Last Updated on September 3, 2022 by Tommy
A sea otter, Enhydra lutris, is one of the most distinctive marine mammals living exclusively in cold coastal waters. These animals can weigh as much as 100 pounds while measuring up to 5 feet in length.
You might mistake them for corks or blobs bobbing along the water surface where kelp forests thrive. You’ll quickly realize, however, that you’re looking at the sea otter once you identify those adorable, whiskered furry faces!
We, here at Floofmania, understand that it’s easy to confuse sea otters for another animal, especially if they’re far from where you’re standing. So here’s a list of animals you might mistake for a sea otter’s fluffiness to help you out the next time you are unsure if you’ve spotted one or not:
The Sea Otters’ Fellow Otters
Table of Contents
- 1 The Sea Otters’ Fellow Otters
- 2 Sea Otters Share The Seas (And Shores) With Pinnipeds
- 3 The Sea Otters’ Fellow Mustelids
- 4 Other Mammals That Look Like Sea Otters
- 5 Author
There are currently 13 living carnivore members of the Lutrinae or the otter subfamily. It’s easy to mix up a sea otter for any of its cousins, so it’s only fair that we start with them.
All otters have relatively short limbs compared to their long, slender bodies. They also have webbing in their feet to help them swim, and together with their ability to hold their breaths underwater, they can forage for food, consisting of fish or invertebrates.
It can help to differentiate each member from one another by looking at their sizes, especially their tails. Knowing whether an otter is an aquatic (live primarily in freshwater and all types of water, in general), semiaquatic (spend part of their days on the water and the remaining on land), or a marine (saltwater exclusive habitats) individual is also beneficial.
North American River Otter
Also known as (A.K.A.): Northern River Otter; River Otter
This semiaquatic mammal lives in both freshwater and saltwater habitats. When people see the animal swim around in saltwater, they easily misidentify it as a sea otter that can spend almost all of its days in marine coastal waters. Here’s a video summarizing their differences:
- Sea otters are almost 4X bigger than river otters.
- River otters swim down on their bellies, with most of their bodies submerged in water, while sea otters like to float on their backs.
- A sea otter’s rudder-like tail is short and flat, while river otters have long pointed tails.
River otters are also more social than most mustelids and love to slide and play in their habitats. So you’ll often see them wrestling, chasing, and even grooming each other in their dens. On the other hand, sea otters can also socialize with their kind but they don’t live in dens as river otters do.
A.K.A.: Neotropical River Otter
Like its river otter cousins, the tail of a neotropical otter makes up most of its total length – more than half of its body length, in fact, which is a lot more than a sea otter’s tail.
Moreover, while a sea otter can only hold its breath underwater for less than 5 minutes, a neotropical otter can remain submerged in water for 8 minutes. They are excellent hunters that prefer to eat small fish that they expertly chase as they swim, with the help of their fully webbed feet.
Neotropical otters have a wide distribution of habitats because they are versatile and tolerant of environmental change. You can find them in Middle and South American wastewater treatment plants, crop plantations, ditches, and swamps.
A.K.A.: Giant River Otter
Experts have argued whether the largest otter species is the giant otter or the sea otter. Moreover, further studies confirmed that sea otters do, in fact, own the title because they can weigh as much as 100 pounds, while giant otters only weigh up to 75 pounds.
On the other hand, the giant otter takes the longest otter award because it can grow up to 6 feet in length, while most of its cousins can only measure 5 feet or less. They have also been gifted with loud, distinct vocalizations – making them the noisiest among otter species! (Even though sea otters can be quite vocal as well!)
Interestingly, the white to cream markings under its chin and throat are unique for every giant otter, much similar to the stripes on a zebra or to our fingerprints. Giant otters use their markings as “nametags” to identify themselves.
Before they can even approach a territory, they must perform a “periscoping” or routinely show off their marks to recognize family members and identify intruders.
A.K.A.: Marine Cat; Sea Cat
While many individuals refer to a sea otter as the smallest marine mammal, they may have forgotten that this rare marine otter exists.
Sea cats are highly elusive to humans to the point of living most of their lives between rocks and natural crevices just to hide. They don’t go too much into the ocean and rarely swim to freshwater bodies or estuaries of South America.
