Marine Mammals B.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 Mammals B.Order Pinnipedia 1.Seals (19 Species) Rear flippers can’t be rotated forward Swim with rear flippers Video VideoVideo 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 LeopardCrabeater Harbor S. Elephant Video

Marine Mammals B.Order Pinnipedia 2.Sea Lions (5 species) Rear flippers can be rotated forward Swim with front flippers Video VideoVideo Rotate limbs and can walk on land External ears 3.Fur Seals (9 species) Related to sea lions Formerly hunted for fur

Marine Mammals B.Order Pinnipedia

Marine Mammals B.Order Pinnipedia 4.Walrus (1 species) Feeds on benthic invertebrates, mostly clams Tusks used for defense or as anchors in ice

Marine Mammals B.Order Carnivora 1.Sea otter (1 species) Smallest marine mammal (average male 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 Mammals B.Order Carnivora 1.Sea otter (1 species)

Marine Mammals B.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 Mammals C.Order Sirenia Manatees, Dugongs and Seacows Front flippers, no rear limbs Swim mainly with tail VideoVideo Thick blubber layer Strictly vegetarian Manatees reach 4.5 m, 600 kg Major threats from coastal development and boat traffic

Marine Mammals C.Order Sirenia

Marine Mammals C.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 Mammals C.Order Cetacea Blubber Blowhole on dorsal surface

Marine Mammals C.Order Cetacea 1.Mysticeti (Baleen Whales) – 11 species Baleen plates attached to upper jaws Made of keratin

Marine Mammals C.Order Cetacea 1.Mysticeti (Baleen Whales) – 11 species

Marine Mammals C.Order Cetacea 1.Mysticeti (Baleen Whales) – 11 species

Marine Mammals C.Order Cetacea 1.Mysticeti (Baleen Whales) – 11 species a.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 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 Mammals C.Order Cetacea 1.Mysticeti (Baleen Whales) – 11 species

Marine Mammals C.Order Cetacea 2.Odontoceti (Toothed Whales) – 66 species Teeth adapted for a different diet Only have 1 blowhole

Marine Mammals C.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 Mammals C.Order Cetacea 2.Odontoceti (Toothed Whales) – 66 species b.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 Mammals C.Order Cetacea 2.Odontoceti (Toothed Whales) – 66 species b.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 Mammals C.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 Mammals C.Order Cetacea 3.Status

Marine Mammals D.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 Mammals E.Echolocation Common in dolphins, porpoises, toothed whales May occur in some baleen whales and pinnipeds DolphinsWhales