The Nature of the Beast (according to Susan McCarthy)

What shall I do with this prehensile tail?

I had heard that the Audubon Zoo in New Orleans was a really great zoo. The people who told me this (not zoo aficionados) were never able to say what was great about it. They didn't mention rare species, successful breeding programs, or brilliant enrichment schemes.

It was just really great.

I recently got to go for the first time, and I think I know the reason for their enthusiasm.

Frozen daiquiris.

They sell these along with the usual fast food available at American zoos. I asked the server what was in them, thinking maybe it was some sort of lime soda. She found the question strange. “Rum?” she said.

I shouldn't have been surprised. New Orleans is the wettest town I know, one that could have a banner at the airport reading WELCOME SLOPPY DRUNKS. It just hadn't occurred to me that this spirit extended to the zoo.

Shocked, I purchased a daiquiri and set out to see some animals.

I am interested in zoos. I loved the giant anteaters, who were milling around madly, awaiting their chance to go back into their night quarters.
 

The humans were like zoo visitors everywhere, inclined to stand next to a large sign that explains that orangutans are not monkeys but apes and say “Look at the monkey, Jesse!” Yet they were less frenetic than usual, maybe because of the heat. In the languid humid air, people swanned dreamily along the paths. Some were clasping icy beverages. Perhaps the slow aimless pace of the visitors is less jangling to the animals.

While walking around the pond in the South American Pampas exhibit, I heard a splash. I turned to see a rhea hastily climbing out of the water. The other rheas seemed  fascinated and started following the damp one. (What was it like? Was it fun? Was it cool? Did you float? Are you gonna go in again? Go in again! You should go in  again!)



Was the rhea imitating the ducks in the pond? No. Later investigation revealed that rheas are known to swim. Darwin saw rheas swim across the Santa Cruz River in Argentina. So this zoo-born rhea was experimenting with a skill used by its wild relatives. That was interesting.

Finally I arrived at the spider monkeys (Ateles geoffroyi). 
The large exhibit, modeled on Central American ruins, was good to look at and, more importantly, full of things  a monkey can do with a prehensile tail.

If you had such a tail, you could hook it over something.  Or twine it along something.
   

You could use it for balance, like an outrigger,  or for artistic emphasis.


You could use it to carry things, even if all you have to tote is a bunch of grass.

  In a vision I now imagine the Audubon zoo extending its hospitality to its occupants. I behold anteaters even more avid to get into their evening quarters, where frosty beverages are served. I suppose that an individual with a prehensile tail is perfectly fitted to stroll a slack rope while holding a daiquiri. Dreamily, I even wonder if this policy hasn't already been implemented. Unscheduled swimming is the sort of thing alcohol often inspires in young creatures.

What a great zoo.

Three hacks

The experimenters were trying to enliven the lives of zoo animals while simultaneously gathering data. As often happens, not all the data they gathered was in the categories expected.

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.

 

I'm still in the dark. Fortunately, I'm nocturnal.

Update on the SF Zoo's tool-flourishing aye-ayes:

I recently got a short tour of the normally-closed nocturnal house. This now houses an elderly mouse lemur and a thriving aye-aye family. Sabrina and Warlock produced a son, Dobby, who looks just as eccentric as his elders. He is only the 2nd second-generation aye-aye born in the US, so the Zoo is extremely proud of him. Asked how they accounted for this success, our guide said that it seems aye-ayes like to mate high in the trees, and the nocturnal house has a high ceiling which can be utilized for this romantic purpose.

Several months ago, to general surprise, Sabrina and Warlock produced another baby. It had been expected that it might take the couple five years to have their next child, not just one year. (Ah, high ceilings...) This daughter is allegedly still unnamed. (I find this unlikely. I suspect she has a name but it is being kept secret for one or more of the usual bizarre zoo rationales for withholding such non-Nature Facts. Or they are just embarrassed that they named her Morticia or Grimalkin or whatever.)

I asked about the wrench. “Oh yes,” said the guide. “We give them wrenches for their teeth.” It seems that aye-ayes have ever-growing teeth, like rodents, and need hard objects to gnaw on so their teeth don't overgrow. For this purpose they are given bamboo and hard wood. And wrenches.

The guide, who does not appear to have been at the Zoo very long, seemed to find this perfectly mundane, and offered no explanation for how wrenches came to be the dental device of choice.

(“Sure, we give the aye-ayes wrenches for teething. Just like we give the otters eggbeaters for grooming, and we give the pelicans assault rifles for nest-building. It's environmental enrichment.”)

Until I get a different suggestion, I am sticking with the hypothesis that this practice originated in an aye-aye act of pilferage.

