Myth Busting: The Truth About Animals And Tools

Dec 22, 2011
Originally published on December 23, 2011 11:28 am

A wasp uses a pebble as a hammer. An octopus carries around a coconut shell to hide in. A shrike impales its prey on a sharp thorn.

Those are just a few examples of animal tool use that appear in the new book Animal Tool Behavior by Robert W. Shumaker, Kristina R. Walkup and Benjamin B. Beck. The book updates an edition published in 1980 by Beck. And in the new version, the authors try to dispel a number of persistent myths about animals and tools.

Shumaker tells me about some of those myths during a walk around The Indianapolis Zoo, where he is vice president of life sciences. (He is also a member of the adjunct faculty at the University of Indiana.)

As we approach a female polar bear named Tundra, Shumaker says one myth he hopes to deflate is that tool use is limited to monkeys and apes. Polar bears offer a powerful rebuttal of that idea, he says. In zoos, they often throw objects with great force and accuracy. It's less clear whether this sort of tool use occurs in the wild. But there are anecdotal reports from early Arctic explorers of polar bears using projectiles to hunt.

"One of the stories we have is polar bears getting up on a cliff and hurling great chunks of ice down on something like a walrus to kill it," Shumaker says.

Another common misconception: Tool use requires fingers, or at least hands, Shumaker says. Apparently, no one bothered to tell dolphins. "They have nothing to hold tools with except their mouth," he says, "and yet they are still innovative and creative."

Dolphins play with just about any object they find, Shumaker says. In some cases, the objects are merely toys — but they become tools when used to manipulate another object or creature for a specific purpose. And dolphins do that kind of manipulating a lot, says Jodie Baker, who is in charge of marine mammals at the zoo. As we speak over the din of dolphin splashes and chatter, Baker sees a dolphin named Kimo preparing to manipulate us with a tool — in this case, a buoy.

"If you walk by the pool and there's a dolphin playing with a toy, they'll typically throw it in your direction to get your attention," she says.

That's a form of tool use known as baiting or enticing. But scientists have collected lots of examples of dolphins doing other things with tools, Shumaker says.

"One is a dolphin that found a piece of tile and took it down to the bottom of their pool and used it to scrape algae off the bottom of their pool and then they ate the algae," he says.

And wild dolphins in Australia sometimes flush out their prey with a sponge, he says. "They hold the sponge on their rostrum, and then they use that as they disturb the sandy bottom to get fish like flounder that are down in the sand."

Genetics Or Intelligence?

One of the most widespread myths about tool use is that it is a sign of intelligence. Of course, some really smart animals do use tools. But so do creatures like the bolas spider, which is named after the throwing weapon used by South American gauchos. The spider's version of the bolas is a ball made from the same silk it uses to spin a web, Shumaker says.

"When an insect flies by, they throw it and it attaches to the insect because it's sticky and they reel them in," he says. "It's very complex. Very impressive. Very dramatic. But all available information tells us that it's completely controlled from this animal's genetic history." In other words, it's programmed behavior, not something the spider figured out. Genetic programming is also the reason hermit crabs carry around another creature's shell and ant-lions throw sand at their prey.

When intelligent animals do use tools, though, they often do so in very creative ways, Shumaker says.

At the zoo's spacious elephant enclosure, Tim Littig, a senior animal trainer, points toward a baby elephant named Kalina, who is standing next to her mother, Kubwa. Kalina has been able to nurse without any help, Littig says. But things were trickier with Kubwa's previous baby, he says.

"Her last calf was a little smaller than this one and required a step stool to be able to reach her mammary glands to nurse," Littig explains. "Kubwa would move the stool around so the calf could stand up on the stool to nurse."

Technically, that made her baby the tool user. But it was Kubwa who figured out how to use the tool. And that sort of problem-solving is a sign of intelligence, Shumaker says.

So is figuring out how to make a tool — a skill many scientists once thought of as uniquely human. Shumaker says those scientists must not have spent much time around orangutans. Then he takes me to the orangutan enclosure for a demonstration.

I'm holding a large microphone, which Shumaker reminds me not to point at the orangutans, lest they think it's a weapon. But the animals aren't frightened. Several orangutans reach through the steel mesh and make it clear to Shumaker that they want to have the microphone. Shumaker tells a female named Knobi that she can touch it, which she does several times. When I move it out of reach, though, Knobi walks off and comes back with a small tree branch.

"She's making a reaching tool to try and get your microphone," Shumaker explains as Knobi breaks off one forking branch so the limb will fit through the steel mesh.

But this reaching tool isn't long enough, so Knobi fetches a branch that's 5 or 6 feet long. I stay where I am as Knobi prods at the microphone with the tool.

"She's doing her best to draw the mic in," Shumaker says to me. Then to Knobi he says: "I'm sorry; you cannot have it. Good job with your tool."

