Koko the gorilla can comprehend roughly 2,000 words of spoken English. She doesn't have a vocal tract suitable for responding verbally, so the 40-year-old ape signs her thoughts using a modified form of American Sign Language. Counting her native gorilla tongue, she is, therefore, trilingual.
And she doesn't just talk about food. Over the 28 years that gorilla researcher Penny Patterson has worked with Koko, the ape has expressed a whole range of emotions associated with humans, Patterson says, including happiness, sadness, love, grief and embarrassment.
Alex the African grey parrot could utter some 150 English words by the time of his death in 2007. The wordy bird demonstrated that he could count up to six objects, distinguish between numerous colors and shapes, combine words to create new meanings and understand abstract relational concepts such as "bigger," "smaller," "over" and "under." On the night of his death, at age 31, Alex's last words to his handler, animal psychologist Irene Pepperberg, reportedly were: "You be good. See you tomorrow. I love you."
From Chaser the border collie and Kanzi the bonobo to Akeakamai the dolphin, lab animals of many stripes have excelled at learning the rudiments of human languages. But despite the great strides these animals have made in crossing the species divide and communicating with humans in human terms, people have seldom ventured the other way.
Surely, as the most intelligent species, humans could learn to understand dolphin-speak better than dolphins learn sign language. Instead of trying to teach human communication systems to animals, why don't people decode theirs?
As it turns out, many scientists are trying. They hope to someday learn dolphin, elephant, gorilla, dog and all the other animal tongues. One scientist has already decoded a great deal of prairie dog. But researchers are off to a slow and late start down this road, because they're having to overcome a major obstacle of their own making: the idea that animals don't actually have languages.
"It's a hotly debated area, because there are still people who want to separate humans from other animals," said Marc Bekoff, professor emeritus of ecology and evolutionary biology at the University of Colorado, Boulder, and co-founder (with primatologist Jane Goodall) of Ethologists for the Ethical Treatment of Animals. "So if you're doing fieldwork and you see something in the animal's communication system that looks like syntax, they're going to say it isn't." [ 6 Amazing Videos of Animal Morality ]
Prairie dog prattle
Constantine Slobodchikoff may have ventured further beyond this barrier than anyone. A professor emeritus of biology at Northern Arizona University, he has spent decades decoding the communication system of Gunnison's prairie dogs, a species native to the Four Corners region of the U.S. Southwest. Prairie dogs are rodents. They aren't particularly renowned for their smarts. And yet, in dozens of books and articles over the past three decades, Slobodchikoff and his colleagues have laid out extensive evidence that prairie dogs have a complex language. And he can understand a lot of it.
When they see a predator, prairie dogs warn one another using high-pitched chirps. To the untrained ear, these chirps may all sound the same, but they aren’t. Slobodchikoff calls the alarm calls a "Rosetta stone" in decoding prairie-dog language, because they occur in a context people can understand, enabling interpretation.
In his research, Slobodchikoff records the alarm calls and subsequent escape behaviors of prairie dogs in response to approaching predators. Then, when no predator is present, he plays back these recorded alarm calls and films the prairie dogs' escape responses. If the escape responses to the playback match those when the predator was present, this suggests meaningful information is encoded in the calls.
And indeed, there seems to be. Slobodchikoff has discovered the rodents have distinct calls pertaining to different potential predator species, such as coyotes, humans or domestic dogs. Their calls even specify the color, size and shape of the predator; for example, they'll differentiate between an overweight, tall human wearing a blue T-shirt and a thin, short human wearing green. [ Video: Prairie Dog Alarm Calls ]