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River Otter (Lutra canadensis)

Adaptable Aquatic Acrobats

Otters fall into the Mustelidae family tree, and are distant cousins of weasels, skunks and badgers. They can measure over two feet long, from whiskers to tail, and can weight over twenty five pounds. They look a little like a large weasel on land, and have been mistaken for a beaver in the water. The easiest way to identify them on land is by their large size; in the water, they roll, bob, and crane their necks more more than muskrats or beavers.

River Otters are well adapted to Minnesota's many lakes and rivers for many reasons, the first and most obvious being their ability to withstand Minnesota's extreme winters. Otters can survive even in the coldest of weather because of their oily fur and an extra layer of fat. Their pelts were prized by trappers and Native Americans alike because it is extremely resistant to cold temperatures.

Another reason Otters are so well adapted is their ability to eat nearly anything and everything in the water. Most of their diet consists of fish, mostly trout, bullheads, catfish and suckers, but they've also been known to eat frogs, mussels, snails, crayfish, and aquatic insects and insect larva. Some Otters have even been known to develop the hankering for ducklings, water snakes or muskrats!

It goes without saying that most of the Otter's hunting is done under the water. It's what they're made for! They have eyes that are specially adapted to see underwater, webbed feet, and nose flaps that fold over their nose. Like the seal, their bodies are sleek and streamlined, and like the cat, they are aided by an extremely sensitive set of whiskers, which they rely more than any other sense while diving in murky waters or under the ice.

The last thing that really makes the Otter an amazingly adaptable animal is the fact that it has so few predators. While some raptors may take an occasional Otter, and wolves and coyote (along with the domestic dog) may pick off any that travel overland, they're one of the largest semi-aquatic predators in Minnesota. They don't have to face off with Killer Whales or Polar Bears the way their Alaskan brethren do, or river-going constrictors the way their South American cousins do. Their relative size, coupled with amazing speed, intelligence, and agility make for an animal that is very difficult to beat in its native element. Despite this fact, they are not destructive animals. Their varied diet makes them much less likely to adversely affect any one species.

Otters have the reputation of being playful, and have been known to catch and release their prey (or when prey is not present, a pebble or empty seashell) in order to hone their hunting abilities. They will also wrestle with one another while on land or in the water, and will slide down snowy or muddy banks both as a mode of transportation and (apparently) for entertainment.

Some interesting River Otter facts:

• Otters often bash mollusk shells open on rocks, making them, along with raccoons, one of the few species in our state which can employ tools.
• Otters are extremely dedicated mothers. Mating begins in the spring, and gestation takes over a year in some cases. The young will stay with the mother for another year, learning to hunt and forage. Scientists believe that extended child-rearing is a prerequisite for intelligent species.
• The life span of a river otter can vary. They can reach up to 26 years of age in captivity, and about 14-15 years in the wild. This is influenced by the availability of food and habitat, the presence of other predators, disease, protection status, and water pollution.
• Otters are very picky about where they settle down. They like to have a lot of open land, often up to a mile to hunt and forage. They will move quite often, sometimes ranging up to fifty miles in a year (Audubon, Mammals).
• Many anglers assume that otters are detrimental to local fish populations. Scientists believe that the opposite is actually true.

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	National Audubon Society's Field Guide to Mammals
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	Tracking and the Art of Seeing

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