This week, shortly after her 60th birthday, Colo, the first gorilla born in human care, died in her sleep. Part of the reason she lived so long — about 20 years longer than gorillas born in the wild — is because of the care she received.
In zoos today, keepers work to reduce the stress of caregiving by training animals to be a part of their own care. Gorillas drink from bottles. Rhinos learn to get their teeth brushed. Lions are trained to get vaccines.
The shooting of Harambe at the Cincinnati Zoo last May spurred debate about whether animals like gorillas even belong in zoos. But most zoo animals won’t be leaving anytime soon, and they require care that emphasizes their welfare if people want them to have long lives like Colo.
It wasn’t always the case that zoos emphasized stress reduction in tending to their nonhuman charges. Animals were sedated, anesthetized or motivated with fear and dominance. Consider elephants. Back in the day keepers and elephants stood dangerously close to one another as part of a method called free contact. With this method, a keeper could motivate an elephant to do what was wanted with inhumane tools like food deprivation, prodding with bullhooks or roped restraints, said DJ Schubert, a wildlife biologist at the Animal Welfare Institute.
Continue reading the main storyNot all zoos have fully abandoned some outdated methods of managing their animals’ health. But the larger, accredited ones have taken lessons from updated methods for training elephants, and more animal trainers are using behavioral principles of learning and memory to shape behavior with rewards, reduce dangerous contact and allow animals some control in their own care.
“We’re not going to be able to emulate what animals do in the wild,” said Dana Hatcher, a nutritionist at the Columbus Zoo and Aquarium in Ohio, where Colo lived. “But we are trying to do things that help recreate these natural behaviors to the best of our abilities.”
These are some of the ways animals in zoos and related dwellings can take part in their own care.
Gorilla See, Gorilla Do …
In human care, a mother gorilla may not want or be able to care for her young. To get past this, zookeepers, like those at Columbus Zoo and Aquarium, become gorilla surrogates who stay with infants at all times.
As part of a surrogacy program, human surrogates mimic the behavior of real mother gorillas. They cough like a gorilla when a baby does something out of line. They carry babies on their backs while crawling on their hands and knees. And just as mother gorillas do, the surrogates leave bits of food around their chest area for the baby to take. Through observational learning of these activities, gorillas that could become foster mothers to these infants learn behavior to take over their care.
… And Gorilla Drink
Zookeepers minimize human contact with the gorillas at the zoo by training infants to approach bottles rather than just receive them. The trainers do this by slowly putting the bottle farther away from the baby until it learns that it must get its own food.
Lions Learn, ‘This Won’t Hurt a Bit’
Animals in human care need shots or vaccines. And just like many humans, zoo animals do not like needles. But they can be trained not to mind.
Getting lion cubs to tolerate needles for vaccines, for example, takes a lot of tiny, incremental steps. Often this starts when a trainer pairs a noise-making device called a clicker with a reward like food so often that the clicker eventually becomes an indicator of reward. Through behavioral shaping, the trainer can then click to reward every time an animal performs a behavior more and more like what is desired.
To get lion cubs used to being around needles, trainers present a tiny, capped needle to the animal, then a bigger one, and so forth. Every time the animal allows this to happen, it receives a reward. The process can take a few weeks to months, depending on the animal.
And to reduce fear of needles, trainers may expose a cub to a needle 100 times, and poke it only once. Within a year, the lion takes vaccines without much fuss.
“They lean their shoulders into the keeper and the keeper injects the vaccine. It’s effortless, and it kind of looks magical,” said Adam Felts, a curator of African animals at Columbus Zoo and Aquarium. “The animals say: ‘Thanks. Can I get my food?’ And they walk away.”
Giraffe Pedicures and Rhino Dentals
Through a procedure called target training, giraffes learn to associate a tennis ball on a stick with a reward, and to move different body parts in the direction of that target. A giraffe can follow a target and learn to put its foot on a block to receive hoof care.
Through more shaping and rewards, black rhinos learn to let caregivers brush their teeth to prevent gum disease. By rewarding them with a big scratch, trainers can get them to hold still for dental care. In a similar way, keepers train polar bears to tolerate nail trims and eye drops.
“They learn to cooperate. It’s kind of like a mutual agreement between the trainer and the animal,” Mr. Felts said. “When you’re training, you’re giving them things they want, and they learn over time and repetition that the keepers are able to do things with them to help assist with their care.”
Marching to Bullhorns and Bells
More than a dozen African species live together in a big field the Columbus Zoo calls a savanna to mimic the real one in Africa. When the weather is bad, or the animals need vitamins or checkups, they must return to the main zoo one species at a time, or stampedes and other dangerous events can occur.
By pairing the sound of a musical instrument with a reward like food, the animals learn that when that sound is heard, it is time for their species to congregate and move in. Lions respond to a bullhorn. Giraffes respond to a bell. And the wildebeests, which are always last to go inside, come to the shake of a tambourine. Some of the animals are so well trained that they start lining up as soon as they see the keepers’ vehicle pull into the savanna.
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