Tilly, a North American River Otter, is raising two tiny pups, born February 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.
Keepers have yet to decide on a name for the two new pups, though it is likely they will be named after Oregon rivers or waterways like their older siblings.
"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."
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.