Otter | San Diego Zoo Animals & Plants

It’s hard to determine the otter population in native habitats, because of their secretive nature and wide range. There are many studies showing the decline or extinction of otters in certain areas. In most countries, otters are now classified as either threatened or endangered and are under special protection. The North American river otter Lontra canadensis was once in serious trouble because of habitat destruction and trapping, but as a result of reintroduction projects and legal protection, their numbers have increased throughout North America.

There are several factors affecting the decline of river otters. The pollution of rivers and waterways is a major threat. Substances such as organic waste from domestic and industrial sources and pesticides used to control insects are often washed into waterways. Oil spills contaminate an otter’s fur, increasing heat loss, reducing buoyancy, and proving toxic when ingested.

Habitat destruction or loss is also a major factor affecting the river otter. Construction of dams leaves lower rivers dry and unsuitable for river otter populations. Deforestation affects river otters through much of South America and Asia. Mining rivers for gravel kills the fish that are the otters’ main food source. Changing river courses for flood prevention and agriculture destroys otter habitat. River otters are also hunted and trapped for their pelts or killed by fishermen who see them as competition. And otters often get trapped and drown in fishing nets.

California or southern sea otters Enhydra lutris nereis were nearly wiped out a century ago, hunted for their thick fur. An international treaty banned otter hunting in 1911, but the California sea otters have been slow to recover from the devastation. Pollutants in the water off California’s coast and the increase of commercial fishing operations may have negatively affected this population.

Today, giant otters Pteronura brasiliensis, marine otters Lontra felina, South American river otters Lontra provocax, sea otters Enhydra lutris, and hairy-nosed otters Lutra sumatrana are endangered.

Want to help otters? Use water-efficient appliances! Water-efficient washing machines and dishwashers, low-flow showerheads, and low-flush toilets can reduce water consumption by 60 to 90 percent. That means more clean water stays in our rivers where river otters live.

By supporting San Diego Zoo Wildlife Alliance, you are our ally in saving and protecting wildlife worldwide.