As Hal Markowitz recounts in Behavioral Enrichment in the Zoo, date (1981), he was trying to set up a game for mandrills (Papio sphinx) in a Hawaiian zoo. It was a button-pushing game. Fast reflexes won. The goal for the mandrill was to push a lighted button on a console before a zoo visitor could push the button on a matching console on the other side of the barrier. This game had been a big success with Blue, a mandrill in another zoo. Blue was fast, he knew it, and he enjoyed proving it.
But the arrival of mandrills at the zoo was delayed, and Markowitz was asked to adapt the equipment for spider monkeys (Ateles ater). Spider monkeys spend most of their lives up in trees. Their hands are less well suited to pushing buttons. (That's why your spider monkey friends never text you.)
Markowitz's team hung a rope next to the apparatus, so a spider monkey climbing on the rope could reach a hand over to push the button. Only one spider monkey was interested, and her technique was to dangle, and push the button with her nose. She was fast enough to beat lots of hand-using humans.
At the Portland Zoo, another experimenter decided to study “ratio strain” in camels. Since camels have no hands, it was thought in this case that the nose was the appropriate thing for the animals to use. When a panel lit up, camels were to push it with their nose to get a delicious pellet. (No competition with visitors was involved.)
The idea was to see how seldom you could reward the camel before you reached “ratio strain,” the point at which the animal stops responding so often or at all, and perhaps shows “an increase in emotional behavior.” If an animal will push a button if it's rewarded every other time, what if it's only rewarded one time in ten? One time in a hundred? In other words, unseen powers move the goal posts, and the players get visibly peeved.
The camel Adolph monopolized the equipment. As the ratio became less favorable, Adolph devised a new tactic. He'd stick out his chin and vibrate it rapidly, pushing the button with great frequency. With this fast fighting technique he was willing to play even when he got a pellet only once for every 150 chin wiggles.
Markowitz wanted to make an apparatus that could be used by all kinds of animals. All they had to do was touch one of two steel plates situated below two lights. “I envisioned that snakes could sidle up alongside the detector and trigger it off, that elephants might choose to touch it with their trunk or rub against it with one of their legs, and so forth.”
The first player was to be Gabriel, a charming young elephant living in the children's zoo. Perhaps my predictable narrative method has tipped you off that things did not go as expected. Gabriel solved the problem by squirting water from his trunk between the response panels. This shorted them out electrically, “so that a response on either side paid off.”
They tried to prevent this by emptying Gabriel's water trough before the experimental session. Then long before the session. Then long, long before the session. But crafty Gabriel stored water in his trunk. No matter how long they kept the trough dry, he was always ready to tamper with the equipment.
So much for the Universal Device.