Sea Otters Dylan Pinzon 5-8-16 Period 2

Basic facts is a marine mammal native to the coasts of the northern and eastern North Pacific Ocean Adult sea otters typically weigh 31-99 pounds They’re the smallest of the marine mammals They sleep over kelp forests in which they entangle themselves to keep stationary through their sleep

Basic facts (continued) The sea otter propels itself underwater by moving the rear end of its body, including its tail and hind feet, up and down When at the surface, it usually floats on its back and moves by sculling its feet and tail from side to side Long, highly sensitive whiskers and front paws help the sea otter find prey by touch when waters are dark or murky

diet They prey on marine invertebrates Such as sea urchins, mollusks and some species of fish They're carnivores Due to their high metabolism they consume up to about 25% of their body weight They use rocks to crack open shells

Population They were once estimated at 150,000-300,000 Hunted for fur decreased the numbers to 1,000-2,000 in the early 1900s A ban on hunting, conservation efforts, and reintroduction programs into previously populated areas have contributed to numbers rebounding, and the species now occupies about two-thirds of its former range Oil spills also decreased their numbers They’d lose the ability to insulate themselves and their food source was damaged

Evolution The sea otter member of the family Mustelidae a diverse group that includes the 13 otter species and terrestrial animals such as weasels, badgers, and minks It is unique among the mustelids in not making dens or burrows, in having no functional anal scent glands Can survive without ever leaving water

Physical characteristics Male sea otters weigh between 49-99 pounds while females weigh 31-73 pounds Sea otters have no blubber and really on their fur to keep warm Their fur is the densest of any animal The hind feet, which provide most of its propulsion in swimming, are long, broadly flattened, and fully webbed The fifth digit on each hind foot is longest, facilitating swimming while on its back, but making walking difficult

behavior Sea otters spend most of their timing cleaning their fur This includes cleaning the fur, untangling it, removing lose hairs and drying their fur When they eat they roll in water to remove food scrapes They forage in the morning and then rest mid day

Foraging They hunt in short dives, often to the sea floor Only marine mammal that can turn and lift over rocks to search for food Only marine mammal that catches fish with their forepaws rather than their teeth The sea otter has a loose pouch of skin across their chest that they store food in Also holds a rock in the ouch to use for cracking shells

Social structure Sea otters tend to rest together in single sex groups called rafts A raft usually contains between 10-100 otters They have a variety of vocal behaviors Females coo when they're content and males grunt Although they can be playful, they’re not considered social animals They spend a lot of time alone

Reproduction and lifestyle Autumn is the peak breeding season Sea otters are polygynous: males have multiple female partners Mating occurs in the water and it gets extremely rough Births usually occur in the water and its only one pup Nursing lasts up to 2-12 months

Sea otters highlight tape https://www.youtube.com/watch?v=cJTRCtwf_X0 https://www.youtube.com/watch?v=HXtMh2wlez0

Current event The Southern sea otter is in decline for the second year in a row. After being in a steady recovery for a decade. The numbers of sea otters have dropped mostly in the areas that they reproduce. "A number of human and natural factors may be influencing this trend, and we are working to better understand what those are," said Tinker, an adjunct professor of ecology and evolutionary biology at UC Santa Cruz and research scientist with the USGS Western Ecological Research Center. The southern sea otters are currently on the endangered list and the only way for them to be removed is if the number of otters stays at over 3,000 for three consecutive years. They say that the breeding age females are the ones that are dying. Since sea otters get their food from the shore they are being exposed to chemicals that are harming them. Tinker is currently studying other sea otters and how they react to different stressors and seeing why they’re healthier. He’s hoping to find an answer soon so he can save the southern sea otters. http://news.ucsc.edu/2010/08/3958.html

sources http://www.defenders.org/sea-otter/basic-facts http://www.marinemammalcenter.org/education/marine-mammal-information/sea-otter.html http://www.seaotter-sealion.org/seaotter/factsseaotter.html http://animals.nationalgeographic.com/animals/mammals/sea-otter/