Marine MammalsB. Order Pinnipedia

• Evolved from terrestrial carnivores• Predators - Fishes, squids• Streamlined bodies• Blubber layer under skin• Inhibit loss of body heat through

• Large body size (low surface:volume)• Bristly hair

• Many nest in rookeries• Males establish territories and harems

Marine MammalsB. Order Pinnipedia

1. Seals (19 Species)• Rear flippers can’t be rotated forward

• Swim with rear flippers Video Video

• Undulate body to move on land

• Include largest pinniped

• Elephant seals can reach 20 ft long and 3600 kg

• Threatened by hunting and coastal development

Weddell

Leopard Crabeater

Harbor

S. Elephant

Video

Marine MammalsB. Order Pinnipedia

2. Sea Lions (5 species)• Rear flippers can be rotated forward

• Swim with front flippers Video Video

• Rotate limbs and can walk on land

• External ears

3. Fur Seals (9 species)• Related to sea lions

• Formerly hunted for fur

Marine MammalsB. Order Pinnipedia

Marine MammalsB. Order Pinnipedia

4. Walrus (1 species)• Feeds on benthic invertebrates, mostly clams

• Tusks used for defense or as anchors in ice

Marine MammalsB. Order Carnivora

1. Sea otter (1 species)• Smallest marine mammal (average male 25-35 kg)

• No blubber layer

• Insulation from air trapped in dense fur

• Keystone predators in west coast kelp forests

• Voracious – Eat up to 25% of body weight daily

Marine MammalsB. Order Carnivora

1. Sea otter (1 species)

Marine MammalsB. Order Carnivora

2. Polar bear (1 species)• Semiaquatic

• Considerable time in water

• Feed primarily on seals

• Capture prey through breathing holes in ice

• Impacted by climate change

Marine MammalsC. Order Sirenia

• Manatees, Dugongs and Seacows

• Front flippers, no rear limbs• Swim mainly with tail Video

• Thick blubber layer

• Strictly vegetarian

• Manatees reach 4.5 m, 600 kg

• Major threats from coastal development and boat traffic

Marine MammalsC. Order Sirenia

Marine MammalsC. Order Cetacea

• Whales, dolphins, porpoises• 90 species – 85 marine, 5 freshwater (dolphins)

• Front flippers, tail, no rear limbs

• Streamlined for efficient swimming• Example of convergent evolution

Marine MammalsC. Order Cetacea

• Blubber

• Blowhole on dorsal surface

Marine MammalsC. Order Cetacea

1. Mysticeti (Baleen Whales) – 11 species• Baleen plates attached to upper jaws

• Made of keratin

Marine MammalsC. Order Cetacea

1. Mysticeti (Baleen Whales) – 11 species

Marine MammalsC. Order Cetacea

1. Mysticeti (Baleen Whales) – 11 species

Marine MammalsC. Order Cetacea

1. Mysticeti (Baleen Whales) – 11 speciesa. Rorqual whales – 6 species

• Bryde’s, Blue, Fin, Humpback, Minke, Sei• Large blue whales may enclose up to 17,500 gallons (70 tons) of water in one gulp• Blue whales eat 3000-5000 kg of food each day!• Short baleen, small dorsal fin, ventral grooves

b. Right whales – 4 species• Bowhead, Northern Right, Southern Right, Pygmy Right• Long, fine baleen, no dorsal fin, no ventral grooves

c. Gray whale – 1 species• Short coarse baleen, no dorsal fin, 2-5 ventral grooves

Marine MammalsC. Order Cetacea

1. Mysticeti (Baleen Whales) – 11 species

Marine MammalsC. Order Cetacea

2. Odontoceti (Toothed Whales) – 66 species• Teeth adapted for a different diet

• Only have 1 blowhole

Marine MammalsC. Order Cetacea

2. Odontoceti (Toothed Whales) – 66 species• Teeth adapted for a different diet• Only have 1 blowhole

a. Sperm whales – 3 species• Sperm, Dwarf Sperm, Pygmy Sperm• Bulbous head contains spermaceti (waxy substance) that may function

in buoyancy and sound generation• Sperm can dive to 3000 m and stay under water for up to two hours!• Feed on fishes and squids, esp. giant squids• Produce ambergris, undigested material in stomach

Marine MammalsC. Order Cetacea

2. Odontoceti (Toothed Whales) – 66 speciesb. Toothed whales – 30 species

• Beaked, Beluga, False Killer, Narwhal, Orca, Pilot

• Most common in cold water

c. Dolphins & Porpoises – 33 species

• Distinctive beak

• Travel in pods

Marine MammalsC. Order Cetacea

2. Odontoceti (Toothed Whales) – 66 speciesb. Toothed whales – 30 species

• Beaked, Beluga, False Killer, Narwhal, Orca, Pilot

• Most common in cold water

c. Dolphins & Porpoises – 33 species

• Distinctive beak

• Travel in pods

Marine MammalsC. Order Cetacea

3. Status• Whales hunted extensively for centuries

• Aboriginal whaling (Eskimos)• Non-aboriginal whaling

• Began off New England by late 1600s• 1860s – Explosive harpoon introduced• Early 1900s –Antarctic whales hunted• 1946 – IWC founded• 1972 – US Marine Mammal Protection Act• 1985 – IWC moratorium on commercial whaling• Norway, Japan, Iceland still practice whaling

• IWC allows aboriginal whaling

Marine MammalsC. Order Cetacea

3. Status

Marine MammalsD. Diving

• Adaptations for long and deep dives

1. High hematocrit

2. Muscles rich in myoglobin

3. Reduction of heart rate

4. Flexible rib cage

5. Majority of oxygen in blood and tissues

Marine MammalsE. Echolocation

• Common in dolphins, porpoises, toothed whales • May occur in some baleen whales and pinnipeds

Dolphins Whales Whales