy • Female whales have a genital slit and 2 mammary slits. • Males have 1 genital slit.

• 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 Orca Dall’s Porpoise

Cooperative Hunting • Includes orcas, bottlenose dolphins and humpbacks • 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 H 2 O • Sound travels 4 x faster in H 2 O than in air. • Lower jaw bones = sound reception