Adult Sea Otters Are Adopting Orphaned Babies at the Monterey Bay Aquarium

The Monterey Bay Aquarium has perhaps the most heart-warming aquatic program in the country. Adult sea otters are adopting orphaned baby sea otters and helping them grow up before they are released back into the wild.

The Californian aquarium has been rescuing sea otters since 1984. But in 2002, they developed a different technique to help rehabilitate pups before releasing them back into the wild. Instead of having humans handle the rescued otter pups, they gave them to a “surrogate mom” who would teach them vital survival skills.

A study published in the nature journal Oryx last week confirmed that the otters raised by surrogate moms “are surviving as well as their wild kin—and the resulting bump in the otter population at Elkhorn Slough is helping to restore the estuary ecosystem.”

Pups who were rehabilitated by zoo staff often became too used to human interaction to be safely released back into the wild.

But the aquarium’s rehabilitation approach changed in the early 2000s when a pregnant otter came to the aquarium. Shortly after her arrival, she delivered a stillborn baby. Within 24 hours, an orphaned pup arrived at the aquarium and was placed in the same tank. The mother quickly “adopted” the young pup and a bond was formed.

When another pup arrived, aquarium keepers matched it with another female and a similar thing happen. In all of the aquarium’s attempts, a bond forms between mother and the adopted child about 80 percent of the time.

One of the aquarium’s most successful foster moms is named Rosa. She came to the aquarium as a pup herself and was rehabilitated. But when she was released back into the wild in 2000, she had grown too attached to humans to fend for herself. She would swim up to fishermen expecting food so the aquarium brought her back, according to CNN. She will turn 20 years old this year. In her lifetime, she has fostered 15 pups. She is now retired from the program but still swimming at the aquarium.

"Sea otter pups are born in the wild and essentially they have no survival skills whatsoever," Karl Mayer, the animal care coordinator for the aquarium, told USA Today. "They're little corks on the surface of the ocean, they've got very bland fur, they're totally dependent on the mother for essentially 100% of everything that they do.”

Having a sea otter foster mom step in allows the otters to learn life skills while still maintaining its wildness. And it’s been a wild success. From 2002 to 2016, staff released 37 surrogate-reared pups back into the wild. More than half of the otter population growth in the area is now attributed to the surrogate-raised pups and their progeny.

The aquarium hopes that if the surrogacy program expands to other aquariums, they will be able to revive the sea otter population, which has been listed as a threatened species since 1977.