It’s extremely rare for a sea otter to give birth to twins.
So when that happened in Morro Bay harbor June 23 or June 24, the mom and her pups enchanted onlookers and caught the attention of marine mammal researchers, who began closely monitoring the trio.
Only 1 to 2 percent of female otters give birth to twins, and few of those babies survive to maturity.
Researchers assume that the pup in Morro Bay they can no longer locate got separated from its sibling and mother, or was abandoned, which are the usual results when otter twins are born.
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Marine researchers believe the remaining pup is still with its mother.
“I don’t think they (biologists) have ever seen a mother being able to successfully raise two pups. Her metabolism and her body only have enough energy to raise one,” said Lisa Harper Henderson, site manager for The Marine Mammal Center’s Morro Bay triage facility, which stabilizes and treats injured and ill marine mammals, most of which are then transferred to a larger facility in Sausalito.
An otter’s food intake must equal 25 percent of its body weight every day, according to the Defenders of the Wildlife website. It’s a strain for a mom to provide food for herself and nurse or feed one pup; feeding two pups is almost impossible.
In addition, the female, who functions as a single mom, acts as cradle, groomer and defender for months.
Even though marine experts expected that one pup wouldn’t survive, they couldn’t take pre-emptive action and could only hope the likely separation would happen while they were closely observing the trio. The scientists had planned to capture the abandoned pup and take it to the Monterey Bay Aquarium’s Sea Otter Research and Conservation program (SORAC).
Michele Staedler, a scientist with the aquarium’s program, was one of those keeping tabs on the mom and twins.
But when dense fog blanketed the area the evening of June 25 and the next morning, Staedler and the others lost sight of the trio.
After the fog lifted, observers have seen a female they’re relatively sure is the mom, but she has only one pup.
Determining whether an abandoned pup is a twin is difficult, unless observers see the mom leaving the baby.
“In SORAC’s 29-year history, we can confirm that we’ve raised one otter, Milkdud, who was an abandoned twin and was raised here at the aquarium,” staying for nearly a decade, according to Angela Hains, aquarium spokeswoman.
Recently, while the Morro Bay mom and two little ones were floating in the bay near Target Rock — southeast of Morro Rock — they captivated onlookers, who oohed and aahed over the beguiling trio.
Mike Baird, a State Parks docent and amateur photographer, took several images of the rare infants and mom. He wrote in an email that, “in taking the photo, I knew I was witnessing a rare natural event,” so he “concentrated on documenting the most clear and interesting photo of potential scientific value.”
Pat Harris of San Luis Obispo was in the area with grandson Liam. She emailed a friend that “the twins were apparently born Saturday, so (were) just a couple of days old. We were there when Mike (Baird) arrived to take pictures.”
She wrote that “there were lots of people watching on shore, and some kayakers and tour boats, but they kept their distance. There were some male otters floating around, too — the mom deposited the two babies on some kelp (she was taking a well-deserved break), and one of the males started over. The mom went ballistic — attacked him in a heartbeat, and he slunk off.”