Meet Your Neighbors

River Otters:
Belly Sled Included

Children aren’t the only Chicago-area creatures eagerly awaiting the first snow with sledding on their minds. Although they don’t require wooden sleds, playful river otters, Lontra canadensis, often romp through snowy woods, coasting down riverbanks and across ice on their bellies.

But a river otter’s body, as its name suggests, is made more with swimming in mind than sledding. It shoots sleekly through the water, its muscular body propelled forcefully by a thick tail and webbed feet. On land, otters lack the grace they display in the water. They bound forward, accordion-style, a few times before sliding several feet. Thanks to this odd style of locomotion, otter tracks can resemble Morse code (click here and scroll down for picture).

Regional otters prefer to live in woodland lakes, rivers, and their associated wetlands. They frequently occupy abandoned beaver dens to rest or raise their young. Their apparent “friendliness” and habit of approaching people may be due to their near-sightedness, which reportedly improves their ability to see underwater. As a top predator feeding on fish, they play an important role in the river’s food chain.

Although river otters were common in Chicago Wilderness prior to European settlement, a combination of overhunting, habitat loss, and pollution over the decades landed them on the Illinois state endangered list by 1989, when there were thought to be fewer than 100 otters statewide.

A 1990s recovery plan created by the Illinois Department of Natural Resources set out on a quest for suitable habitat and water quality. Researchers found that environmental conditions had actually improved in some areas, so they released more than 300 Louisiana otters into the Illinois wetlands, in hopes of rebuilding the once-strong otter population. The effort has achieved some promising results — after an upgrade to threatened status in 1999, the river otter was lifted from the state list entirely in February 2004.

Although otter populations statewide have grown, Chicago Wilderness otters are still rare. “From 1994 to 2004, we had 12 reliable sightings of river otters in the Des Plaines River and Lake Michigan Tributaries Population Management Unit, 18 in the Fox River System PMU, and five in the Kankakee-Iroquois River System PMU,” says Bob Bluett, a biologist with the Illinois Department of Natural Resources.

Because otters prefer to live in areas where there is clean water and suitable habitat, they are good indicators of wetland conditions. Their presence anywhere, says Bluett, is a sign of improving water quality and fish populations, better-regulated fur harvests, and various habitat improvements.

According to Bluett, threats to otter habitat vary across the state. In northeastern Illinois, loss and degradation of wetlands due to invasive plants, siltation, and fragmentation by development could cause long-term problems. In addition, underground drainage systems and impervious surfaces such as parking lots cause large fluctuations in river levels, which can disturb otter feeding and breeding. But as humans begin to act more on the realization that clean rivers bordered by healthy wetlands can provide us with benefits such as flood control, water-based recreation, and cleaner drinking water, we’re bound to experience many other, wilder, benefits — some in the form of this sleek, furry sledder.

— Sarah Forte

Related Articles:

“Otter Limits” in Natural Events, CW Winter 2000