River otters: a Colorado conservation comeback
summit daily news
SUMMIT COUNTY – Although they’re hard to spot, Colorado’s populations of river otters (Lontra canadensis) are alive, well and growing. The same couldn’t be said 40 years ago, when not a single otter swam through the state’s rivers in search of its daily meal of fish.
Human settlement, water pollution, stream diversions and trapping caused the species’ demise, causing them to disappear from Colorado altogether by the beginning of the 20th century.
But after a seven-decade absence, the Colorado Division of Wildlife reintroduced the critters back into several of the state’s rivers, including the Upper Colorado, the Gunnison, the Piedra and the Dolores. At the time of reintroduction, otters were placed on the state’s endangered species list. But as populations grew, free from the threat of trapping, their status changed to “threatened.” And today, the Division of Wildlife is in the process of conducting surveys to determine whether the species still even needs legal protection.
“At this point, otters are doing very well in Colorado,” wildlife biologist Michelle Cowardin said. “Up by the Grand-Summit county line, we’ve surveyed eight different reaches of streams, and in every one we see otter signs.”
Survey teams rarely get to look into the eyes of a river otter, but scat, dens and tracks provide ample evidence of their presence. Teams conduct their searches in the winter, when it’s easiest to find their tell-tale toboggan-like paths through the snow.
“They slide on their bellies to access water or when they’re traveling over a frozen river. They bound and slide, bound and slide – that’s how they move across the landscape,” Cowardin said.
River otters are able to withstand such icy environs thanks to an especially thick undercoat and water-repellent fur (which ironically caused its near extinction, since it was so coveted by 19th-century trappers). Also helpful are tiny ears and a small face, both of which keep much heat from escaping.
In winter and summer, the otter’s primary diet is fish, although they’ll also eat other kinds of prey like crayfish, birds or small mammals. Their favorite foraging areas are calm pools in rivers, which makes the herbivorous beaver among the otter’s best friends.
“Otters are strongly associated with beavers and beaver lodges. Otters don’t excavate their own dens, but when beavers dam an area, it creates deep pools where fish congregate. There’s definitely a relationship between beaver and otter,” Cowardin said.
Even under ice, otters will exploit pools in the river. They’re strong swimmers, using their sleek bodies, powerful tails and webbed feet to propel themselves through the water in an eel-like motion. They’re able to travel in air pockets under the ice, occasionally surfacing in open water or under ice heaves.
Although otters are indeed playful, Cowardin said that attribute is somewhat exaggerated in popular imagination.
“They’re mammals, and most mammals are playful, especially when they’re young. Otters are very intelligent and very curious, and with that combination, they will play,” she said.
But all the bounding and sliding that humans seem to find so endearing is just as much a form of transportation as it is play. Furthermore, adult females tend to appear much less playful, since they’re very alert and protective of their young.
Playful or not, otters are one of the most difficult wildlife species to observe in Summit County. Cowardin urges wildlife enthusiasts to report those rare sightings and to take pictures to aid in the agency’s monitoring efforts.
SDN reporter Julie Sutor can be reached at (970) 668-4630 or firstname.lastname@example.org.
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