The return of the otter
By Robert A. Hedeen
By Robert A. Hedeen
The river or Canadian otter is a threatened species in Illinois and other states throughout the Midwest at this time. Knowing this, I was pleasantly surprised to see one of these interesting mammals swimming in the Kishwaukee River while canoeing with my son. The otter was sinuously swimming along with a flexibility of its pliant body that conjured up memories of The Indian Rubber Man I had seen as a boy in the side show of a circus.
When the otter, which is sometimes called fisher, water dog, or an appropriate Indian name noticed our presence, it quickly sounded. We were able to track the movements of this submerged, furry creature by observing exhaled air bubbles as they broke the surface. As the otter neared the bank, it suddenly surfaced with a small water snake in its mouth. After unceremoniously gulping down the unfortunate reptile, the aquatic hunter resubmerged, and the telltale trail of bubbles again led toward the bank. When the bubbles suddenly disappeared, we presumed the otter had entered its den, which frequently has the entrance under water, offering protection from possible enemies.
The river otter is one of the least known mammals of the United States. A member of the family Mustelidae, its cousins include weasels, wolverines, badgers, and martens. It ranges throughout Canada, Alaska. and the United States except in the Southwest. It is dark brown in color and about three and a half feet in length when mature. Having a dense pelage and a thick layer of fat beneath the skin, the otter does not hibernate and is active throughout the winter.
With a torpedo-shaped body, webbed feet, and a rudder-like tail, it is admirably adapted for swimming and diving. Its nostrils are slit-like and may be closed for prolonged submarine activity.
Though otters are widely distributed over America north of Mexico, their numbers have been declining for many years throughout its range. Pollution of waterways, trapping for fur, and uncalled-for killing by a few fishermen, who erroneously believe otters decimate fish populations, are probably some of the reasons for their decline in numbers.
That otters greatly reduce gamefish populations is a bum rap. Though it is true they enjoy a fish dinner now and then, the bulk of the otters diet is made up of crayfish, snakes, mussels, snails, and aquatic insects. In addition to animal food, vegetables in the form of pond and river weeds and algae, seem to be essential for their good health.
Emil Liers, a noted Minnesota naturalist, raised otters for years and studied them extensively. He found they were easily tamed and made delightful pets, even coming to him when he whistled. Liers observed that if fish made up more than 50 percent of their diet, they sickened and sometimes died.
Though otters are considered a threatened species in Illinois at this time, biologist Doug Dufford of the Illinois Department of Natural Resources believes their numbers have gradually increased over the last five or 10 years. This increase is due in part to the importation of otters from outside the state. About five years ago, Illinois made a deal with Kentucky to trade wild turkeys for otters. As Kentucky was also short of otters, it contracted with a private trapper in Louisiana to supply otters to be shipped to Illinois. Some 346 wild otters were trapped and relocated to Illinois.
As the Rock River watershed had many otter sightings, the Louisana animals were released in watersheds south of the Rock. The bordering states of Iowa and Missouri have also brought in otters from out of state to help their depleted populations rebuild themselves.
The antics of these animals are a delight to watch. The early American naturalists John James Audubon and Ernest Seton first described an unusual habit of this animalsliding down snow banks in winter and down slippery clay banks into the water in summer. These activities appear to be purely recreational in nature and of great amusement to the otters. When sliding, the otter lies on its belly with the forefeet bent backwards. Then the hind feet dig in and provide the impulse that sends the animal shooting down the incline while emitting sounds that seem to indicate extreme pleasure.
Come to think of it, if I may be anthropomorphic for a moment, I saw some members of the human species engaged in the same leisure activity shortly after the first snow fall this season.
The otter is a welcome member of our fauna, so lets hope its numbers continue to increase in the years to come. The Illinois DNR is to be commended for its efforts to help the otter in its struggle for survival in a sometimes hostile environment.
Dr. Robert Hedeen is a former resident of eastern Maryland, with degrees in zoology and botany. He is a former professor of biological science. He has had 30 scientific papers published, has written numerous magazine articles, and is the author of two books on marine biology of Maryland.