Spotty isn't really being challenged by the curriculum

Afternoon at the zoo. Fake savannah, real giraffes. Fake rocks, real plants. In a real crevice on top of a fake cliff, real weeds growing in real dust.

Child: “That giraffe is sleeping on the rock!” It did look as if the giraffe had approached the simulated sandstone cliff and laid her head along the top of it for a rest. Actually the giraffe was straining toward the weeds in the crevice, almost out of reach of her outstretched tongue.

They can't be that delicious. It must be a project.

Vigorously Support the New Turtle Diet!

As far as we know there are fewer than half a dozen Yangtze giant soft-shelled turtles left in the world and only one is female.

The Yangtze giants (Rafetus swinhoei) are hard to overlook, since they get to be more than a yard long and can weigh a couple of hundred pounds. That means they've been easy to hunt -- and perfect for feeding a crowd.

When it was realized how endangered they were, a search was launched for survivors. A male was in the zoo in Suzhou, China. He's thought to be 100 years old. Two more males were found in Vietnam.

When keepers at the zoo in Changsha, China, got the mailing about the turtles, they said they had a turtle who looked a lot like the one in the picture.... She was thought to be 80 years old. The Changsha turtle, now named China Girl, is indeed a Yangtze giant soft-shell, and was shipped to Suzhou to meet the male there. Neither had seen another turtle of the opposite sex in decades.

China Girl and her new friend knew exactly what to do, and there was much rejoicing when China Girl laid eggs. (I am trying to tell this story tastefully, and avoid the “Ha ha, sexy oldsters!” tone found in much of the coverage. So please keep in mind that these turtles appear to be longer-lived than we are, and for us to snigger about them might be like nine-year-olds groaning and pretending to vomit when they see college students holding hands.)

Though many of the eggs were fertile, not one hatched. Turtle experts blamed years of a low-calcium diet. China Girl had been fed beef and pork. A more suitable and calcium-rich diet would be fish and crayfish. Xie Yan, who runs the Wildlife Conservation Society's China program, says China Girl's diet has already been changed. “Next time will be better.” Lie Jinde, director of the organization that manages the Suzhou Zoo, says “Wait until next year. We ought to succeed.”

At Suzhou, the turtles are protected. There's a guard, a surveillance camera, and bullet-proof glass. (Weirdly, there are people who would commit serious crimes in order to own the last female Yangtze giant soft-shelled turtle in the world. Some of them would try to breed her in the same way as the zoo, some would keep her as a trophy, and probably a few of them would make a point of eating the hardest to-get, most expensive, most selfish, and most evil turtle soup in the world.) So those things are needed.

And of course there's the new regimen.  I vigorously support the new turtle diet!

But I would also support making the turtles' lives better in other ways. A turtle can get bored.

Here's the story of Pigface (from Becoming a Tiger):

An unusual example of play in an adult comes from Pigface, a Nile soft-shelled turtle who arrived at the National Zoo in 1940. Six inches long, he was not really pig-faced, but he had the pointy nose and wide decurved mouth appropriate to his species. By the 1980s, Pigface was a yard long, and violently bored. Once a week he received a nutritious dead rat, and twice a week a dozen live goldfish.  The goldfish were the highlight of the week, and he pursued them “with speed and agility,” so zealously that until he caught them all he literally stopped only to breathe.  This filled 20 exciting minutes a week.

In the 1980s keepers noticed that Pigface had begun to bite his front legs and rake his neck with his front claws, hurting himself badly. Suddenly grasping that he might be bored, they gave Pigface toys—basketballs and a floating hoop. This reduced Pigface’s self-mutilation, and he spent hours nosing and biting at the basketballs, pushing them across the water. As for the hoop, he could not only nose it, bite at it, and push it, but also chew it, shake it, pull it, kick it, and swim back and forth through it. Best of all he liked the hose the keepers used when they refilled the tank, enjoying the sensation of the water streaming over his head at exactly the right angle, and playing tug-of-war with the keeper on cleaning day by grabbing the hose and swimming backward with it, pulling it into the tank. (There is no reason to suspect that Pigface was hoping to pull his keeper into the tank, steal his keys, and make a getaway.)

Nile soft-shelled turtles (Trionyx triunguis) are closely related to Yangtze giant soft-shelled turtles. I suspect that what's good for Pigface might be good for China Girl.

Do those safe, well-fed turtles in Suzhou get to chase goldfish? Could China Girl maybe have a hoop? A hoop and a ball? A hoop and a ball and a chance to fight with a hose?

Do happier turtles breed better? It's worth a try.