23 Interesting Otter Facts

By Karin Lehnardt, Senior Writer

Published August 31, 2024

Southern sea otters are the smallest marine mammal in North America, but they are the largest of all the members of the Mustelidae family (which includes skunks and wolverines)._[2]
There are 13 otter species, including giant otters, African clawless otters, North American river otters, and neotropical otters._[2]
Sea otters have the thickest fur of any animal in the world, at 1 million hairs per square inch._[2]
The fur trade in the 18th and 19th centuries drove sea otters to near extinction by the early 1900s. In 1911, the International Fur Seal Treaty banned the hunting of sea otters, but they were already almost gone._[2]
The word "otter" is from the root "*wodr," which also gave rise to the word "water."_[7]

The word "otter" is related to the word "water"

Sea otters must eat 25% of their body weight in food every day. This means they spend nearly 50% of their day looking for food._[2]
Only one species of otter is fully aquatic: the sea otter, or Enhydra lutris. Not all otters are sea otters._[11]
Otters often have a favorite rock that they may keep their entire lives by holding it in a skin pocket under one arm._[9]
Otters live on every continent except Antarctica._[2]

The cutest handshake (Photo Credit: RocketNews2)

Visitors to a zoo in Japan have the chance to shake hands with otters. Asian small-clawed otters, the smallest of the otter species, can reach their hand through a small opening to take food from and grab the fingers of visitors._[12]
All otters belong to the Mustelidae family, which is one of the oldest carnivorous mammal families on Earth. They evolved over 40 million years ago. Most have short legs, thick fur, and long bodies. Otter relatives include badgers, wolverines, and weasels._[8]
Giant river otters can swim as fast as 8.7 mph (14 km/h), which is nearly twice as fast as Olympic swimmer Michael Phelps._[5]
Sea otters can hold their breath for about five minutes. River otters can hold their breath for up to 8 minutes._[10]
An estimated 90% of sea otters live around coastal Alaska. They can be found in Kodiak National Wildlife Refuge, Kenai Fjords National Park, and Glacier Bay National Park. South sea otters live along the mainland coastline of California, from San Mateo County to Santa Barbara County._[6]
The hairy-nosed otter is the rarest otter. It's known as a Lazarus species because it was thought to be extinct until 1998, when a scientist in Thailand found small groups of them._[3]
Otter poo is called "spraint," and it smells like freshly mown hay._[4]

Otter spraint is known for its distinct smell, which ranges from smelling like fresh cut hay to putrified fish

Baby sea otters are often born in the winter, unable to swim. A mother otter will carry her young pup on her belly while they rest, and she wraps the pup in kelp to keep it from floating away when she leaves to find food._[1]
Unlike other marine animals, sea otters don't have insulating blubber. This means they need to eat 25%–35% of their body weight each day to maintain body temperature._[9]
A group of otters is called a romp._[8]
Out of the 13 species of otters, the United States is home to two: the North American river otter and the sea otter. While sea otters weigh around 45–90 pounds, river otters are smaller and weigh between 10–30 pounds._[6]

Sea otters are considered a keystone species in their ecosystem

While other otters rebounded after the 1911 hunting ban, sea otter population growth has slowed in recent years due to pollution and environmental pathogens. There are only about 3,000 left in the wild today._[2]
Freshwater otters usually sleep above ground or in dens. Sea otters sleep floating on their backs at sea._[5]
In the United States, it is illegal to touch or catch a sea otter._[2]