Sea otters (Enhydra lutris) are aquatic carnivores that reside in coastal areas of the Pacific Ocean, including waters by the United States, Japan, Canada, Russia and Mexico. These smallish creatures once had a rather sizable population throughout their home bases. Sea otters usually live for a maximum of 23 years.
In the past, sea otters were believed to be numerous, with populations thought to be between 150,000 and 300,000 specimens. Presently, they're considered to be an endangered group of animals, as indicated by the 2011 IUCN Red List of Threatened Species' report. This categorization is a result of extensive drops in population over a lengthy period of time. Between 2004 and 2007, the global population of sea otters was guessed to be nearly 107,000. A low in the species' population occurred in 1911, when there were believed to be fewer than 2,000 of them. In the modern day, sea otters have legal protections. Many conservation efforts are also in place, including those that involve breeding the animals in captivity and bringing them back into their natural habitats at later times.
One factor that in the past brought upon the endangered status of the species is hunting by human beings -- for purposes of acquiring their pelts. Although the International Fur Seal Treaty of 1911 made pelagic hunting of seals illicit, numbers of the species had already taken a massive hit -- extremely close to extinction.
Oil spills are a major concern for sea otters as a species. Direct contact with oil can lead to hypothermia in sea otters, as it triggers their coats to lose insulation abilities. It can also bring upon pneumonia. When combined with the animals' lack of blubber, that absence of insulation is a serious risk to their well-being. Apart from insulation issues, oil also is a hazard because the otters can accidentally take it in while cleaning themselves. Consumption of oil can wreak havoc on their lungs and digestive systems, and even lead to fatalities.
Infection is also a major dilemma for the continued survival of sea otters. A specific infectious ailment that regularly affects sea otters is called "Toxoplasma gondii," a parasite prevalent in domestic felines. Sea otters are believed to contract the parasite via exposure to cat stools -- a possible result of pet owners flushing their cat litter and getting their animals' fecal matter into the sewage system.
Commercial fishing is also a major risk to sea otters, as specimens frequently get trapped -- and deeply snarled -- inside nets. This trapping ultimately leads to their deaths by drowning. Gill nets are specifically troubling for sea otters.
Other prominent risks to sea otters include being hit by boats, the presence of killer whales -- a frequent predator -- and ruination of their coastal environments because of timber harvesting.