Conditional Behavior
“Target,” says
Nicole Kehl, lead keeper at the McCormick Bird House. The Blyth’s
hornbill flaps his wings and with a whoosh descends from
a high perch in the exhibit. Kehl extends a stick with a grape
at the end, and the hornbill gently plucks it off.
Kehl snaps a hand clicker and says, “Good boy!”
She then moves the target – a round white plastic lid attached
to the end of another stick – and calls out, “Target.” The
hornbill flutters lower and taps the target once with its beak.
Kehl snaps her clicker and simultaneously hands out another food
treat as a reward. This is crucial: The clicker, or in some cases
a whistle, “bridges” the time between the right behavior
and the reward. The animal learns to associate the click with doing
well. If the click comes too late, the animal might learn an undesirable
behavior, for example, pecking at the target instead of touching
it once with its beak.
Kehl repeats the sequence several times, until the hornbill alights
on a scale that’s been placed on a tree stump. In effect,
the bird has voluntarily weighed itself, without a keeper having
to touch the animal.
This is operant conditioning working at its optimum.
Keepers use operant conditioning to encourage animals to participate
in their own daily care. Using positive reinforcement principles
such as rewarding a desired behavior with food treats, a bird can
learn how to land on a scale, a chimpanzee to present its arm for
a vaccination, a zebra to raise its hoof for inspection.
At the Helen Brach Primate House, Area Supervisor Andy Henderson
hooks a flat blue plastic circle six inches in diameter to an enclosure
off-exhibit. With a dog whistle in his mouth, he picks up a bamboo
stick. He nods to another keeper and the door separating adjacent
holding areas is opened. A male drill named Max bounds in and plops
down in front of the blue target.
Henderson stands outside the enclosure and taps it with his stick.
As the drill extends his hand to touch it, the keeper blows the
whistle and feeds Max a piece of potato. Henderson next places
both of his hands on the enclosure above the drill’s head.
Max stretches to his full height and pats Henderson’s hands.
The keeper blows the whistle and the drill receives a piece of
fruit. Henderson then puts his right hand on the enclosure. Max
reaches for it.
A whistle and a treat.
What might look like play is not a game. Behavioral
enrichment is, in fact, an important tool for zoos around the country
because it often eliminates the need to anesthetize an animal,
reducing potential medical complications and stress. Seals touch
targets with their noses while keepers medicate their eyes, rhinos
stand still at a fence allowing a veterinarian to draw blood from
an ear vein. Other species learn similar behaviors.
“Free contact,” the long-practiced method for handling
some animals that involves direct contact with the animal, has
given way to “protected contact,” in which a barrier
or a respectful distance remains between animal and keeper. Protected
contact reduces stress caused by human interference and allows the animals to have a choice.
“It’s all about getting positive behavior from the
animals,” says Meg Hudson-Dye, a consultant with Animal Management
Resources in LaGrange who trains zoo staff in operant conditioning. “One
of the keys is setting up the animals to succeed. It’s like
a schoolteacher creating a lesson plan that sets up children to
learn. And it has to be done voluntarily by the animals. Sometimes
you can tell by their body language, like the pitch to a giraffe’s
ears, that they’re not ready to cooperate.”
“What we try to do is capture natural behaviors and
redirect them to things that are useful for the animal,” says
Kathryn Gamble, D.V.M., the zoo’s director of Veterinary
Services. “We’re not teaching them tricks. That’s
the big difference between training and operant conditioning.”
Animal keepers say operant conditioning promotes a higher quality
of life for the animals.
“When we start working with animals at a young age, they
have no built-in fear of their keepers,” Henderson says. “Conditioning
has been part of their routine all their life, so they learn quickly.”
Keepers and veterinarians
follow a manual of signals, or cues, to maintain consistency and
effectiveness.“It must be clear to the animal
what is being asked,” says Gamble, “because you can
easily and inadvertently condition a behavior that you don’t
desire. And that could be dangerous.”
Operant conditioning has changed – for the better – the
relationship between veterinarians and zoo animals. “Many
times our entire interaction before operant conditioning was when
animals were sick,” Gamble says. “So it became almost
a learned behavior that when a vet appeared, the animal didn’t
feel well. Now, because veterinarians are part of the program,
the animals see us in a positive way, or at least in a non-negative
way.”
Kehl says that operant conditioning might have saved the life
of a fairy blue bird in the free-flight exhibit. Keepers had conditioned
the bird to walk into a shipping crate. One day they discovered
the bird was seriously ill. They placed a crate in the exhibit,
and the weakened bird crawled into the crate on its own. It was
then transported to the zoo’s hospital for an examination.
“Had we gone in and handled that bird, it would have caused
increased stress,” Kehl says. “This is the perfect
example of why we do operant conditioning.”
It turned out the bird had injured its wing, couldn’t fly
and wasn’t eating. With treatment, it eventually recovered
and is now back home in the free-flight exhibit.
Keepers also teach large, dangerous animals, such as a tiger, to
walk into a shipping crate. There often is no need to tranquilize
it, but if it does become necessary, the animal will accept an injection,
having been conditioned by keepers, who use blunt needles to get
the animal accustomed to the procedure.
“Operant conditioning doesn’t replace some of the
procedures we do as vets, like immobilizing and surgery,” says
Gamble, “but it’s a tool that makes what we need to
do more comfortable for everyone.”
– Freelance writer Fawn Ring contributed to this story. |
