What Happens To Stranded Sea Otter Pups?
If you frequent the Internet, you've probably seen pictures or videos of an adorably fluffy baby sea otter popping up all over the place. (And if you haven't, do yourself a favor and check her out. But then come back here.) Pup 681, as she's known, was rescued after being found alone at just a week old on the California coast, and now lives at Chicago's Shedd Aquarium. But this isn't the first time an orphaned pup has had humans come to her aid. We talked to Karl Mayer, Animal Care Coordinator at the Monterey Bay Aquarium, about the procedure for responding to live stranded southern sea otters and how Pup 681 ended up at Shedd.
Although they're not responsible for physically retrieving every animal, Monterey Bay Aquarium along with the Marine Mammal Center coordinates the response to reports of stranded sea otters. In that capacity, the Aquarium deals with 50 to 60 sea otters every year. Only about 20 to 30 percent are pups; the rest are sick or injured adults. If the injuries are treatable, or the illness curable, these adults will be cared for and re-released—but often humane euthanization is the only recourse. Here's what happens when the otter in need is a pup.
Option 1: Find Mom
The first step is look for mom. "We rarely actually know what the reason for the separation is and so the default is to assume that it was an inadvertent separation from mom and that there may be an opportunity to try to effect a reunite," Mayer explains. "When sea otter pups and moms are separated, they're both vocal, so if there’s a vocalizing adult somewhere off shore, and we find a vocal pup on the beach, if we can get the pup close enough to the mom, she’ll be bold in terms of their willingness to come pretty close to grab a pup."
About 10 percent of stranded pups are successfully reunited with their mothers, but the window to find mom is very small—after just a few hours, she will give up the search. When Pup 681 was first reported, night was already falling and so, unable to move her in the dark, Mayer's team decided to leave her on the beach overnight in the hopes that her mother would return. When that didn't happen, the team considered the next best course of action.
Option 2: Surrogacy
"Option number two would be to place it with our surrogacy program," Mayer says. "Our method for rearing stranded pups for release back into the wild includes pairing them with one of our permanent captive female sea otters on our exhibit." Although it's not where Pup 681 ended up, this program is worth a deeper look.
In 2001, Monterey Bay Aquarium rescued a pregnant female sea otter suffering from toxoplasmosis, a parasitic disease with symptoms including neurological impairment and unsuccessful pregnancies. Shortly after her rescue, the female gave birth to a stillborn pup.
"Amazingly, just 24 hours after she had given birth to that pup, a two week old male stranded just right here in Monterey. And because of that fortuitous connection, we basically said, 'Hey, let’s try putting this pup right in,'" Mayer says. The female took to the pup right away and immediately began caring for him. In the past, the Aquarium staff had tried hand-rearing stranded pups, but they had little success re-releasing these animals because they were too bonded to humans.
"When you tried to put them out in the wild they would end up interacting with either divers or kayakers," Mayer says of these earlier attempts. "Eventually we would have to make the decision that this animal is either going to cause harm to somebody or the person is going to cause harm to the otter and they would wind up having to be brought back into captivity." But seeing the female act as a surrogate mother to the orphaned pup gave the team an idea for an entirely new procedure. "It opened this whole new realm of possibility of working with them, taking ourselves out of the equation as much as we could."
These days, pups don't immediately get handed over to the female otters for care. Unlike the original surrogate, which had carried a pregnancy to full term, the animals currently on exhibit are not hormonally primed to care for an infant—they're not lactating. So until the pup is 6 to 8 weeks old, the Aquarium staff is responsible for bottle feeding, introducing solid food, and teaching him or her rudimentary food foraging.
"We don’t necessarily know if the female is going to feed the pup," Mayer says. "That being said, among the behaviors that we typically see from the females that are in this role, that are the maternal behaviors, food sharing is often one of the first things that we see. The female will be diving down feeding and the pup will swim up and be curious about what the female is eating and that actually stimulates the female to offer food to the pup."
The rest of the care all sounds pretty cute, too. "The female will carry the pup around on her chest, groom the pup, and she’ll sleep with pups resting on her chest," Mayer says. "Actually, as the bond progresses, fairly frequently we’ll see the pup starting to attempt to nurse on the female."
Pups stay with their surrogate mothers until they're around six months old, which is the same age weaning would take place out in the wild. At that point, they're fitted with flipper tags and surgically-implanted abdominal transmitters that allow the Aquarium to track the success of these orphans. So far, the results are good. Since the program began, over 30 pups have been raised and released this way and, according to Mayer, "the survival rates of those pups and the reproductive success of female pups is essentially the same as for any all-wild counterparts."
Option 3: Other Aquariums
Monterey Bay Aquarium has five permanent female sea otters. During the several months of surrogacy, these females are kept behind the scenes—which means that to keep at least three otters on the exhibit at any one time, only two can be raising stranded pups. When Pup 681 was rescued, "essentially, the inn was full. We’ve already got two females with dependent pups," Mayer says.
Finding a home for Pup 681 could have been tricky: There are very few facilities in the United States prepared to care for sea otters. In captivity, a typical sea otter will eat about 20 percent of his or her body weight a day. With females growing to about 50 pounds and males reaching 60 to 70 pounds, that's a lot of seafood. And their diet isn't cheap; things like clams, shrimp, squid, crab, and mussels make housing a sea otter almost prohibitively expensive.
Fortunately, Shedd Aquarium stepped up and offered to raise and house Pup 681, and the rest is adorable Internet history. Watch her arrival to Shedd here: