Zoo river otters get swim lessons from mom

April 21, 2017 - 1:24pm

Learning to swim isn’t easy, even for river otters.

Nellie and Tucker, a pair of North American river otters born at the Oregon Zoo in late February, have begun taking their first dips, but not without a lot of help from their mom, Tilly.

“Many people don’t realize that river otters need to learn how to swim just like us,” said keeper Celess Edinger. “Tilly’s a great swim instructor.”

According to Edinger, Tilly begins each lesson by carrying her pup to the water’s edge and then plunging in, just as otter moms do in the wild. Baby otters are extremely buoyant, so Nellie and Tucker have built-in water wings for their swim lessons.

“It might look a bit rough to a casual observer,” Edinger said. “Tilly grabs them by the scruff of their necks and dunks them in the water. But that’s natural river otter behavior. It’s how they learn to swim.” 

Until last week, Tilly and her babies had occupied a private, off-exhibit maternity den. River otters are very dependent on their mothers when they’re born. It’s usually three to five weeks before young otters open their eyes, and about five weeks before they first walk.

Last week, she moved her pups to a den that connects with the outdoor habitat, and since then the otters have been making quite a splash. The best time for zoo visitors to catch them is between 9:30 a.m. and noon, though the otters don’t always decide to venture out, Edinger said.

The female pup — Nehalem, or Nellie for short — was named after the river that flows nearly 120 miles from the Coast Range down to Nehalem Bay. The male pup is Nestucca, Tucker for short, after a forested river near the coast, known for its steelhead and salmon.

“For river otters, we like to choose names based on local waterways,” said Julie Christie, senior keeper for the zoo’s North America section. “River otters are sensitive to water pollution, but we’re fortunate to live in a region that supports a healthy otter population. We want these pups’ names to highlight the importance of protecting our rivers, streams and wetlands.”

Tilly, named after the Tillamook River, was found orphaned near Johnson Creek in 2009. She was about 4 months old, had been wounded by an animal attack and was seriously malnourished. Once her health had stabilized, Tilly came to the Oregon Zoo in a transfer facilitated by the Oregon Department of Fish and Wildlife, which oversees the species’ protection.

“She was a tough little otter,” remembered curator Amy Cutting, who oversees the zoo’s North America section. “She was small and alone when she was found, so it’s great to see her doing well now and raising pups of her own. She’s been a terrific mom.”      

The pup’s father, B.C. (short for Buttercup), also had a rough start to life. Orphaned near Star City, Ark., in 2009, he was initially taken in by the Little Rock Zoo. He was transferred to the Oregon Zoo the following year, and he and Tilly have been playful visitor favorites ever since. Because both adult otters were born in the wild, they are considered genetically important for the breeding otter population in North American zoos.

Once threatened by fur trappers, North American river otters are now considered rare throughout most of the U.S. due to habitat destruction and water pollution. They are relatively abundant in healthy river systems of the Pacific Northwest though, and are frequently observed in local waterways.

Metro, the regional government that manages the Oregon Zoo, has preserved and restored more than 90 miles of river and stream banks through its voter-supported natural area programs. By protecting water quality and habitat, these programs aim to provide the healthy ecosystems needed for otters, fish and other wildlife to thrive.