Cool critters: River otters – long may they slide

River otters really do have more fun. They jostle, belly-slide across ice and snow and toboggan down embankments into water. Splish splash.

Few mammals are known to frolic as much as otters do, said Mark Vekasy, district wildlife biologist with the Washington Department of Fish and Wildlife.

“Beavers are always busy, but not the river otter,” he said. “Even the adults seem to have plenty of free time on their hands to engage in activities that appear to be play.”

The American river otter, scientifically known as Lontra canadensis, is fairly common in the Inland Northwest and throughout Washington state, Vekasy explained. And despite the “river” part of its common name, it also lives in streams, ponds, lakes and wetlands, he added.

And this time of year, the region is the otter’s winter playground. While many critters slow down during the season, river otters are energetic and mobile – belly sliding across wintry landscapes, torpedoing down streambanks and somersaulting in frigid waters. They’ve even been documented tossing rocks and chunks of ice into the air. Showoffs.

No wonder a group of otters is called a romp.

Otters are a member of the Mustelidae family, a large clan of carnivorous mammals that includes weasels, badgers, minks and wolverines. Two otter species call North America home: the river otter, which averages 20-30 pounds, and the much heftier sea otter that weighs 60-90 pounds. Where sea otters spend most of their lives in water, river otters spend about two-thirds of the time on land near waterways, according to the Seattle Aquarium.

And guess what? Unless you’re a night owl, you’re more likely to see river otters this time of year than in summer, researchers have found.

“During winter, otters are more active in daytime. In warm months, they are most active between dusk and dawn,” scientists concluded in a 1994 study published in the Canadian Journal of Zoology.

So, not only do river otters thrive in winter, “they actually seem to enjoy it,” said Vekasy of the WDFW.

How do they do it?

First, otters are covered in a thick, dense coat that even wool and Gor-Tex wearers would envy. Picture a velvety brown garment topped with waterproof guard hairs. And in a lower layer, wavy hairs create air bubbles that help prevent cold water from reaching the animal’s skin.

Otters also have an inner furnace – a supercharged metabolic rate that generates body heat and fuels their energy needs, researchers have found.

For them to support their keyed-up metabolisms, they gorge on food such as fish, crayfish, turtles and frogs. In fact, they consume up about 20% of their body weight each day. Then, through a unique metabolic short circuit, energy stored in their muscles generates heat even when they’re napping, according to scientific studies.

Otters run hot, which enables them to play. But they’re also seriously cute, with tubular brown bodies, doe eyes, button noses framed with whiskers and webbed feet. They even chirp and chuckle at each another.

Should you spot river otters in the wild, observe quietly and don’t get too close, Vekasy advised. Though rare, otters have been known to bite humans when stressed or threatened, he said.

Besides being cute and fun to watch, the presence of river otters is a wildlife conservation success story. Fifty years ago, unregulated trapping, water pollution and habitat destruction had led to a steep decline in populations in large portions of their range.

After four decades of recovering, the river otter is “once again found in every continental state,” according to the National Wildlife Federation.

And, you might say, they’re making a big splash.