Otter babies: River otter Tilly is raising 2 new pups

March 6, 2017 - 12:57pm

Keepers say Tilly and pups are doing well in their behind-the-scenes maternity den

Tilly, a North American river otter, is raising two tiny pups, born Feb. 26 at the Oregon Zoo. The new arrivals — one male and one female — weighed around 4 ounces each at birth and have already doubled that thanks to their mother's naturally high-fat milk.

"Young river otters are extremely dependent on their moms, and Tilly has been very nurturing," said Julie Christie, senior keeper for the zoo's North America area. "She did a great job raising her first two pups, Mo and Ziggy, both born in 2013. And she was a terrific adoptive mom to Little Pudding, the orphan pup who was rescued from a roadside in 2015. We expect she'll do well with her new babies as well."

Tilly and her pups are currently in a private maternity den, and it will likely be another month or two before visitors can see them in their Cascade Stream and Pond habitat. Young river otters usually open their eyes after three to six weeks, and begin walking at about five weeks.

Surprisingly, swimming does not come naturally to river otters — pups must be taught to swim by their moms. Tilly's first pup, Mo, made a big splash with otter fans a few years ago when a video of his rough-and-tumble swim lessons went viral, logging more than 890,000 views on the zoo's YouTube channel.

Keepers have yet to decide on a name for the two new pups, though it is likely they will be named after local rivers or waterways. Mo was named for the Molalla River, and Ziggy for the ZigZag. Little Pudding bears the name of a Pudding River tributary that joins the main stem in Marion County.

"This will be the first time Tilly has raised more than one pup at a time," said curator Amy Cutting, who oversees the zoo's North America and marine life areas. "It's exciting that they'll be growing up together and have the opportunity to play and wrestle with each other. Tilly's always been an extremely attentive mother, so it will be interesting to see what happens when her pups go in two different directions."

A third pup, much smaller and weaker than the other two, was also part of the Feb. litter, but did not survive, Cutting said.

Since both Tilly and the pup's father, B.C., were born in the wild, they are considered genetically important for the breeding otter population in North American zoos. Both parents are rescue animals who had a rough start to life.

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 and marine life areas. "She was in really bad shape 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), was found orphaned near Star City, Ark., also in 2009. He was initially taken in by the Little Rock Zoo, but transferred here the following year as a companion for Tilly. The two otters hit it off quickly and have been playful visitor favorites ever since.

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.