Some dumb animals are pretty smart

By Gary Raham
Nature Writer and Illustrator

As humans we pride ourselves on being tops in the brains department on planet Earth. Sure, some animals can run faster, hear or smell more acutely, flash more impressive teeth and so forth, but we humans have a puffed up, convoluted lump of gray matter on the end of our spinal column that composes sonnets, builds cities and fills out crossword puzzles.

All true, but a few animals show some amazing brainpower of their own-- not only our close relatives the chimps, but also creatures as diverse and alien as dolphins, crows and parrots.

Chimpanzees can learn sign language, have been observed to fish termites out of their nests with sticks, pass on such traditions to their offspring, solve fairly sophisticated puzzles (especially when food is involved) and display complex social relationships that include an awareness of deep loss when a companion dies. In one way, it's no wonder they have such skills because they share fully 98 percent of the genetic code written in our DNA. In fact, how could a 2 percent difference in genetic instructions make such a profound difference between KoKo the chimp and Albert Einstein?

This past August, scientists reported a significant difference between humans and chimps in a nucleotide segment called the Human Accelerated Region 1 or HAR1. This little 118-"letter" segment of DNA shows only a two-letter difference between chimpanzees and chickens, for example, which are distantly related to each other. It indicates that this segment has shown little evolutionary change in tens of millions of years at least. However, between humans and chimps, separated by about five million years of evolution, 18 letters differ in the same segment.

HAR1 contains two overlapping genes, HAR1F and HAR1R. Both of these genes become active during the development of the cerebral cortex--the portion of primate brains that deal with matters intellectual. The human cortex twists, turns and expands during development much more than that of a chimp, perhaps under the direction of these genes.

But you don't have to be a primate to be smart. People have recognized the intelligence of certain whales on an anecdotal basis at least since the days of the Greek philosophers, and through detailed scientific studies on dolphins and other cetaceans since the 1960s.

Like primates, the seat of intelligence for dolphins lies in the cortex of the brain, but the organization of the cortex is significantly different. For one thing, primate brains devote large parts of their neural real estate to visual sensory input, while dolphins concentrate on sound. But the dolphin cortex looks similar in terms of the complexity of its twists and turns, and the ratio of brain weight to body weight is only slightly larger for humans when the dolphin's extra supply of insulating fat is factored out.

Dolphins show their smarts in several ways: They engage in complex play behavior and do well on problem-solving tasks. The work of Karen Pryor in the late '60s showed that dolphins demonstrated real creativity by being able to learn that to get a food reward they had to perform a sequence of new behaviors of their own choosing. In a control experiment, it took humans about the same length of time to figure out the same learning task. Dolphins will also wrap pieces of sponge around their snouts to keep from bruising them - a demonstration of tool use - and they communicate with a complex mixture of clicks and whistles, including "signature whistles" that represent the names of different individuals in a social group. A study published in 2000 claims the bottle-nosed dolphin displays behavior consistent with self-awareness because it can successfully use a mirror to investigate certain marked portions of its body.

But it may be that crows, ravens and other birds in the family Corvidae demonstrate the most alien brand of high intelligence from a human point of view. They prove that "bird brains" can be quite effective in the smarts department. Ravens, for example, can solve difficult puzzles like untangling a knotted string to free up a treat, or they can steal fish by hauling in an untended fisherman's line. Crows on the island of New Caledonia have learned to use twigs to spear grubs from beneath rotting logs. In the mid 1800s, the Rev. Henry Ward Beecher once said, "If men had wings and bore black feathers, few of them would be clever enough to be crows."

Although the brain-to-body-weight ratio of crows is larger than that for dolphins and nearly matches that of humans, those brains have relatively wimpy cortical development. In the 1960s, neurologist Stanley Cobb discovered that corvid intelligence originates in a brain structure called the hyperstriatum rather than the cortex.

"The larger the hyperstriatum, the better birds fare on intelligence tests," said Candice Savage in her book, "Bird Brains" (Sierra Club Books, 1995). Crows, ravens and magpies all fall at the high end of hyperstriatum development. Their large brains "are packed tight with exceptionally large numbers of brain cells."

Another researcher, Irene Pepperberg at the University of Arizona, has worked with African gray parrots - most successfully with one named Alex. Alex can identify more than a hundred objects by name and understands the concepts of same and different, absence, quantity and size. Pepperberg claims that Alex has mastered tasks once thought to be the province of only humans or certain nonhuman primates.

So, it appears that we humans should not let our swelled heads swell our heads. In "The Hitchhiker's Guide to the Galaxy," science fiction writer Douglas Adams said, "For instance, on the planet Earth, man had always assumed that he was more intelligent than dolphins because he had achieved so much--the wheel, New York, wars and so on - whilst all the dolphins had ever done was muck about in the water having a good time. But conversely, the dolphins had always believed that they were far more intelligent than man--for precisely the same reasons."