Phylum Chordata

1. Phylum Chordata (Sea Otters and Polar Bears) Kellsie M. & Rachel R.

2. Taxonomic Classification Domain – Eukarya Kingdom – Anamalia Phylum – Chordata Class – Mammalia Order – Carnivora Family –Ursidae (Bear) & Mustelidae (Sea Otter) Genus – Enhydra (Sea Otter) & Ursus (Polar Bear) Species – lutis (Sea Otter) & maritimes (Polar Bear) Enhydra lutis Ursus maritimus

3. Key Characteristics • Polar Bears • Their fur is thicker than other bears and it covers their feet for warmth and traction on the ice • Thick layer of blubber beneath fur provides buoyancy and insulation • They have a long neck and narrow skull which helps aid streamlining in the water and their front feet are large, flat, and oar- like • They have canines and eat meat • Sea Otters • They have long, slim bodies with short limbs that have webbed paws • Sharp claws on all feet • Thick fur to keep warm because they have no blubber • Hind feet are long, flattened, and fully webbed- helps with swimming • They have a muscular tail

4. Adaptations/Physiology • Sea Otters • Use their feet to reduce or maximize heat loss when water temps are too hot or cold • When water temps are too cold they reduce heat loss by floating on their backs with their feet out of the water • They control their lung capacity to increase buoyancy in cold water and reduce lung volume to decrease buoyancy in warmer water • Their nostrils and ears can close • Also, their feet and tails are adaptations • Polar Bears • A polar bear's front paws propel them through the water dog-paddle style. The hind feet and legs are held flat and are used as rudders. • A thick layer of blubber (fat), up to 11 cm thick, keeps the polar bear warm while swimming in cold water. • A polar bear's nostrils close when under water • Body temperature, which is normally 98.6°F, is maintained through a thick layer of fur, a tough hide, and an insulating fat layer . This insulation keeps a polar bear warm even when air temperatures drop to -34°F. • Polar bears are so well insulated they tend to overheat

5. Habitat • Sea Otters • Live in the Pacific Ocean • Range from Soviet Union to California • Generally live in fairly shallow waters, the deepest waters being 40m • habitat is composed of the sea floor where they catch food and the sea surface where they eat, groom, rest and socialize • Sea otters will frequently live in areas which have kelp beds • Polar Bear • Polar bears are found throughout the circumpolar Arctic along or near coasts, on islands and on sea ice. • The polar bears live in areas where sea ice meets water to hunt seals that make up majority of its diet • Some polar bears retreat each summer to the ice further north that remains frozen year-round.

6. Reproduction • Sea Otters • Most don't successfully reproduce until they are five to seven years old. • Female sea otters become mature at about four years. Males are capable of mating at age five or six, but usually don't become active breeders for several more years. • Sea otters breed throughout the year. Males may breed with more than one female during the year. • Polar Bears • Males seek out females by following their scent. Two males may fight over a female. • Females begin to mate around the ages of 4 or 5. Males take longer to mature and usually begin attempts to mate around the age of 5 or 6, though their prime breeding years begin around age 10

7. FUN FACTS! • Polar Bears • Female polar bears would rather build their dens in "old snow" from previous years rather than the freshly fallen snow. • Polar bear cubs learn to freeze and remain still while their mother hunts. If they move, the mother disciples them with a whack to the head. • Paw pads with rough surfaces help prevent polar bears from slipping up on the ice. • A polar bear's fur is not white! It is hollow. The fur reflects light. The hollow fur also traps the suns heat to help keep the polar bear warm. • Sea Otters • Otters live on every continent except Antarctica and Australia. • The sea otter’s fur is the finest and densest of any animal fur. • The sea otter is the smallest marine mammal. • Sea otters are the only tool using mammal. • An otter’s coat has pockets, flaps of skin under their front legs. Otter use them to hold their captured food until they return to the surface

8. Sources • Book • Wikipedia • http://bioweb.uwlax.edu • http://www.seaworld.org/animal-info/info-books/polar-bear/adaptations.htm • http://www.bio.davidson.edu/Courses/anphys/2000/Boehm/Habitats.html