Happy Sea Otter Awareness Week!
Do you find it otterly confusing to distinguish between river otters and sea otters?
While we don’t have any sea otters here at the Edmonton Valley Zoo, we are home to four North American river otters named Steve, Bow, Missi, and Najoua.
To celebrate these adorable animals, we thought we otter make you aware of the differences between them.
Taxonomy
While there is only one species of sea otter (split into two regional subspecies), there are actually 12 different species of river otter found all over the world!
Size
Sea otters are much larger than river otters. An average sea otter weighs between 27-45 kg (60-100 lbs), while the more diminutive river otter weighs in between 4.5-13 kg (10-30 lbs).
Physicality
Size isn’t the only distinguishing feature between the two types of otters – they actually look quite different if you pay close attention.
Sea otters have shorter tails and hind feet that are paddle-like. They also have extremely dense fur. In fact, sea otters have the densest fur in the entire animal kingdom with up to one million hairs per square inch on their body!
By comparison, river otters have long tails and hind feet that are similar to their front ones. Their fur is less dense – they have short fur in two layers to keep them warm and to provide a waterproof layer.
Both types of otters need their coats to form a layer of insulation that traps air to keep them warm in chilly water.
Habitat
Sea otters are a true marine animal and are one of five types of marine mammals. They spend most of their time in salt water and are rarely found on land. They can dive to 90 m (300 feet), are comfortable floating on their backs for long periods of time, and even give birth in the water to one pup per pregnancy.
River otters are comfortable on land and in the water and are found in primarily freshwater habitats. However, they can also be found in estuaries and along the shores of the ocean. They tend not to venture out into the open ocean as they have to have land to sleep on, and are usually found in denser populations where food is plentiful. Tide pools offer lots of food so some of the largest congregations of otters are on the shorelines of Alaska.River Otters can often be found lounging on riverbanks. They dive to 18 m (60 feet) and will float on their backs briefly, but prefer to keep moving while swimming with most of their body submerged. They give birth to multiple pups in dens on land.
Stop by to visit our North American river otters the next time you are at the zoo. We promise you will be otterly entertained!