As we walk away, we can see Knobi grabbing an even larger branch.

Using Symbols As Tools

Just 10 or 15 years ago, scientists were still debating whether orangutans in the wild also made tools, Shumaker says. Now it's clear they do, and there are several examples in Animal Tool Behavior. The book also offers scientific documentation of other species making tools in the wild. New Caledonian crows make hooks out of twigs to catch prey. Wild chimpanzees make wooden spears for hunting.

Perhaps the most surprising and controversial findings in the new book involve what scientists refer to as symbolic tool use. "These are examples where we see tools being used to represent something else or to provide a change in psychological state," Shumaker says

Symbolic tool use is something people do every time they pay for an item with paper bills or coins. And some monkeys and apes in captivity have learned to use tokens that they trade for various foods.

But Shumaker is more intrigued by the sort of symbolic tools that can affect emotions. There are lots of examples of this in people. Children often have a special stuffed animal or blanket that is much more than a toy. The object represents comfort or security to them, and they use it to feel better.

It's one more behavior that scientists once considered uniquely human. But Shumaker says there is more and more evidence that some animals use symbolic tools in much the same way.

"We would see great apes in times of great stress or sadness, like a female who had an infant that died," Shumaker says. "That female would create something that researchers called a doll and then [she] treated it exactly as she had treated her infant that had recently died."

Shumaker says scientists are still debating the significance of examples like this. But he says the fact that such a debate is even taking place shows how much things have changed since the 1960s, when scientists first realized that humans weren't the only ones using tools.

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Transcript

RENEE MONTAGNE, HOST:

This is MORNING EDITION from NPR News. I'm Renee Montagne.

LINDA WERTHEIMER, HOST:

And I'm Linda Wertheimer. In the 1960s textbooks still described humans as the only creatures to make and use tools. That changed in the '70s when Jane Goodall observed chimpanzees making and using tools. Now a new book tries to catalog the full range of tool use in animals. "Animal Tool Behavior" offers examples from wasps that tamp down soil with a pebble to elephants that throw stones at their enemies.

And the book says a lot of old ideas about animals and tools are simply wrong. NPR's Jon Hamilton visited the Indianapolis Zoo to speak with one of the authors.

(SOUNDBITE OF KIDS PLAYING)

JON HAMILTON, BYLINE: I'm touring the exhibits with Rob Shumaker. He's vice president for Life Sciences here and also teaches at Indiana University.

ROB SHUMAKER: Well, we're approaching our polar bear exhibit and we have this adult female, Tundra, and she is about as beautiful as a polar bear can be.

HAMILTON: Shumaker says one goal of the book which he wrote with Benjamin Beck and Kristina Walkup is to correct some widespread misconceptions, like the idea that tool use is limited to monkeys and apes.

SHUMAKER: We have these great stories about polar bear tool use that are in the historical literature. And one of the stories we have is Polar bears getting up on a cliff and hurling great chunks of ice down on something like a walrus to kill it.

HAMILTON: Well, that's an anecdote. There's no doubt that Polar bears in zoos often throw objects with great force and accuracy. Shumaker says another common misconception is that tool use requires fingers, or at least hands.

(SOUNDBITE OF DOLPHINS CHATTERING)

HAMILTON: He says no one bothered to tell dolphins they couldn't use tools.

SHUMAKER: They're really, really remarkable and to me what's so interesting about dolphins is they have nothing to hold tools with except their mouth and yet they are still innovative and creative.

HAMILTON: Shumaker says dolphin play with just about any object they find. But in this context, the objects are just toys. Something becomes a tool when it's used to manipulate another object or creature for a specific purpose. Jodie Baker is in charge of marine mammals. She says a dolphin named Kimo often manipulates people with a tool: a buoy.

JODIE BAKER: While we were talking, Kimo was coming over here with it. I was wondering if he was going to throw it out. Typically, if you walk by the pool and there's a dolphin playing with a toy, they'll typically throw it in your direction to get your attention.

HAMILTON: That's a form of tool use known as baiting or enticing. But Shumaker says scientists have collected lots of other examples.

SHUMAKER: One, is a dolphin that found a piece of tile, broken tile, and took it down to the bottom of their pool and used it to scrape algae off the bottom of the pool and then they ate the algae.

HAMILTON: Shumaker says you can also see tool use in wild dolphins, including some in Australia that flush out their prey with a sponge.

SHUMAKER: They hold the sponge on their rostrum, and then they use that as they disturb the sandy bottom to get fish like flounder that are down in the sand.

HAMILTON: One of the most widespread myths about tool use is that it is a sign of intelligence. Shumaker says some really smart animals do use tools, but so do creatures like the bolas spider, which hunts with a weapon made from same silk it uses to spin a web.

