WASHINGTON - Animals are a lot smarter than most people realize.
In a flurry of recent books and research papers, scientists report that some animals can perform simple arithmetic, form mental maps of their environment and understand bits of human language. They also can exchange elaborate messages with each other, master intricate social relationships, create tools and teach others to use them.
A few animal whiz kids even demonstrate a rudimentary self-awareness and can handle abstract concepts - such as whether things are the same or different - intellectual capacities previously thought to be limited to people.
"We share the planet with thinking animals," said Marc Hauser, a neuroscientist at Harvard University. "Insights from evolutionary theory and cognitive science have begun to revolutionize our understanding of animal minds," Hauser writes in his new book, "Wild Minds."
The brainiest are chimpanzees, which share 99 percent of our DNA and can be taught an elementary form of human language. Next come talking birds, whose ability to make intelligible sounds opens a window into the nonhuman brain that no other species provides.
Many other species, including dolphins, whales, elephants and crows, also exhibit intelligent behavior but have not been studied as intensively as apes and talking birds.
Irene Pepperberg, a biologist at the University of Arizona in Tucson, has trained a parrot named Alex to name, request or refuse more than 100 objects. She said Alex now understands such abstract concepts as "same," "color" and "how many?"
Pepperberg calls Alex an "avian Einstein." Alex knows his numbers up to six, she says.
Scientists acknowledge that there is an enormous gulf between human and animal mental capacities, and animal researchers compare their subjects to human babies - not to adults.
In her book "Minds of Their Own," Australian animal psychologist Lesley Rogers says a baby's developing brain forms "maps of the infant's own body and the world around it. Animals do likewise. Neurophysiologists have found such maps laid out in the cortex [the outer layer of gray matter over most of the brain] of cats and monkeys."
In a report in the January issue of the Journal of Experimental Psychology, Columbia University researchers Elizabeth Brannon and Herbert Terrace describe how three monkeys were trained to understand the sequence of numbers from one to nine.
