For the first time, Shedd Aquarium will train sea otters to serve as surrogate moms to orphaned pups

Otter 926 perched on a ledge in her new room at Shedd Aquarium, as close as she could get to the newspaper photographer on the other side of a built-in window.

From there, she demonstrated her impressive grooming skills, pausing occasionally to look up at the photographer, as if ready for her close-up.

Not to be outdone, a second southern sea otter frolicked in the duo’s private pool, somersaulting four times in a row, flipping over on her back to do side rolls, and finally submerging so only her triangular tail could be seen, wagging triumphantly in the air.

Sea otters can get by on looks and charm alone, but the two latest arrivals at Shedd Aquarium are marine mammals with a mission.

Otters 926 and 929 are two recruits in a pioneering California program in which young females are trained to act as surrogate mothers to orphaned pups, imparting the skills that allow the youngsters to be released into the wild.

“This is a step in a new direction and we’re all really excited about it,” said Megan Vens-Policky, Shedd senior animal care specialist. “Our mission here at Shedd is to spark compassion, curiosity and conservation, and this project really allows us to do all three of those things.”

The two otters, who have not received permanent names, arrived Wednesday from Aquarium of the Pacific, a partner institution in Monterey Bay Aquarium’s pioneering otter surrogacy program. Shedd staff will help the females hone skills such as diving, foraging and carrying pups.

Then, the two otters will return to California — home of the southern sea otter — to be matched with motherless youngsters.

Once numbering roughly 150,000 to 300,000 worldwide, sea otters were hunted nearly to extinction in the 1700s and 1800s. By the early 1900s, fewer than 2,000 remained worldwide, according to the U.S. Fish and Wildlife Service.

Numbers have grown since then, but the southern sea otter remains a federally threatened species, with only about 3,000 left in a small portion of the animal’s historic range.

“They face a lot of constraints that other endangered and threatened populations do,” said Vens-Policky. “They have to worry about oil spills, competition for food, pollution, (and) climate change.”

In a 2019 study in Oryx — The International Journal of Conservation, the otter surrogate mom program reported on the release of 37 of its surrogate-raised orphans. Survival and reproductive rates were similar to those of wild otters, according to the study, and the surrogate-raised otters and their descendants contributed substantially to population growth in the area where they were released.

Sea otter moms care for their pups, teaching them vital survival skills, so when a pup is orphaned, it’s a challenge to prepare him or her for a return to the wild.

That’s where the Otters 926 and 929 come in. Rescued orphans who received some surrogate mothering but were not suitable for release into the wild, the duo will hone their otter skills at the Shedd, Vens-Policky said.

Staff will encourage the surrogate moms, both about 9 months old and about 30 pounds, to practice diving and foraging. A lot of their feeding will involve staff scattering and hiding food in their exhibit so the otters can practice searching for it.

Staff will also teach the otters (currently housed behind the scenes) to retrieve objects, which should eventually translate to retrieving and carrying a young pup.

“We use positive reinforcement training, so if we see an animal doing something we like, we let them know to keep doing that,” said Vens-Policky. “We can do that in a number of different ways, so we might give the otters a toy item or an enrichment item and ask them to give it back to us.”

If an otter can return an item, she will move on to retrieving it from a greater distance. Teaching happens in baby steps that build up to bigger goals, Vens-Policky said.

“Otters are very well-equipped for learning,” she noted. “Because they are so curious, that really lends itself to being a good learner. They will try new things. They explore. As they get more comfortable, we’ll start to see more of that, and that’s what will ultimately lead to the kind of training that we’re talking about.”

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Otter pups have to learn to groom themselves — a skill that helps keep them warm — and mother otters are the ideal instructors, although humans can step in when there’s no alternative. Pups learn grooming skills by watching their mothers, and by being groomed by them.

The surrogate moms who arrived this week know how to get the job done — thanks in part to some limited surrogate parenting they themselves received — and they can pass that knowledge on to pups.

“Otters have very dexterous paws, and they have additional vertebrae in their backs so they’re really bendy. They use those paws to comb through the fur, and then because they’re so flexible they can really twist and turn and reach every part of their body,” Vens-Policky said.

Otters also blow air bubbles into their lower layer of fur, which is very soft. The air gives the otters — who have a dense outer coat but no protective blubber layer — an additional layer of insulation against the cold.

When the Chicago-trained surrogate moms are ready, they will be flown back to California, where they will each be assigned to a rescued pup.

“Sometimes people think, well, we don’t live near the coast, how can I make an impact?” said Vens-Policky. “I think bringing these surrogates in reminds us that you don’t have to be on the coastline to make an impact. There are hundreds of different ways that you can support animals in the wild.”

nschoenberg@chicagotribune.com