Types of Otter

marine otter

We are lucky to share our world with 13 types of otter. Otters are a surprisingly diverse group of mammals – so much so you might not even suspect they are all related. Today we are going to learn some amazing facts about each of them, with cute pictures!

Some otters live in the ocean while others make their home in lakes, rivers and other freshwater or brackish environments. One otter might weigh in at 10 pounds while a distance relative tips the scales at a whopping 75 pounds. Some otter species are social butterflies and others are quite solitary. From foraging habits and food preferences to how they deliver and raise their young, each otter species is distinct from all the others.

Today, nearly all remaining otter species are considered vulnerable, threatened or endangered. This makes it all the more important that we learn as much as we can about otters so we can help them survive and thrive. So now let’s embark on an adventure to meet the 13 types of otter!

Fascinating Otter Facts

Otters have inhabited Earth for an estimated 30 million years. One of the largest otters lived more than six million years ago during the Miocene period. This otter reportedly weighed a whopping 110 pounds!

When learning about otters, one of the first things you will notice is they come with lots of new vocabulary words. For instance, a group of otters can be called a romp, a bevy, a lodge, a family or a raft. An otter’s home burrow is called a couch or a holt. A male otter is a boar and a female otter is a sow. A baby otter is called a pup.

Otters have earned special distinction in a few areas, most notably for their odiferous poop, called spraints. Depending on who you ask, spraints smell a lot like musty hay, freshly mown grass, jasmine flowers or rotted flesh. All otters are carnivorous. All belong to the order Mustelidae and the subfamily Lutrinae. The otter’s closest relations include badgers, mink, martens and wolverines.

Finally, there are two main categories of otter species: sea otters and river otters. There is only one type of sea otter. All the other otters are classified as river otters…even if they don’t live in rivers and even if they sometimes inhabit marine waters.

Types of Sea Otters

There are two characteristics that set sea otters apart from all other otters: their singular ocean-only habitat and their size. Sea otters are by far the largest of the modern otter species, weighing anywhere from 60 to 100 pounds.

Sea otters also have thicker, denser fur coats than their freshwater cousins. Rumor has it the typical sea otter coat contains more than one million individual hairs! Most importantly, it is sea otters we have to thank for the majority of those adorable photos and videos of otters swimming on their backs, holding hands and letting their pups ride around on their bellies.

Sea Otter (Enhydra lutris)

sea otter

The sea otter is the sole representative of its class. Sea otters cohabitate in single-gender communities called – adorably – rafts. While resting at sea, sea otters anchor themselves together using kelp like “rope” to keep the group members from drifting apart. The kelp also makes a great babysitter for the sea otter pups while the parent otters are out hunting.

Sea otters use their tummies as plates and employ tools like rocks to crack open tasty fresh shellfish to eat. Groups of sea otters have been reported living along the northeastern USA coastline as well as coastal Japan and parts of Russia and Canada.

Sadly sea otters today are truly an endangered species, having been hunted to the brink of extermination for their gorgeous thick and insulating pelts.

Types of River Otters

Calling non-sea otters “river otters” is something of a misnomer given that river otters can live in both freshwater and saltwater habitats. Yet river otters are distinct from sea otters in certain key ways. For example, the typical river otter is only one-third to one-half the size of their seagoing relatives, weighing in at just 10 to 30 pounds on average.

River otters are much more likely to split time between water and land. And river otters typically have larger litters than sea otters do. River otters also swim face-down like people do. So now let’s meet the 12 river otter species!

African Clawless Otter (Aonyx capensis)

african clawless otter

The African Clawless Otter inhabits large portions of central and southern Africa except in the Congo basin, which is also home to the Congo Clawless Otter. Preferred habitats include rivers, lakes, forests, grasslands and even deserts.

African Clawless Otters can grow more than five feet long and weigh as much as 48 pounds in adulthood. They like to eat crab and fish. These otters tend to be solitary except during mating season when they typically travel in pairs. Today, African Clawless Otters are listed as near threatened.

Asian Small-Clawed Otter (Aonyx cinereus)

asian otter

The Asian Small Clawed Otter is the smallest of the 13 otter species. They live in the southern parts of Asia, India and China as well as the Philippines and Indonesia. Unfortunately, these petite and sociable otters are now considered a vulnerable species due to habitat loss and fur poaching.

Congo Clawless Otter (Aonyx congicus)

The Congo Clawless Otter, or Swamp Otter, can grow up to five feet long and weigh as much as 40 pounds. Congo Clawless Otters actually start out life with claws but lose them in adulthood. In addition, they lack webbing on their front paws and have only limited webbing on their back paws.

