1. Common Characteristics
2. Classification
3. Carnivora
4. Sirenia
5. Pinnipeda
6. Cetacea

Common Characteristics

1. Warm blooded
2. Placental development and live birth
3. Milk production
4. Air breathing with lungs

Four Order Classification

1. Order Carnivora
2. Order Sirenia
3. Order Pinnipeda
4. Order Cetacea

Sea Otters

1. Sea Otters belong to the family Mustelidae which contains weasels, minks, ermines, and otters.

Anatomical Features

1. Four paws and laterally compressed tail
2. 3-4 feet long
3. Thick, dense fur
4. Lack blubber

Metabolism

1. Require a high metabolic rate to keep warm
2. Consume 25 percent of body weight in food each day

Feeding

1. Eat echinoderms, mollusks, crustaceans, and fish
2. Especially urchins and abalones

Special Behavior

1. Float on back
2. Anchor to kelp
3. Use a rock anvil to crack shellfish

Ecology

1. Inhabit kelp beds on Pacific shores
2. Help kelp by controlling urchin numbers (urchins eat young kelp)

Sea Cows

1. Sirenians: Atlantic Manatees and Indo-Pacific Dugongs

Anatomical Features

1. Lack rear limbs
2. Horizontally broad tail provides thrust in swimming
3. Grow up to 10 feet long
4. Good hearing and poor eyesight

Feeding

1. Eat aquatic plants
2. Have complex stomachs like the land dwelling ruminants

Special Behavior

1. Whistle to communicate
2. Can dive for up to 20 minutes

Ecology

1. Live in rivers, estuaries, sea grass meadows, and in coral reef lagoons

Seals, Sea Lions and Walruses

1. Pinniped means winged feet

Anatomical Features

1. Four limbs modified as flippers
2. Small tail

Feeding

1. Carnivorous
2. Most feed on invertebrates (especially squid) and fish
3. Leopard seals eat other pinnipeds and penguins

Special Behavior

1. Breeding colonies
2. Polygynous with each breeding male servicing many females

Ecology

1. Most abundant in temperate and polar waters
2. Amphibious
3. Can remain at sea for months
4. Must return to land to breed

Families of Pinnipeds

1. Otaridae are fur seals and sea lions
2. Odobenidae are walruses
3. Phocidae are true or hair seals

Sea Lions

1. External ears
2. Hind flippers can be turned under body for walking on land
3. Long, partly bare fore flippers which lack claws
4. Use fore flippers as paddles and rear flippers to steer

Walruses

1. No external ears
2. Nearly hairless skin
3. Hind flippers can be turned under body for walking on land
4. Upper canine teeth are modified into long tusks in both sexes

True Seals

1. No external ears
2. Small rear flippers can't be turned under body (wiggles on land)
3. Small, furred fore flippers with 5 claws
4. Use rear flippers as paddles and fore flippers to steer

Whales, Dolphins, Porpoises

1. Cetaceans are an ancient group

Anatomical Features

1. Streamlined shape
2. Lack rear limbs
3. Have blowholes (nostrils) on top of head
4. Tail modified as broad horizontal fluke

Evolution

1. Evolved from a 4-limbed terrestrial ancestor
2. Adult has vestiges of pelvic girdle

Fetus Reveals Ancestry

1. Four limb buds
2. Pelvis
3. Nostrils at front of head

Breathing

1. Puffing
2. Powerful diaphragm and rib cage musculature
3. Blow and inhale rapidly
4. Turnover most of lung volume in each breath

Blowholes

1. Musculature opens blowholes upon contraction
2. Contain nasal plugs involved in sound production

Breathing Pattern

1. Blow 2 to 7 times, then dive for 4 to 20 minutes
2. Fewer breaths per minute than terrestrial mammals

Long Breath Holding Capacity

1. Large blood pool stores oxygen (greater blood:body volume)
2. Shunt blood and the oxygen it contains from the periphery, gut, and kidneys to the brain, heart, lungs, and muscles
3. Slow the heart rate and the circulation rate, increasing the amount of time the blood with its stored oxygen is in contact with the tissues
4. Muscle myoglobin binds oxygen and stores it

Rete Mirabile

1. Rete Mirabile are spongy masses of blood vessels
2. Regulate blood pressure with depth (external pressure)
3. Increased external pressure squeezes blood out of rete and increases circulating volume

Lactate Metabolism

1. Produces usable energy anaerobically (without oxygen)

Echolocation

1. Highly developed sense evolved because sound travels well in water
2. Air forced through passages in head vibrates nasal plug and produces sounds

Projection and Reception

1. Oil-filled melon focuses the transmitted sounds
2. The melon and lower jaw receive sounds and channel them to ears

Annual Migrations

1. Feed in polar waters in summer on plentiful plankton and fish
2. Calve in temperate and tropical waters in winter
3. Examples: gray whales, right whales, and humpback whales

Reasons for Migrating

1. Food is seasonally scarce in polar waters
2. Temperatures are better for survival of calves

   A. Calves have less blubber

   B. Calves have a higher surface-to-volume ratio (faster heat loss)

Gray Whale Migration

1. Gray whales migrate 5,500 miles from the Bering Sea to Mexico
2. Grays remain close to the shore, feeding on benthic invertebrates

Migration Pattern

1. Grays move south in September
2. The females lead the way
3. Grays move north in March and April

Reproduction

1. Female reproductive organs are similar to humans
2. Male reproductive organs differ from humans
3. Testes are located inside their body cavities
4. Penis retracts inside their body cavities

Copulation

1. Face to face, brief and difficult to maintain
2. Often assisted by another whale who stabilizes the couple

Gestation

1. Blue whale pregnancy lasts 11 months

Calf Growth Rates

1. Blue whale calves weigh 3 tons at birth and gain 100 kg/day
2. Blue whale calves weigh 23 tons at 7 months of age

Nursing

1. Blue whale calves drink 600 liters (over 1/2 ton) of milk each day
2. Cetacean milk is very rich being 25-50% fat
3. Blue whale calves are weaned at 7 months

Cetacean Suborders

1. Odontoceti are toothed whales
2. Mysticeti are baleen Whales

Toothed Whales

1. Teeth
2. One blowhole
3. Sophisticated echolocation

Dolphins

1. Pointed snout
2. Peg-like teeth
3. Dorsal fin curves to the posterior

Porpoises

1. Blunt snouts
2. Spade-like teeth
3. Dorsal fin is low and more triangular

Sperm Whales

1. Largest toothed whales, growing up to 40 or 50 feet long
2. Deepest divers of all whales

Feeding in Toothed Whales

1. Most feed on crabs, shrimp, squid, and fish
2. Killer whale eats pinnipeds and small whales as well

Baleen Whales

1. Baleen
2. Have two blowholes
3. Vocalize by singing intricate songs

Rorquals

1. Baleen whales with accordion-like pleats for expansion of throat

Blue Whale

1. Largest of all whales reaching 100 feet in length and weighing 170 tons

Feeding in Baleen Whales

1. Filter feeders that strain plankton, squid, and small fish from water
2. Gray whales strain crustaceans and annelids from sediments