A.K.A.: European Otter; Eurasian River Otter; Common Otter; Old World Otter
These semiaquatic mammals are the most widely distributed otters throughout Asia, Europe, and North Africa. Their cute, brown-colored, furry faces resemble sea otters’ adorable whisker-filled muzzles. Most importantly, their presence in a habitat indicates that the ecosystem is healthy and thriving.
Congo Clawless Otter
A.K.A.: Cameroon Clawless Otter
The giant clawless otter of mid-Africa only has partial webbing on its feet but has sensitive forepaws like a sea otter which it also uses for foraging. Moreover, experts believe this otter species spends more time on land than other otters.
African Clawless Otter
A.K.A.: Cape Clawless Otter; Groot Otter
The Groot otter is the 2nd largest freshwater-living otter, next to the giant river otters. These big otters have partly webbed feet, which they use to help them catch frogs and invertebrates.
They must live near the water and always have their burrows nearby to be able to keep themselves cool in sub-Saharan Africa. They are also known to cool off by rubbing themselves on leaves and grass that may be a little damper or wetter than their environment.
Here is a summary of the mentioned otters’ lengths and weights to help you further identify them:
|Otter Type||Weight||Total Length||Tail Length|
|Sea Otter||100 pounds||5 feet||13 inches|
|North American River Otter||31 pounds||5 feet||20 inches|
|Neotropical Otter||33 pounds||5 feet||33 inches|
|Giant Otter||75 pounds||6 feet||28 inches|
|Marine Otter||11 pounds||3 feet||14 inches|
|Eurasian Otter||26 pounds||4.5 feet||18 inches|
|Congo Clawless Otter||60 pounds||5.6 feet||28 inches|
|African Clawless Otter||70 pounds||5.3 feet||20 inches|
Pinnipeds are large marine mammals that use blubber or a thick layer of fat to keep them warm. On the other hand, sea otters rely on their dense, air-trapping fur to maintain their body temperature and to keep them buoyant while swimming.
Sea otters only have their two hindlimbs acting as flippers when they swim. Meanwhile, this pinniped group’s marine mammals have all four limbs molded as flippers.
Because of their limbs, pinnipeds move with great ease in the water and relatively well on land where they rest, molt, and give birth.
On the contrary, sea otters can choose never to set foot on the ground unless necessary, such as when they need to stay away from turbulent waters for a short while during a storm.
A.K.A.: Earless seals; True seals
Seals are certainly bigger than sea otters. The elephant seal, in particular, can grow up to 20 feet and weigh as much as 6,000 pounds which is miles away from a sea otter’s 5 feet and 100 pounds!
Furthermore, if the two mammals were similar in size, it could be hard to distinguish them from one another. Although sea otters have external ears, they aren’t that noticeable sometimes, and their faces are comparable to seals that only have visible tiny ear slits or holes on their heads.
You will have to look at their tails to identify them correctly. In specific, a sea otter has a long, muscular tail while a seal only has a tiny nub of tail between its hind flippers – which actually looks like its tail, so be careful.
Nevertheless, seals use their small front flippers to “galumph” on land, while sea otters have small front limbs that they use to groom themselves.
A.K.A.: Eared seals
Sea lions are also larger than sea otters; the largest (Steller’s sea lion) can weigh up to 2,200 pounds and can be 10 feet in length.
Sea lions resemble sea otters as both have external ears or flaps. However, sea otters have regular, powerful front paws, while sea lions have large front flippers that they use together with their hind flippers to walk on land.
Walruses are larger than sea otters. They don’t have external ears like seals do and can use all of their limbs like sea lions to move terrestrially. Despite their size, their snouts full of whiskers can be compared to sea otters’ – as long as you don’t consider the two long tusks sticking out from their mouths.
Here’s a table to guide you in identifying sea otters from pinnipeds:
|Sea Otter||Mustelidae||100 pounds||5 feet|
|Seal||Phocidae||105 to 6,000 pounds||5 to 20 feet|
|Sea Lion||Otariidae||220 to 2,200 pounds||6 to 10 feet|
|Walrus||Odobenidae||1,800 to 4,400 pounds||7 to 12 feet|
The Sea Otters’ Fellow Mustelids
The Mustelidae, or the weasel family, comprises almost 60 extant species, making it the largest family in the Carnivora order or the meat-eating mammals.
