Marine Mammals PDF

Marine Mammals  Marine mammal A marine mammal is a mammal who lives in a marine environment (or in some cases an aquatic environment) and obtains all or most of its food there.  What does it mean to be a mammal? 1. They have lungs and breath air. 2. They are warm blo...

Marine Mammals  Marine mammal A marine mammal is a mammal who lives in a marine environment (or in some cases an aquatic environment) and obtains all or most of its food there.  What does it mean to be a mammal? 1. They have lungs and breath air. 2. They are warm blooded and maintain a constant body temperature. 3. Most give birth to live young. One primitive mammal group, the Monotremes (which includes the duckbill platypus and the echidna) lays eggs. 4. They produce milk and nurse their young. 5. They have hair at some point in their lives. Name some marine mammals:  For animals that live in the seas and oceans, those that meet all five criteria certainly include seals, sea lions, walruses, sea otters, polar bears and manatees. But what about dolphins, whales and porpoises? Hair? Yes, very early in life these animals posses hair around their mouths which are usually lost soon after birth.  There four general types of marine mammals 1. Cetaceans - whales, dolphins and porpoises 2. Pinnipeds - seals, sea lions and walruses 3. Sirenians - dugongs and manatees 4. Other/Carnivores - sea otters and polar bears Cetaceans - whales, dolphins and porpoises Pinnipeds - seals, sea lions and walruses  Sirenians - dugongs and manatees While manatees have a paddle-shaped tail. the dugongs have a tail that is pointed on the ends, very much like a whale's. Orca (Killer whale) Bottlenose dolphin Carnivores - sea otters and polar bears 1. CETACEA Whales and Dolphins come from the same family, CETACEA (sey-tay-sha) There are about 80 kinds of whales and dolphins that we know of right now.  What do whales and dolphins have in common? They both breathe from a blowhole located at the top of their head. Minke whale  Whales and dolphins are mammals They are mammals because they have: lungs not gills they have hair not scales they also give live birth and don't lay eggs.  There are two major groups of whale: 1.Toothed whales (suborder Odontoceti) 2. Baleen whales (toothless) (suborder Mysticeti). orca  Toothed Whales Toothed whales include several families a) the beaked and bottlenose whales (family Ziphiidae) b) the sperm whale (family Physeteridae); Point of interest: The white whale Moby-Dick, of Herman Melville's novel, was not a beluga but an albino sperm whale Bottlenose whale Beaked whale Sperm Whales have the largest "nose" in the animal kingdom. The nose contains an oil filled case which scientists believe the animal uses to produce and focus sound c) the beluga, or white whale, and the narwhal (family Monodontidae), narwhal beluga beluga d) small polar whales with no dorsal fin and only a few teeth; the river dolphins (family Platanispidae), River dolphins inhabit muddy rivers of India and South America; e) ocean dolphins and porpoises (there are several families), the killer whale and pilot whale are types of dolphins.  Pilot whales Killer whale  Echolocation Many species use echolocation (sonar) for underwater navigation and hunting. They have a single blowhole and a wide throat to accommodate large prey.  Toothless Whales There are three families of baleen whales 1) The right whale family (Balaenidae), including the bowhead, or Greenland whale; We can now use radio telemetry to find out where whales go… The North Atlantic Right whale’s north-south migration between calving and feeding grounds hugs the coast, setting up dangerous intersections with intensive east-west ship traffic through busy East Coast ports. Ship collisions are a major factor causing the right whale’s population decline. 2) the gray whale family (Eschrichtidae) With a single species (Eschrichtius robustus) found in the North Pacific Ocean; 3) the rorqual family (Balaenopteridae) This group includes: humpback whale sei whale minke whale Bryde's whale the fin whale (or common rorqual) the blue whale (which can grow to a length of 100 ft (30 m) and a weight of 150 tons) humpback Dwarf minke whale humpback Sei whale Fin whale Bowhead whale  Baleen Plates Baleen whales use their mouth as a giant strainer. The upper jaw is lined with bony plates called baleen that hang vertically like vertical blinds. The spaces between the plates are small allowing water to pass through, but not the food.  Baleen Plates The whale swims through the schools of fish with its mouth open taking in both fish and water. The throat pleats expand to make more room. Then the whale closes its mouth and pushes the water out through the baleen plates trapping the fish inside to be swallowed.  