Miscalibrated Internet Receptor Stalks

The holiday and pre-Star Wars season can be hectic. Take a breather. Read about otters!

The North American River Otter (Lontra canadensis) is distributed throughout Canada and the United States, but during the early period of European colonization in North America, it was extirpated from much of its historical range, particularly the interior United States. It is also called the common otter, river otter, or northern river otter. Although they can only live in areas near a permanent water source, they can easily adapt to life in rivers, lakes, streams, drainages, swamps and coastal areas.


The North American River Otter can grow up to 42 inches (107 cm) in body length, and weigh about 25 pounds (11.3 kg), with the average adult male outweighing the average adult female by around 5%. They have long, tapered bodies but are stocky in build, with short legs and thick necks. Their coats are usually a shade of brown, darker or lighter depending on the season and specific range. They have small rounded ears and long whiskers that allow it to sense prey when underwater. The right lungs of North American River Otters are larger than their left lungs, with the right lung having four lobes while the left has only two. This discrepancy is assumed to be an adaptation for a semi-aquatic life.

The diet of the North American River Otter depends upon its specific range, but mostly consists of fish, supplemented by amphibians, crustaceans, small mammals, and even turtles and birds. They are typically ambush hunters, and only rarely pursue prey as part of a long chase.


There are currently seven recognized subspecies:

  • Lontra canadensis canadensis
  • Lontra canadensis kodiacensis
  • Lontra canadensis lataxina
  • Lontra canadensis mira
  • Lontra canadensis pacifica
  • Lontra canadensis periclyzomae
  • Lontra canadensis sonora

North American River Otters are extremely social and spend their time among small family groups, which usually consist of an adult female and her offspring, as well as unrelated juvenile and adult “helpers”. Even unrelated males will form social groups, and share the same dens and latrines. Groups of otters engage in social grooming as well. The breeding season of the North American River Otter happens from mid-winter to early spring, and pregnant females start to look for birthing dens in the spring. But they’re usually looking for places to give birth to the litter they became pregnant with the year before - these otters are able to delay implantation of fertilized embryos until a more opportune time. Litter sizes range from one to five pups.


North American River Otters are known for their sense of play, which helps them to hone their hunting and survival skills. They communicate a lot of information through scent marking with urine, feces and secretions from their anal glands. They have a variety of vocalizations as well, chirping to each other over long distances and issuing alarm calls in the form of a loud snort. They are currently listed as a species of least concern by the IUCN, and reintroduction efforts have allowed them to repopulate some of the areas of their historical range from which they were extirpated long ago.

Source for all images used in this post.

Share This Story

Get our newsletter