Marine Mammals

1. Marine Mammals Kingdom Animalia Phylum Chordata Class Mammalia www.nhs.stjohns.k12.fl.us/teachers/nalld/.../unit%2016%20mammals.ppt

2. Marine Mammal characteristics • All mammals share the following characteristics: • Hair • Nurse young (mammary gland) • Breathe air • Warm blooded • Live birth

3. 5 groups of marine mammals • Seals, Sea lions & Walruses • Sea otters • Polar bears • Whales and Dolphins • Manatees

4. Order Carnivora • SubOrder Pinnepedia • Seals, Sea Lions, Walruses • Characteristics: • Pinneped means fin footed • Excellent swimmers • Thick layers of blubber to protect from cold • Make a barking sound • Nostrils can close for diving • Diet of mainly krill, crustacians, mollusks, fish, and squid

5. Seals • Seals (earless pinnipeds; family Phocidae) have 19 representative species • Rear flippers cannot be moved forward • No external ear flap • Claws (and fur) on flippers • Short, robust neck Photograph is property of the Riverhead Foundation

6. Crabeater seal

7. Weddell seal

8. Leopard seal Crabeater seal

9. Sea lions and fur seals vs. Seals Sea lions and fur seals (Otariidae) Seals (Phocidae)

10. Sea lions and fur seals • Sea lions and fur seals (eared pinnipeds; family Otariidae) have 15 representative species • Rotatable hind flippers • External ear flap • Long, flexible neck • No fur or claws on flippers

11. New Zealand fur seal

12. Pinnepeds • Family Otariidae - eared seals include sea lions and fur seals. • Can rotate both pectoral & pelvic fins to “walk” on land

13. Pinnepeds • Family Phocidae - are true seals. • They have no visible ear flap. • No hind leg rotation • Front legs cannot support their weight • Because they must drag their back fins they are easy prey

14. Pinnepeds • Family Odobenidae - walruses • found only in North Polar regions. • Use tusks to hoist themselves onto the ice and to dig for clams • Nearly became extinct due to humans killing them for their ivory tusks

15. Most pinnepeds (except walruses) are covered with dense, waterproof fur that was attractive to man. • Since the Marine Mammal Protection Act of 1972, hunting is illegal • As a result the shark has also experienced an increase in population because it’s food source is readily available.

16. Sea Otters • Family Mustelidae • Smallest of the marine mammals • Four functioning limbs • Have no blubber • Fur is dense and protects from cold • Otter pups can’t swim so they float or rest on the mother’s stomach. • Use tools such as rocks to break abalone • Use kelp to anchor themselves and young

17. Polar bears • Family Ursidae • Only recently added to marine mammal list • Extreme amounts of blubber • Fur is transparent • Skin is black • Feet look like snowshoes and are webbed • Cover their nose when hunting as not to be detected.

18. Polar bear Diet Polar bears feed mainly on ringed and bearded seals. Also eat harp and hooded seals and scavenge on carcasses of beluga whales, walruses, narwhals, and bowhead whales. On occasion, polar bears kill beluga whales and young walruses. When other food is unavailable, polar bears will eat just about any animal they can get, including reindeer, small rodents, seabirds, waterfowl, fish, eggs, vegetation (including kelp), berries, and human garbage. (http://www.seaworld.org/animal-info/info-books/polar-bear/diet.htm)

19. Order Cetacea Blue whale Dolphin • Whales, dolphins, and porpoises • Grouped by their mouth structures • Family Mysteceti - baleen whales • Family Odontoceti - toothed whales

20. Family Mysteceti • Possess baleen to strain plankton • Ex. right, humpback, blue • 2 nostrils and 2 blow holes • Eat large amount of food that is low on the food chain • Dorsal fin is reduced in size or absent in larger whales Right whale Right Whale Sperm whale

21. Family Odontoceti • Known as toothed whales because of their conical shaped teeth • Ex: sperm whale, orca, dolphins • 2 nostril but only 1 blow hole Porpoise

22. Cetaceans are protected by the Marine Mammal Protection Act of 1972. This act made whaling illegal in US coastal waters • Many are still being hunted under the guise of scientific research or are “by-catch” of the tuna fishery • The International Whaling Commission (I.W.C.) is a whalers organization that sets quotas based on catch size. • Problems with the IWC is that it is strictly voluntary and actual is set to protect the whaling industry not the whales.

23. Cetacean adaptations • Swimming - use powerful tail flukes • Fluke markings are used like fingerprints for identification • Digestion - multi-compartmentalized stomachs “chew” food. • Even toothed whales don’t chew their food • Baleen whales eat krill and plankton • Toothed whales eat fish, penguins, seals… Bowhead Right whale Grey whale Narwhal

24. Cetacean adaptations • Circulation - 4 chambered heart • Blubber insulates against the cold. • Possess counter current heat exchange which keeps the whale from overheating. • Can transfer arteriole heat to surface tissues (flukes and fins) • Senses - vision is poor, uses echolocation to compensate

25. Cetacean adaptations • Whales have no vocal chords but make clicks and whines by vibrations in the blow hole • Sounds are emitted and amplified in the head through an oil filled cavity called a melon • Incoming vibrations are focused through the jaw and melon to the inner ear and the brain

26. Cetacean adaptations • Diving - lungs are emptied and filled quickly through blow hole on top of head • A trachea under the blow hole connects directly to lungs • Nasal passages close when relaxed to prevent water from entering the lungs • Oxygen is stored in muscles, ribs are collapsible to reduce internal air pockets • Whale strandings occur when they are ill to prevent drowning

27. Cetacean adaptations • Excretory - specialized kidneys allow whales to drink salt water. Urine has high salinity content • Reproduction - internal • Mating occurs in early summer, gestation lasts 7 months so the egg implantation is delayed 4 months so that the baby is born in the warm summer months • Most whales have 1 calf every 2-3 years • Whale milk is unusually high in fat content

28. Whale migrations • Are timed to coincide with • Weather • Mating • Migrations of other fish • Births Orca Pilot whale Humpback

29. Order Sirenia • Manatees or Sea cows • Protected by the state of Florida since 1893 • Protected by the Endangered Species Act of 1973 • Protected by the Marine Mammal Protection Act of 1972 • BUT ONLY AROUND 1200 STILL SURVIVE TODAY

30. Family Dugongidae Dugong Found in Australia and Indonesia Notched tail fluke Stellar Sea Cow Hunted to extinction within 27 years of its discovery in 1741 Family Trichechidae West Indian manatee Found from Florida to Brazil Round paddle shaped tail Amazonian manatee West African manatee 5 populations in the Order Sirenia

31. Manatees • Manatees are related to the elephant through biochemistry and external features • Average 10’ in length and weighs ~ 1000lbs • Use blubber to keep warm • Herbivores that may eat 100 lbs of sea grass a day

32. Manatee characteristics • Their constant eating helps keep channels clear. Ironically this causes 50% of deaths due to careless boaters. • Manatees must surface to breathe • Whiskers (vibrissae) on snout used to rake in plants • Nurse young for a year. Mammary glands are located under flippers

33. Manatee characteristics • Live birth - gestation period of 13 months • Produce 1 calf ever 3-5 years • Large brain, poor vision • Warm blooded with 4 chambered heart • Stomach has compartments, it ruminates (chews its cud) • Breathes air - may dive for 20 minutes • Tail - horizontal paddle • Can produce high pitched whistle for communication

34. Manatee characteristics • Because they have no predators • they have no social structure, • not territorial, • herds don’t have a leader, • no permanent bonds are formed for mating