Congo Clawless Otters live mainly in the Congo basin of western Africa as well as other outlying areas in Africa. Rivers, swamps (of course), streams and rainforests are favorite habitats. They are currently listed as near threatened.

Eurasian Otter (Lutra lutra)]

eurasian otter

The Eurasian Otter has a vast native habitat throughout Europe, Asia, parts of Russia and Africa, Ireland, Indonesia and Sri Lanka. They weigh between 15 and 19 pounds, putting them at the smaller end of the overall otter weight spectrum.

These otters are highly adaptable and eat a varied protein diet of both fish and smaller land mammals like rabbits. They are mostly solitary except during breeding season. Currently the Eurasian Otter is listed as near threatened.

Giant Otter (Pteronura brasiliensis)

giant otter

A Giant Otter can easily reach up to six feet from nose to tail tip. These otters live only in the South American Amazon basin. Unlike many other otter species, Giant Otters are outgoing and social, preferring to live in groups of 20 or more.

Because of the Giant Otter’s immense size, they can be fearsome hunters. While no self-respecting Giant Otter would turn down a fish meal, full grown adults have also been known to tackle piranhas, anacondas and even caiman on occasion! Unfortunately, these amazing animals are now listed as endangered.

Hairy Nosed Otter (Lutra sumatrana)

hairy nose otter

Even at first glance, it isn’t a stretch to figure out how the Hairy Nosed Otter got their name – where most otter species are bare-nosed, these otters have quite hairy snoots!

The Hairy Nosed Otter is deeply endangered and has dipped towards actual extinction several times over the last few decades. These are the rarest of all the otter species. Their preferred swamp forest home is hard to come by in their native southeast Asia. Hunting is a big contributor to their chronically declining numbers.

Marine Otter (Lontra felina)

marine otter

At first glance, the pacific South American Marine Otter may seem misplaced in being classified with the river otters group. However, Marine Otters spend time both in saltwater and freshwater areas. Most interestingly, the Marine Otter prefers to live on land and only head to the water when hungry.

Marine Otters are also intriguing because they are a scavenging species, meaning these otters have evolved to have some level of cohabitation with people. As you might expect, this hasn’t been advantageous for their numbers and Marine Otters are now classified as endangered.

Neotropical Otter (Lontra longicaudis)

Gorgeous Neotropical Otters live in Mexico, parts of Central and South America and the northern part of Argentina. Neotropical Otters are large in body and long in tail. Local fisherman have been known to tame and train these otters to help with fishing chores, earning them the nickname “water dog.” Once considered endangered, today this protected species is classified as near vulnerable.

North American River Otter (Lontra canadensis)

Sometimes called simply the Common Otter, the North American River Otter is one of only a handful of otter species that is continuing to hold their own, if not thrive outright, while living alongside humans.

The North American River Otter weighs in at between 10 and 30 pounds and, not surprisingly given their name, is found in most places throughout North America. These otters are popular fixtures at zoos, where they are admired for their playful and sociable antics.

Smooth Coated Otter (Lutrogale perspicillata)

The Smooth Coated Otter is found throughout much of India and southeast Asia as well as one isolated location in Iraq. These otters have a gorgeous brown and grey coat that has caused population problems due to hunting. Today, Smooth Coated Otters are classified as vulnerable by the IUCN.

Southern River Otter (Lontra provocax)

This Chile and Argentina native actually splits their time between freshwater and saltwater habitats. Other names include Chilean Otter and the charming Little Patagonian Wolf.

Sadly, the Southern River Otter is a rare sight today. This is mostly because these shy otters are having an increasingly difficult time finding secluded areas to call home.

Spotted Necked Otter (Hydrictis maculicollis; formerly Lutra maculicollis)

Sometimes also called the Speckle Throated Otter, the Spotted Necked Otter takes their species name from easy-to-see white patches along the underside of their lips, throat and body.

Spotted Necked Otters are one of the most playful otter species – both in groups and solo. They make their home throughout the central and southern areas in Africa. Currently, this species is classified as near threatened.

Which Types of Otter Are Your Favorite?

Otters are undeniably cute. Yet as you now know, most otter species are declining, some dangerously so. What is causing the steep worldwide decline of otter populations?

Outside of predation, pollution, hunting and habitat loss, would you believe publicity on social media is considered the primary threat? People see cute playful otter videos on social media and think otters make great pets. But this couldn’t be less accurate.

The truth is, the best way to enjoy the antics of adorable otters is to enjoy watching these animals in their natural wild homes. Which types of otter are your favorites? Let us know in the comments!

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  • Roberson, J. “How to Tell the Difference Between River Otters and Sea Otters,” Ocean Conservancy, 2021.
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