Excerpt
Stacey Tabellario and Mindy Babitz are like many new mothers. They are with the baby every second she’s awake. They watch her on a monitor while she sleeps. They prepare bottles, talk to her and carry her and get little sleep themselves.
But the baby is a sloth bear (think Baloo from “The Jungle Book”), the only one of its kind born in captivity in the United States this year. And she is in Tabellario and Babitz’s care for a reason that’s simple and hard to dispute: when she was born, her mother ate her siblings.
“Now we’re mom,” said Tabellario one of the six zookeepers caring for the cub. “It’s an amazing experience, and we’re learning a lot, but there is still that bittersweet tone to it, because we all know that the first choice for any animal is to be raised by their mother.”
At first, zookeepers were thrilled when Khali, named for the Hindu goddess of destruction from the bears’ native India, gave birth to three cubs, an unusually large litter for a sloth bear.
But the first was stillborn. She consumed that cub immediately. A week later, she ate the second and began neglecting the third.
Tabellario says Khali’s reaction was normal, even healthy for a mother bear.
“It sounds very shocking, but it’s not something that shocks us as keepers. That’s the natural history of carnivores.”
It sounds counterintuitive to evolution, but infanticide in the wild is well-documented, said Doug Mock, professor of biology at the University of Oklahoma and author of a book on the subject. Animal parents have limited resources to dedicate to their offspring, he said, and if the baby is sick or weak, carnivores have been known to consume babies or abandon them. Cannibalism gives the mother the calories she needs to raise her healthy babies or get pregnant again.
That may have been the case for Khali, Tabellario said. A necropsy of her second cub revealed that the cub had a parasite in its intestines, which Khali may have sensed. When the keepers pulled the surviving cub from the den, she was ill too.
Sometimes it’s the mother or father that kills; sometimes it’s the siblings. Mock remembers watching a group of egret chicks peck their sibling to death, while their mother stood idly by, cleaning her feathers.
“It’s the most startling thing I’ve ever seen in the field,” he said. “I literally sat and watched and thought, ‘Any second, the parents will step in and stop this.’”
When asked him how he felt witnessing this behavior: “My soul died,” he said.
Mock has seen birds push their chicks from the nest, abandon them, even starve them. In the animal kingdom, he says, infanticide is not about pathology. It’s about ensuring that the strongest offspring survive.
“It’s one of the less pleasant aspects of nature, something humans don’t like to think about. You want to think of nature as warm, cuddly and fuzzy,” he said. “We assume that other species look at offspring the same way we look at offspring… To us it seems as if (infanticide) must be some sick kind of thing, but it isn’t necessarily.”
Infanticide can be accidental, too, said Susan Margulis, associate professor of biology at Canisius College.
“The thing that people don’t realize is that most young animals die. Most die when they’re in infancy. Animals mostly raise two babies to adulthood. It’s just more noticeable in zoos,” she said.
That’s because motherhood has a learning curve, she said, and it doesn’t come to all animals naturally the first time. She worked with primates in zoos, and found that new mothers must learn how to nurse their young, and how to properly care for them.
“I’ve seen primate mothers that were good enough, but not great. Sometimes good enough is okay,” she said. “That first breeding attempt is a learning experience. You almost have to assume it’s not going to go well. In evolution, that very well could have been the case for humans ancestors as well.” She added, “Even human mothers need to work out details of how to do this new job that they may not have any experience with.”
Zoos can’t always wait for mothers to figure it out. That was the case for Ally, a cheetah at the National Zoo. This winter she gave birth to a litter of four cubs. At first, keepers breathed a sigh of relief, said Copper Aitken-Palmer, chief veterinarian at the National Zoo. The new cheetah mom was nursing and grooming her cubs normally. But three weeks later, zookeepers noticed that Ally was carrying her cubs in and out of the den more than normal. The cubs became lethargic, but Ally continued to pace with them.
Adrienne Crosier, who manages the cheetah breeding program at the Smithsonian Conservation Biology Institute, says the keepers typically leave cubs with their mothers for as long as possible, but something was clearly wrong.
“She was carrying them because she was nervous and agitated, and we do see a lot of very nervous behavior in first-time cheetah moms,” she said. “It was kind of a difficult situation because every time we tried to treat them it made Ally more agitated, which then made her want to carry them more, which then exasperated the injuries.”
Ally had bitten down on the scruffs of their necks too roughly, causing deep wounds which had become infected, Aitken-Palmer said. She estimates the zoo had a few hours to save the cheetah cubs. On Christmas Day, keepers made the decision to take the cubs away from Ally.
“She went from a nervous mom to inadvertently doing mortal damage to these cubs,” Aitken-Palmer said. “We pretty quickly figured out that these cubs weren’t going back to their mom. And they may not make it at all. They were septic with very low glucose, which is blood sugar. The female actually came in seizuring, her blood sugar was so low. Frankly, I’ve not turned around a lot of neonates that were in that condition.”
One of the cubs died. The other three underwent three major surgeries each and hundreds of stitches over the following weeks. The cubs weren’t weaned, so they still needed milk and multiple feedings every day.
When animal mothers neglect or try to kill their own young in captivity, hand-rearing is one option, Margulis said, one that zoos utilize less than they did 30 years ago. Though in some cases, animal parents are so notoriously neglectful or the species is so rare, hand-raising becomes the first option.
