The Pros and Cons of Hand-raising Zoo Babies

Calf klipspringer and zookeeper
Photo courtesy of Lincoln Park Zoo
A zookeeper at the Lincoln Park Zoo feeds a calf klipspringer.

Other cases require more effort. When a baby gorilla was injured at the zoo, the staff came up with ways to reduce the impact of her recovery from surgery. "We housed her separate from the other gorillas but kept her in direct proximity to her family group so she was never out of sight of other gorillas," Bernier says. And while it might seem irresistible to coo and cuddle with a baby ape, the staff also tried to minimize her exposure to human activity like talking. Keepers taught the young gorilla to come to the mesh of the enclosure and take food, so they could supplement her diet when she rejoined the group. That allowed them to return her to her family as early as possible, which is always their goal. "Especially with mammals and critically with social animals, we try to minimize the amount of time that the animal is away from its dam or conspecifics," Bernier says. "We work hard to get everyone stabilized and work toward introducing those animals back into the group."

Providing a Better Upbringing

Although many babies are hand-raised as a substitute for natural mothering, there are cases in which keepers provide care that the young wouldn't get in the wild. Many bird species lay two eggs but routinely raise only one baby to adulthood, either because the parents give only one nearly all the care or because the chicks compete, eventually to the death. But in the zoo, keepers pull the second chick and raise it.

They take the step especially if the animal is critically endangered or extinct in the wild, like the Micronesian kingfisher. "In that population, every individual has a high value, so we wouldn't want even a natural process like chick competition to get in the way," Bernier says. However, they do the same thing for the ones that aren't rare, because zookeepers care about individuals as well as species. "A nestmate that is being under-attended to or forced out of the nest, we will also hand-raise that animal because the individual animal's welfare is the critical concern," he says.

Some babies that wouldn't get any parental care at all in the wild get individual attention from keepers. Reptile eggs are normally removed from enclosures and artificially incubated, resulting in tiny creatures that need special care in captivity — like the smooth little green snakes that the zoo is hatching for release for a conservation project. The zoo is making sure to have insects small enough for them to eat — and nutritious enough for a growing baby. "The nutritionists have designed diets for the insects that we feed out," Bernier says. "We have to feed the insects the right food to make sure they're a proper diet and not just empty calories [for the snakes]."

Creating Tolerant Adults

While Lincoln Park, among other zoos, only hand-raises babies for health reasons, there are cases elsewhere in which other considerations come into play. For instance, with the clouded leopard, hand-raising has not only reduced high infant mortality but has also proved to be important to breeding the animals in captivity. The difficulty has been that when paired for mating, one of the leopards often would end up dead.

"With clouded leopards, the big problem is the males are generally about twice the size of the females," says Karen Rice, supervisor of carnivores and anteaters at the Nashville Zoo. "And they're so agile they can go just about anywhere — up, down, sideways. There's a lot of chasing. It's not a pretty scenario."

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