Introduction to the Marine Mammals- Mammal- Any of various warm-blooded vertebrate animals of the class Mammalia, characterized by a covering of hair on the skin and, in the female, milk-producing mammary glands for nourishing the young.- Marine Mammalso Have similar adaptations for the marine environment Body Size Streamlined Shape Insulation- Dense fur or blubber Modified skeleton- Shortening of appendages- Loss of hind limbs Similar Physiological Adaptations- For diving, thermoregulation, osmoregulation, communication and orientationo Have similar habitat requirements Require the aquatic habitat for survival- They can therefore be used as indicators of habitat degradation.o Many have been exploited by humans to the point of near extinctiono Three Orders Carnivora- The mammalian carnivores, includes cats and dogs - Suborder Pinnipedia (‘fin’-‘footed’)o Most marine of the Carnivorao Use fat and/or fur for insulationo Deep diverso Must return to land in order to give birtho Family Otariidae Sea lions and fur seals The “Eared Seals” Hind flippers rotate under the body to permitwalking or running on land Swim by using the large fore flippers Dense fur that consists of long, coarse hairs and thick underfur in which air is trapped to promote insulation Tend to have a temperatue-to-subtropical distributiono Family Phocidae True Seals Lack ears, sometimes called “earless seals” Unable to rotate the hind limbs forward under the body and therefore don’t move well on land. Swim by using the hind flippers. Small pectoral flippers are used for steering. Blubber is used for insulation Excellent diving abilities Phocids are relatively large compared to Otariids Phocids are found throughout the world’s oceanso Family Odobenidae Walruses One species, Odobenus rosmarus] Large tusks Can rotate hind flippers under the body Use both front and hind flippers to swim No external ear Naked skin with only a few sparse hairs- Other Marine Carnivora o Family Ursidae Polar Bears Found only in the Arctico Family Mustelidae Otters- Sea otters of the pacific coast of N.America and Russia- Marine Otter of Chile and Peru Extremely dense fur Flattened hind feet for propulsion in water Axillary flap of skin to hold or store food and tools Horizontally flattened tail Cetacea- Whales dolphins and porpoises- Evolved from ariodactyls, even-toed ungulates such as cows or pigs- All are large, ranging from 2m to >30m- Streamlined body form with minimal protuberances that could cause drago Ex: They all lack external ears, reproductive organs,appendages and are generally hairless Vestiges of the pelvic girdle Some have hair during fetal development- Elongated skull with overlapping bones- Dorsal positioning of the blowhole- Subdermal blubber that can be 10’s of centimeters thick.- Porous, oil-filled bones- Multiple stomach compartments- 78 living species in two suborderso Mysticeti (baleen whales) Have baleen- a keratin-based brushlike adaptation suspended from the upper jaw Dorsally symmetrical skull Two blowholes Non fused mandible Tend to be large- Smallest mystecete, the Pygmy RightWhale is >6m Family Balaenidae- 4 Species:N. and S. right Whale, Bowhead and Pygmy Right Whale- Extremely convex profile of upper surface of skull- No dorsal fin- No gular grooves Family Balaenopteridae- 6 species: Blue, Fin, Sei, Bryde’s, Minke and Humpback- Flat profile to skull- Small triangular dorsal fin- Numerous gular grooves run from the snout to umbilicus Family Eshrichtiidae- 1 species: Gray whale- slightly convex profile to skull- no dorsal fin: aseries of ‘Knuckles” above the audal peduncle- 2-4 short gular grooves: benthic feedero Odontoceti (toothed whales) Possess teeth in one or both jaws. Dorsally asymmetrical skull A single blowhole Fused mandible Vary in size - Some dolphins are <2m- The sperm whale is 18m Family Physeteridae- 3 Species: Sperm whale, Pygmy and Dwarf sperm whale- Dorsal hump or small dorsal fin- Large bulbous head with spermaceti organ- Flukes notched- Well developed conical teeth in lower jaw only, fit into sockets in upper jaw Family Ziphiidae- 18 species: Beaked whales- 2 gular grooves- Small dorsal fin- Slender rostrum (beak)- Flukes not notched- 1-2 pairs of teeth confined to lower jaw Family Monodontidae- 3 Species: Beluga, Narwal, and Irrawaddy Dolphin- Generally no dorsal fin or small dorsal fin- Head blunt, no beak- Flukes notched- All cervical vertebrae free Family Platanistidae- 5 Species: River Dolphins- Small dorsal fin- Jaws form a long beak- Flukes notched- Many well developed conical teeth in both jaws Family Delphinidae- 32 Species: Dolphins, including the Orca- Large dorsal fin (except right whale dolphin)- Jaws form a beak or head gibbose (hump)- Flukes notched- Well developed conical teeth in both jaws or in lower jaw only Family Phocoenidae- 6 Species: Dorsal fin large and triangular- Head blunt, no beak- Well developed to poorly developed spatulate teeth in both jaws Sirenians- Manatees and Dugongs- Evolved from elephants and other subungulates- Skin lacks hair- Well developed vibrissae (whiskers)- Well developed layer of fat- Pectoral limbs modified as flippers- Hind limbs absent- Tail modified into flukes- Ears absent- Family Dugongidaeo 1 Species Dugong dugono Nails absento Tail modified into notched flukeso Male and female approximately the same size- Family Trichechidaeo 3 Species of Manateeo Vestigial nails presento Tail modified into rounded paddleo Male and female approximately the same