The North American river otter has overcome enormous odds to survive on earth for 25 million years.

Otters live throughout the United States and Canada. They thrive in some regions thanks to reintroduction programs that boosted numbers that had dwindled throughout the 20th century due to trapping for the fur trade, water pollution, increased recreational use of waterways and loss of habitat. The North American river otter is one of several New World species of river otters. Lincoln Park Zoo participates in the American Zoo and Aquarium Association’s Otter Species Survival Plan.

The otter is an extremely intelligent and curious animal that lives near rivers, lakes, streams and marshes.

They sometimes move into abandoned beaver lodges but more often build their dens under tree roots, rocks or logs.

Despite short legs, webbed feet and hunchbacked posture otters run up to 15 miles per hour on land, though they spend most of their time in or near water. Young otters take to the water naturally, but when learning to swim they will sometimes cling to their mother’s back, similar to a human toddler reluctant to take his first plunge. When swimming slowly underwater or at the surface, they use all four legs to dog paddle, leaving a V-shaped wake.

Underwater is where otters truly excel. Submerged, they move with sleek efficiency. Curious but secretive, otters are not as easily observed in the wild as other mammals. But you’ll have the opportunity to see these swimming machines in action at the Children’s Zoo. From inside the building, visitors can look through a window and see the otters on the surface and below the water.

The otter, slick and thickly furred, weighs anywhere from 10 to 30 pounds. Its body is streamlined in a nearly perfect hydrodynamic shape. Webbed feet, powerful hind legs and a muscular tail propel the animal through water like a mini-torpedo. The otter also has excellent underwater vision and long whiskers that detect turbulence created by prey. Nostrils located at the top of the otter’s nose allow the otter to breathe while most of its body is underwater. The nostrils automatically close upon submersion. In their exhibit pool, you may sometimes see the otters swimming in a circle to force fish up from the bottom, just as they do in lakes and streams. In the wild otters eat fish, crayfish, frogs and turtles.

Right about now you must be wondering about the otter’s reputation for being nature’s most fun-loving species. That’s not altogether accurate.

Otters are sometimes spotted “playing” in their natural habitats, that is, sliding down river banks and slipping like submarines below the surface. Think of kids splashing on a “Slip N’ Slide” on a summer’s day. They will run and slide and scream and bounce back up and do it all over again. There’s no scientific data to indicate otters slide down riverbanks just for fun. Their slippery slopes seem to serve as the most practical entry points to the river, not playgrounds.

Also, if an otter emits whistles or snorts or barks while taking the quickest, slickest route to the water, it may be doing so to establish its territory.