Most mustelids are terrestrial (with one exception in the list), and some of them are:
|Tayra||15.4 pounds||3.8 feet|
|Mink||2 to 7 pounds||2.8 feet|
|Marten||4.4 pounds||1.9 feet|
|Badger||19 pounds||2.5 feet|
These small mammals, which are native to America, have short but strong claws suitable for running and climbing. Their small heads, black eyes, and long whiskers resemble a sea otter’s facial features.
Their resemblance is even more evident in white-furred tayras, which are not uncommon in the species compared to other mustelids.
Furthermore, tayras have patches of white fur on their throats that are unique to every individual and serve as their “nametags” for identification.
Minks are dark brown to black-colored, semiaquatic mammals – yes, they’re the exception on the listed terrestrial mustelids here!
Furthermore, minks are often confused with otters. The identifying feature would be how they swim: almost the entire back of a mink can be seen when swimming, unlike most otters who only stick their heads out in the water.
More importantly, both mink and sea otter moms can delay their pregnancies so that their babies can be born in time for optimal weather conditions, usually during spring, to ensure their survival.
These mothers can withhold implanting their fertilized egg cells or embryos for an average of 51 days (for minks) and 60 days (for sea otters) before their gestation periods begin.
Martens have large paws with partially retractable claws that they use to climb trees.
They live solitarily in forests full of pinecone trees and shrubs. Like sea otters, their furs are valuable, and they face threats from hunters and trappers because of this, even though hunting them is illegal in most places.
Badgers, like the pictured American badger, are solitary, nocturnal animals that rely on an omnivore diet of plants and meat to survive. They are recognizable for their huge foreclaws and distinct head markings. They generally resemble otters because of their short, stocky legs and muscular bodies.
Other Mammals That Look Like Sea Otters
The remaining animals on this list are primarily semiaquatic rodents, with one adorable-faced exception. Most of these mammals can be hard to distinguish from sea otters or otters, in general, when they’re already swimming or submerged in water.
Beavers are often mixed up with otters when swimming because they are quite large – they can weigh more than 50 pounds like many otter species!
Aside from this, the only slight difference when they swim is that beavers tend to stick both their heads and backs out of the water, so you’ll have to be extra observant on this. In addition, a beaver’s tail is flattened like a round paddle, while an otter’s tail flattens as it tapers off at the tail end.
Muskrats are medium-sized, semiaquatic North American rodents. They are a lot like sea otters when they swim:
- They can close off their ears.
- They have webbed hindfeet that serve as their main propellers.
- They have rudder-like tails that control the direction of where they’re going.
Moreover, their long tails are interestingly scaled rather than haired. These tails are even slightly vertically flattened, which is unique to their species.
Nutrias are large rodents smaller than beavers but larger than muskrats. You can identify one by looking for coarse fur and a hairless, rat-like tail. Its incisors are also orange in color and are easy to spot when it’s munching on food.
A Water Rat or Rakali is “the Australian otter” because many believe their ancestors originated from the continent. It resembles an otter with:
- Its elongated and streamlined body
- Its thick and muscular tail
- Its small, foldable ears
- Its blunt muzzle has dense, long whiskers
Additionally, a water rat’s fur is water-repellant and quick-drying.
Capybaras are native herbivores of South America. Like sea otters, they are semiaquatic mammals equipped with webbed feet for swimming.
Furthermore, capybaras are highly social species and are the world’s largest living rodent – they can even grow to the size of a Labrador Retriever!
Speaking of dogs…
A Border Terrier’s head and face are comparable to a sea otter’s because of their rounded features. Border terriers are only small dogs that can weigh up to 15 pounds. Nevertheless, their flat skulls and keen, alert eyes give them an uncanny resemblance to sea otters!
Despite their furry, cuddly face, The Border Terrier Club of America (BTCA) highly values the Border Terrier’s determined and fearless look. They even give out a yearly “Best Otter Head” trophy.
Hello! My name is Graciola Galo, but my friends call me “Gra” – so can you! Aside from being a dog lover, my bachelor’s degree in biology has helped me develop a deep appreciation for animals. I look forward to learning more about all kinds of wildlife in every future article I write for Floofmania and I aspire to impart that same awe and wonder to you, too!