How Smart Are Planet's Apes? 7 Intelligence Milestones

[Kristin Moore]

How Smart Are Planet's Apes? 7 Intelligence Milestones


Apes Found to Use Tools

Photograph by Michael Nichols, National Geographic

The supersmart chimpanzees of the new movieRise of the Planet of the Apes may exist only on the silver screen—but in real life, great apes are still brainiacs of the animal kingdom.

Evidence for ape intelligence got a major boost in the 1960s in Gombe, Tanzania, when Jane Goodall observed chimpanzees using a twig to "fish" for ants (pictured in a file photo)—the first documentation of wild chimps making and using tools. Until then, toolmaking had been considered a uniquely human ability.

Since then, scientists have discovered our closest cousins can use sign language, hunt with spears of their own making, and even beat college students in basic memory tests, among other skills.

(Related: "Chimps Shown Using Not Just a Tool but a 'Tool Kit.'")

Published August 5, 2011

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[Kristin Moore]

Ape Masters Language

Photograph from Bettmann/Corbis

Francine "Penny" Patterson (left), using American Sign Language, asks the gorilla Koko if she is hungry on May 21, 1976. Koko is responding that she is.

(Related: "Gorillas Are No Dummies, Zoo Study Shows.")

Koko, a lowland gorilla born in 1971, is currently the most language-proficient nonhuman, according to the Gorilla Foundation, which teaches ASL to gorillas.

The gorilla has a vocabulary of more than a thousand signs, understands about 2,000 words of spoken English, and initiates most conversations with people, according to the foundation's website.

Her IQ is between 70 and 95 on a human scale—100 is considered a "normal" human IQ.

"Great apes have [language] skills that are similar to small children," Thomas Breuer, an ape researcher with the Wildlife Conservation Society in the Republic of the Congo, said by email.

Published August 5, 2011

[Kristin Moore]

Ape Learns Words Like a Human

Photograph by Michael Nichols, National Geographic

Researcher Sue Savage-Rumbaugh hugs Kanzi, star pupil of the Language Research Center in Atlanta, after he scored excellent results on a language comprehension and syntax quiz.

Kanzi, born in 1980, is "the world's undisputed ape-language superstar," according to the website of the Great Ape Trust, a research facility in Iowa that studies ape language and intelligence.

That's because he was the first chimpanzee to acquire language as children do: by being exposed to it.

Kanzi is also the first ape to show receptive understanding of spoken English and excels in research using novel sentences—phrases that require the learning of specific responses, the website said.

What's more, Kanzi is a skilled stone toolmaker.

(See "Monkeys Recognize Poor Grammar.")

Published August 5, 2011

[Kristin Moore]

Ape Understands Individuality

Photograph by Michael Nichols, National Geographic

The orangutan Azy selects a symbol for "apple" after being shown a slice of apple by a researcher at the Think Tank facility at Washington, D.C.'s National Zoo in 1996.

"Not only does Azy communicate his thoughts with abstract keyboard symbols, he also demonstrates a 'theory of mind' (understanding another individual's perspective) and makes logical, thoughtful choices that show a mental flexibility some chimpanzees lack," according to National Geographic magazine.

As part of the facility's Orangutan Language Project, orangutans, rewarded with food, learn to use a symbol-based language presented on a computer monitor, according to the Think Tank website.

The zoo's "dictionary" has about 70 abstract symbols, all of which have no visual relation to the object they represent. There are seven categories of symbols: food, proper names of people, verbs, adjectives, Arabic numbers, nonfood objects, and proper names of orangutans.

(Related: "Orangutans Show Signs of Culture, Study Says.")

Published August 5, 2011

[Kristin Moore]

Ape Is First Known Wild Tool-using Gorilla

Photograph courtesy Breuer, Ndoundou-Hockemba, Fishlock et al, PLoS Biology

An adult female lowland gorilla in the Republic of the Congo's Nouabalé-Ndoki National Park uses a walking stick to gauge the water's depth in a file picture. The behavior, documented in a 2005 study in the journal PLoS Biology, was the first evidence that wild gorillas use tools.

Previously, chimpanzees, bonobos, and orangutans had all been observed using tools. But scientists had speculated that gorillas had lost such skills out of lack of necessity, according to the study. After all, gorillas, the largest of the great apes, can easily crush nuts with their teeth or smash termite mounds without needing tools.

(See pictures of Congo's lowland gorillas in National Geographic magazine.)

Overall, the walking-stick "observations suggest that the intelligence required for tool use evolved before the gorilla lineage split off from humans and the other great apes—providing further evidence that intelligence is not unique to humans," according to the synopsis of the study.

Published August 5, 2011

[Kristin Moore]

Apes Hunt Other Mammals With Tools

Photograph courtesy Frans Lanting, National Geographic

Ape researcher Jill Pruetz holds a spear made by a chimpanzee in 2007.

Pruetz, who receives funding from he National Geographic Society's Committee for Research and Exploration, was part of a team in Senegal that made the first ever scientific observations of chimpanzees making and using tools to hunt other mammals. (National Geographic News is part of the National Geographic Society.)

The researchers documented wild chimpanzees fashioning sticks into "spears" to hunt small primates called lesser bush babies (bush baby photo) no fewer than 22 times in 2007.

The apes' behavior shows "problem-solving at very high levels—like hunter-gatherers," said the Wildlife Conservation Society's Breuer, whose work has also been funded by the National Geographic Committee for Research and Exploration.

(Related: "Chimps Use 'Spears' to Hunt Mammals, Study Says.")

Published August 5, 2011

[Kristin Moore]

Ape Bests Humans at Memory Game

Photograph by Tetsuro Matsuzawa, Primate Research Institute via Kyoto/AP

The chimpanzee Ayumu begins a memory test with numerals jumbled on a touch screen in 2007.

Researchers at the Primate Research Institute in Kyoto, Japan, pitted young chimpanzees against human adults in two tests of short-term memory. Overall, the chimps won (watch ape-memory video).

That challenges the belief of many people, including a number of scientists, that "humans are superior to chimpanzees in all cognitive functions," researcher Tetsuro Matsuzawa of Kyoto University told the Associated Press in 2007.

Matsuzawa, a pioneer in studying the mental abilities of chimps, said even he was surprised.

The Wildlife Conservation Society's Breuer noted that "great apes are better in those memory tasks than humans—their memory functions in a very different way, and much faster than humans'."

(See "Monkeys Can Subtract, Study Finds.")

Published August 5, 2011

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