Biology Reference
In-Depth Information
Mink
(top)
; river otter
Otters are the closest thing to seals that freshwater provides. Propelled by wide webbed feet, the otter
is magnificently constructed for gliding easily through the water. Its fur is short and sleek, its body long
and cylindrical; even its long tail, thick at the base but tapering to a pointed tip, seems almost like an
extension of its streamlined body, rather than an appendage. Moreover, its eyes are well suited for un-
derwater vision, and it has the lung capacity to remain submerged for several minutes at a stretch.
Anyone fortunate enough to observe otters in the water for any length of time can readily see how at
ease they are there. With the utmost insouciance, they roll, dive, play, and generally disport themselves
with little apparent effort. Thus otters can accurately be termed “heavily aquatic.”
Otters feed primarily on a variety of aquatic prey, particularly fish. For that reason they are some-
times blamed for killing large numbers of trout and other valuable game fish. This is generally quite un-
just. Except for special circumstances (a small, stocked trout pond, for instance), otters, like any pred-
ator, will usually kill the easiest prey that requires the least expenditure of energy. That often means
so-called “rough fish”—suckers, dace, and the like—rather than swift, wary game fish.
Several years ago my older son and I were offered a rare treat—a graphic example of the otter's
liking for fish. We were canoeing down a broad, slow stretch of a stream appropriately named Otter
Creek. As we approached a huge elm tree that had fallen into the water, we suddenly saw movement
ahead of us. My son was in the bow, and he whispered, “Otters!”
Sure enough, there were two otters, rolling and diving around the skeleton of the old elm tree. We
quietly shipped our paddles and drifted nearer, when suddenly one of the otters, with a sizable fish in
its mouth, clambered up onto the trunk of the elm. There it proceeded to devour the fish at leisure, and
we were so close that we could even hear it crunch up the bones!
Anthropomorphism—attributing human thoughts and emotions to animals—is an easy trap to fall
into; animals aren't human and don't think and react as we do, however much we sometimes like to
think so. It's extremely difficult, however, to put any construction other than sheer playfulness on some
otter activities, notably sliding.
When otters climb steep banks and toboggan down a muddy, slippery slide into the water, time after
time, there appears to be no biological imperative behind it; it just seems to be a pleasurable activity.
Likewise, otters traveling in snow will fold their front legs back along their sides, push off with their
hind feet, and glide down the slightest slope wherever possible—and sometimes even push and slide on
a level. Whether sliding down a bank or gliding on the snow, the hind legs trail behind the body after
giving an initial push.
Because otters spend so much time in the water, and are mostly seen in or along the edges of it, most
people think they're almost completely tied to water. When the spirit moves them, however, otters can
be notable overland travelers, traversing several miles of dry land before reaching another body of wa-
ter. In the process, they are adept at finding small mammals and birds, insects, and similar terrestrial
food.