SHUMAKER: And when an insect flies by, they throw it and it attaches to the insect because it's sticky and they reel them in. It's very complex. Very impressive. Very dramatic. But all available information tells us that it's completely controlled from this animal's genetic history.

HAMILTON: It's programmed behavior, not something the spider figured out. Genetic programming is also the reason hermit crabs carry around another creature's shell and ant-lions throw sand at their prey. Shumaker says at the other end of spectrum are highly intelligent animals that rarely use tools.

SHUMAKER: We're standing in front of this really lovely troop of ring tailed lemurs.

HAMILTON: These lemurs are not only smart, they have fingers and opposable thumbs.

You'd expect that they'd be pretty good tool users, or pretty notable tool users and, in fact, they're not.

When intelligent animals do use tools, though, they often do so in very creative ways.

(SOUNDBITE OF ELEPHANT TRUMPETING)

TIM LITTIG: So we are overlooking the main elephant exhibit.

HAMILTON: Tim Littig is a senior elephant trainer.

LITTIG: This is Kubwa, 35-year-old Kubwa, and our latest baby, her latest calf, little Kalina who's approaching about seven weeks of age now.

HAMILTON: Kalina has been able to nurse without any help, but Littig says things were trickier with Kubwa's previous baby.

LITTIG: Her last calf was a little smaller than this one and required a stepstool to be able to reach her mammary glands to nurse. And Kubwa would move the stool around so the calf could stand up on the stool to nurse - to reach to nurse.

HAMILTON: Shumaker says this sort of creative problem solving with tools is sign of intelligence. So is figuring out how to make a tool, a skill many scientists once thought of as uniquely human. Shumaker says those scientists must not have spent much time around orangutans.

(SOUNDBITE OF ORANGUTANS)

SHUMAKER: You do have to not go up too closely because they can reach out pretty far and they'll take your equipment.

HAMILTON: Of course they would.

SHUMAKER: And your wallet.

HAMILTON: Right, yeah.

(SOUNDBITE OF LAUGHTER)

HAMILTON: Several of the zoo's orangutans make it clear they'd like to have the microphone I'm carrying. Shumaker tells a female named Knobi that she can touch it.

SHUMAKER: Nice, soft microphone cover on that. But you cannot have the whole thing.

HAMILTON: When I move beyond her reach, Knobi fetches a small tree branch.

SHUMAKER: You're seeing Knobi right now. There's some tool manufacture. She's making a reaching tool to try and get your microphone.

HAMILTON: Knobi breaks off one fork of the branch so it will fit through the mesh around the enclosure. But the branch still isn't long enough, and she's determined.

SHUMAKER: Not too surprising, she now has a much bigger, stronger tool to come get the microphone. So she's gotten a full branch now.

HAMILTON: And this reaching tool gets the job done.

SHUMAKER: So there you go. So, she's doing her best to draw the mic in.

Knobi, we're not - I'm sorry you cannot have it. Good job with your tool. Thank you for that the - thank you for that.

We've got to publish that. Oh, wow. Now she's gone and got a much bigger, stronger branch. So we're going to leave now.

HAMILTON: Just 10 or 15 years ago, scientists were still debating whether orangutans in the wild also made tools. Now it's clear they do. And so do other species. New Caledonian crows make hooks out of twigs to catch prey. Wild chimpanzees make wooden spears for hunting.

Shumaker says the most surprising and controversial findings in the new book involve so-called symbolic tools.

SHUMAKER: These are examples where we see tools being used to represent something else, or to provide a change in psychological state.

HAMILTON: One simple symbolic tool that we use all the time is money. And some monkeys and apes in captivity have learned to use tokens for a similar purpose.

But Shumaker is more intrigued by symbolic tools that can affect emotions. There are lots of examples in people. Children often have a special stuffed animal or blanket that is much more than a toy. The object represents comfort or security to them, and they use it to feel better. And in the past few years, Shumaker says, scientists have been collecting evidence that some animals use symbolic tools in much the same way.

SHUMAKER: We would see great apes in times of great stress or sadness, like a female who had an infant that died, where that female would create something that researchers called a doll, and then treated it exactly as she had treated her infant that had recently died.

HAMILTON: Scientists are still debating the significance of examples like this. But Shumaker says the fact that such a debate is even taking place shows how much things have changed since the 1960s. That's when scientists first realized that humans weren't the only creatures using tools.

Jon Hamilton, NPR News.

WERTHEIMER: You can see a crafty crow bend a piece of wire into a hook and a persistent monkey cracking open a nut using a large rock as a hammer. Find those and a few more at NPR.org.

(SOUNDBITE OF MUSIC)

WERTHEIMER: This is MORNING EDITION from NPR News. Transcript provided by NPR, Copyright NPR.