Toothless whales are large species, usually over 33 ft (10 m) long. They are filter feeders, living on shrimp like krill, plankton, and small fish. They lack teeth but have brushlike sheets of a horny material called baleen, or whalebone, edging the roof of the mouth Blue Whales are the largest to have ever lived on the planet at a recorded length of more than 110 feet and a weight of around 190 tons 2) Pinnipeds “winged feet" aquatic mammals that use flippers for movement on land and in the water they are carnivores All pinnipeds must come ashore to breed, give birth, and nurse their young Three families of living pinnipeds are recognized: 1. Earless seals or true seals (Phocidae) 2. Eared or fur seals and sea lions (Otaridae) 3. Walruses (Odobenidae)  SEALS: Do not have an ear that extends from the skull, but they can still hear well. Propel themselves through the water with their rear flippers. Front flippers are used for steering. The front flippers of seals are short with sharp claws. Seals cannot use their rear flippers to walk on land or ice and most appear awkward when moving on these surfaces. Seals have a torpedo like shape in the water and use their rear flippers to move rapidly to catch prey and escape predators. Largha (spotted) seal Crabeater seals Crabeater seal skull with blowup of the special teeth that are used to filter the krill from the water Ribbon seal Harbor seal Spotted seal  Sea Lions and Fur Seals Fur seals and sea lions have ears that extend from the skull. The front flippers of fur seals and sea lions are used to propel them through the water. Sea lions are the larger of the two. Sea lions have a rounded snout and their fur is coarse and shorter than a fur seal. Fur seals have a longer, pointer snout, their fur is longer and finer, and their flippers are longer. Steller sea lion Northern fur seal pup Northern Fur Seal pup Steller Sea Lion pups Northern Fur Seal Bull. Notice the thick fur, the fur is thick enough that it is waterproof Galapagos Sea Lion Walrus The Walrus lives in the Arctic circle and spends much of its day in open water or near the shore resting on ice floes Sometimes the blubber on a walrus will be over 6 inches deep to keep the animal from freezing to death 3) Sirenians-Manatees and Dugongs Sirenians spend their whole lives in water. Manatees are aquatic mammals that are called sea cows (named this by Georg Wilhelm Steller, because they taste like beef). These plant eaters are slow swimmers; they have two flippers, each of which has three to four nails on the end (there are no external hind limbs). Short whiskers adorn the short, boxy snout. Manatees are closely related to the elephant  Manatees migrate along the coast. North American manatees winter in Florida, as they prefer warm water. Amazonian manatees Antillean manatee Florida manatee  Dugongs The dugong lives in the shallow water of tropical seas off the coasts of East Africa, Australia, India, the Philippines, and other islands in the South Pacific. Dugongs look different from manatees. Dugongs have pointed tails ( many manatees have a small notch in the tail) and one pair of tusk-like teeth. Dugongs are seldom found in freshwater.  Dugong Dugongs rest in the deep water during the day and move towards the shoreline at night to feed. The dugong uses its flippers for balance and moving along the ocean floor as it grazes. Dugongs are not thought to migrate as far as the manatees do. Like manatees, dugongs are usually found in small groups are alone. But groups of thousands of dugongs have been seen occasionally. dugong or sea cow dugong or sea cow 4) Other Marine Mammals (Carnivores) Two species that are also considered marine mammals are the Northern Pacific sea otter and the South American sea otter. Sea otters are notable because they are the only marine mammal species that use tools to forage for food. Sea otter Sea otter  Polar bear The polar bear is also considered a marine mammal because it is a proficient swimmer, which hunts primarily on sea ice for ringed and bearded seals. Marine mammals unique to the waters of the circumpolar Arctic, and found in the wild in five countries: Canada, Greenland (territory of Denmark), Norway, the USA, and the former USSR, as well as on the high seas where jurisdiction is not clearly defined. Polar bears current wild population of Polar bears is estimated to be between 21,000 and 28,000 individuals. The average land Polar bear is 2.5 to 3 metres long. Males grow to 2 or 3 times the size of females. Tomorrow’s Lab (Wear shoes)