Marine mammals

1. 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

2. 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

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

4. Differences between seals and sea lions/fur seals • Sea Lions: • 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

5. 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

6. 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

7. 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

8. 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

9. 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

10. Marine mammals: Order Cetacea Figure 14-20

11. 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

12. 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

13. 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

14. Baleen Figure 14-25

15. BALEEN

16. 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

17. 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

18. 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

19. Generation of Odontoceti echolocation clicks Figure 14-23

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

21. 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)

22. 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