Otters Dance Before Pooping, Plus More Fun Facts

Otters are carnivorous mammals in the Lutrinae branch of the diverse Mustelidae family, which includes weasels, badgers, stoats, wolverines, and ferrets, among others. There are 13 living otter species inhabiting aquatic habitats all over the world, with the exceptions of Australia and Antarctica. Almost everyone knows that otters are at home in the water, but did you know they have specialized vision to help them see underwater? Or that baby sea otters can’t sink? That’s just the beginning. Read on to discover more otterly amazing facts about otters.

1. Otters Are Very Chatty

Many otter species are social and use a variety of vocalizations to communicate with one another. Two of the most social species, giant river otters (Pteronura brasiliensis) and Asian small-clawed otters (Aonyx cinerea), are also the most vocal. Giant river otters have at least 22 distinct calls in their repertoire, including hums, growls, screams, whistles, and barks. They even say “hah!” as a warning or to indicate submission. Asian small-clawed otters have more than 12 documented calls, such as chirps, squeaks, growls, screams, and barks. Otter groups use these calls loudly and often to reinforce their social bonds.

2. Otters Have Adaptations for Underwater Vision

All otters are semi-aquatic, except for sea otters (Enhydra lutris) and marine otters (Lontra felina), which are almost entirely aquatic. Otters have ocular adaptations that allow them to see above and below the surface of the water. Both saltwater and freshwater otters can contract their iris muscles, causing the surface of the frontal lens to bend. This allows them to compensate for the refraction of light as they transition from air to water. Research has shown that these adaptations allow otters to have near-equivalent visual acuity underwater and in air.

3. These Whiskers Are Made for Hunting

Otters have whiskers on their muzzles, called vibrissae. They may also have superciliary (“eyebrow”) whiskers and neck whiskers. The nerve endings at the base of the whiskers send sensory information to the otter’s brain, providing the otter with information about its surroundings. These stiff hairs are sensitive to vibrations and movement, which help otters hunt prey when underwater visibility is poor. Their whiskers also assist them with navigation and spatial awareness. This helps them avoid obstacles and maintain their sense of direction in turbulent water.

4. Otters Can Discriminate Between Colors

Research indicates otters have dichromatic vision. One type of cone is sensitive to green-to-red wavelengths, and the other is sensitive to blue-to-ultraviolet wavelengths. This is similar to the color vision of humans who are red-green colorblind. Otters also have the ability to discriminate between colors. Asian small-clawed otters were shown to discriminate gray from white, blue, green, and red. They could also distinguish between blue and green, as well as blue and red. North American river otters (Lontra canadensis) were documented to differentiate between yellow and red, as well as blue and red. European river otters (Lutra lutra) were observed to discriminate blue and green from different shades of gray.

5. Some Otter Species Have an Enhanced Sense of Touch

Most otter species forage with their mouths. However, both sea otters and Asian small-clawed otters use their forepaws to locate prey. In sea otters, their hairless palms and digits are fused, resembling a hand inside a mitten. Asian small-clawed otters have less webbing between the digits of their fleshy forepaws, which gives them greater dexterity. In both species, the skin on their paws is very sensitive. Researchers have found that the area of the brain that interprets signals from the paws of these two otter species is disproportionately large compared with other otter species.

6. Otters Are Literally Party Poopers

Many otter species, including, but not limited to giant river otters, North American river otters, African clawless otters (Aonyx capensis), smooth-coated otters (Lutrogale perspicillata), Asian small-clawed otters, and Eurasian river otters, use communal latrines. These latrines are typically established in areas that allow easy access to water. Otter latrines are not just public toilets; they are social hubs where otters leave feces (called spraints) and use their scent glands to mark the area and exchange information. Spraints can communicate an otter’s identity, social position, and reproductive status. They can also communicate information about resources and territorial boundaries.

7. They Do a Little Dance Before They Go to the Bathroom

Speaking of otter spraint, otters do a little dance before they use the latrine. They stomp in place with their hind feet, lift their tails in the air, and wave their bottoms. Researchers are not certain why they dance, but one theory is that it helps spread the scent of the droppings. Since other otters often join in, researchers believe it could also be a type of signaling behavior. This dancing has been observed at crossover latrines, centralized locations where trails or bodies of water meet. Larger groups come together at these crossover latrines, but researchers have found more signaling behavior than social behavior. These gatherings may help otters assess others and decide which group to join.

8. The Rarest Otter Species Was Thought to Be Extinct

The rarest otter species, the hairy-nosed otter (Lutra sumatrana), was believed to be extinct in 1998 after there had been no sightings for a decade. However, camera traps have since provided evidence that the otter still lives in the wild in parts of Southeast Asia. Hairy-nosed otters have also been found living as pets in Thailand. One otter named Oreo was recently surrendered to a wildlife sanctuary in Thailand after living as a pet for six years. This species is so rare that Oreo is believed to be one of only two hairy-nosed otters living in sanctuaries around the world.

9. Newborn Sea Otter Pups Can’t Sink

Sea otters don’t have blubber, but they compensate by having the thickest fur in the world. Adult sea otters can have up to one million hair follicles per square inch of fur. When otters groom their fur, they blow air into their undercoats, forming air pockets that provide more insulation. When the mother sea otter grooms her pup, she also blows air into the pup’s coat. Although baby sea otter fur is still growing, their smaller body mass means their fur provides greater buoyant force. Their fur becomes so aerated that they cannot sink or dive. The pup bobs in the water like a cork, so the mother wraps it in seaweed to ensure it doesn’t drift away while she forages for food.

10. Otters Can Be as Small as Cats or as Large as Humans

Otter species run the gamut when it comes to size. The smallest otter species is the Asian small-clawed otter, which only grows up to 3 feet long, including the tail. They weigh up to about 10 pounds, which is roughly the size of the average house cat. The largest species is the giant river otter, which can grow to nearly 6 feet in length and weigh upwards of 75 pounds. Giant river otters are longer than the average U.S. male height of 5 feet 9 inches and weigh slightly more than the average 10-year-old boy in the U.S. Sea otters’ maximum length is a foot shorter than giant otters, but they can weigh up to 100 pounds.

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