Marine mammals Characteristics of marine mammals: Warm-blooded Breathe air Have hair (or fur) can be minimized Bear live young Females have mammary glands that produce milk for their young, high in fat-- diluted

Marine mammals: Order Carnivora All members of order Carnivora have prominent canine teeth Includes: Sea otters Polar bears Pinnipeds (flipper-footed) Walrus Seals Sea lions/fur seals California sea lions Figure 14-17c

Differences between seals and sea lions/fur seals Lack visible ear flaps Have small front flippers Have claws Cannot rotate hind flippers beneath themselves Scoot on their bellies Figure 14-18

Differences between seals and sea lions/fur seals Have visable ear flaps Have large front flippers/Walk Have no claws 600- 2,200 lb Can rotate hind flippers beneath themselves Bark Loudly Walruses- no ear, can rotate flippers Figure 14-18

Marine mammals: Order Sirenia Sirenian characteristics: Large body size-- Thick skin Sparse hair all over body– Flat tail Vegetarians- Dense swollen bones Toenails (on manatees only) No ear flap, or hind limbs Live 70 years + Includes: Manatees Dugongs

Marine mammals: Order Sirenia Manatees Fresh or brackish water– Caribbean Flat tail No incisors- Split mouth 6 teeth Give birth @ 3, every 2-3 years– 12 months Dugongs Shallow bays, swamps, Egypt, Australia Fluke with points Nostrils farther back on head Tusks and solid/non-split mouth Give birth @ 10, every 3-5 years

Order Cetacea Cetacean characteristics: Blowholes on top of skull– Specialized muscles Skull telescoped (streamlined shape)- Fusiform body shape Very few hairs– No sebaceous glands Blubber Flat tails– Flukes Vestigial hind limbs Most have a dorsal fin Short neck– fused cervical vertebrae Bradycardia Organs go into Anaerobic respiration Low Surface area to Volume ratio- less exposed skin

Order Cetacea Extra capillaries in the lungs– Lungs collapse Use 3 times as much of the oxygen from a breath of air as do terrestrial mammals Can force almost all air out of the lungs when exhaling Twice as high a concentration of red blood cells 2-9 times as much myoglobin in muscle tissue Heart rate drops to half its normal rate during long dives During dives, blood is redistributed-- muscles High tolerance to lactic acid High tolerance to carbon dioxide No sinuses, or external ears Air is compressed- not liquid Excessive Hemoglobin, RBC (50%) and Myoglobin

Cetacea Champions Elephant seals – to 1500 meters, over 60 minutes, spend 90% of time at sea diving Emperor penguins – up to 500 meters Leatherback sea turtles – up to 1200 meters Sperm whales – up to 2032 meters, regularly staying down for 90 minutes Cuvier’s beaked whales – up to 2992 meters, stayed underwater 138 minutes

Marine mammals: Order Cetacea Figure 14-20

Two suborders of order Cetacea Suborder Odontoceti (toothed whales) Echolocation (send sound through water) Includes killer whale, sperm whale, dolphins, porpoises, and many others Sexual Dimorphism Teeth are conical or pointed- eat individual prey Melon on head- chamber filled with fluid Asymmetrical Skull Single Blowhole 3 part sternum

Two suborders of order Cetacea Suborder Mysticeti (baleen whales) Have rows of baleen plates instead of teeth, Keratin Includes blue whale, finback whale, humpback whale, gray whale, and many others Double blow hole Single boned sternum Batch feeders Long range migrations

Mysticeti: The baleen Mysticeti whales have baleen instead of teeth Baleen plates: Hang as parallel rows from the upper jaw Are made of keratin Are used as a strainer to capture zooplankton Allows baleen whales to eat krill and small fish by the ton

Baleen Figure 14-25

BALEEN

Families of Whales: Delphinidae— Cone teeth, larger central, dorsal fin, beak, Trash bag– dolphins and killer whales Phocoenidae—smaller, coastal, no beak, small dorsal fin Porpoise Physeteridae- Largest, spermaceti organ in square head, narrow jaw, head divided into “junk”, asymetrical Sperm whale Platanistidae- Long flat beak, external teeth, blind, echolocation, Ganges, Indus river, slit blowhole, unfused vertebrae, maxillary bone Balaenidae- Right, Bowhead, head is 1/3 body, neck completely fused, skimmers, finest, longest baleen, slow swimmers

Families of Whales: Balaenopteridae- Rorquals, largest ever, lunge feeders, throat grooves, set back dorsal fins, Fin, Blue whale, Humpback, Sei Eschrichtiidae– Gray whales, sift food off the bottom, intermediate group, coarsest and shortest baleen, knobs on the back, slight curve to the jaw Monodontidae– Small, no dorsal fin, artic, Narwhal Kogiidae- Pygmy sperm whale, smaller, square head, Platanistoidea: Superfamily- South Asian river Dolphin, Pink. Freshwater, 4 species Ziphidae– Reversed sexual dimorphism, beaked, 2 front teeth

Differences between dolphins and porpoises Dolphins have: An elongated snout (rostrum) A sickle-shaped (falcate) dorsal fin Teeth that end in points Killer whale jawbone Figure 14-22

Generation of Odontoceti echolocation clicks Figure 14-23

Odontoceti echolocation Sound is bounced off objects to determine: Size Shape Distance Internal structure Figure 14-24

Types of baleen whales Baleen whales include three families: Gray whale (a bottom-feeder with short baleen) Rorqual whales (medium-sized baleen) Balaenopterids (blue whales, finback whales, and other large whales ) Megapterids (humpback whales) Right whales (surface skimmers with long baleen)

An example of migration: Gray whales Gray whales undertake the longest annual migration of any mammal: Spend wintertime in birthing and breeding lagoons in Mexico Spend summertime feeding in highly productive Arctic waters Figure 14-27