"I suggest we humans should keep our egos in check," Edward A. Wasserman of the University of Iowa said Thursday at the annual meeting of the American Association for the Advancement of Science.
Wasserman, a professor of experimental psychology, said that, like people, pigeons and baboons were able to tell which pictures showed similar items, like triangles or dots, and which showed different items.
This is the definition of a concept, he said, "and the animals passed it with flying colors."
He spoke at a symposium on "Animal Smarts," where researchers discussed the latest findings in the mental abilities of animals.
In the last 20 years there has been a major revolution in the understanding of animals, added Nicola S. Clayton, a professor of comparative cognition at the University of Cambridge in England.
Animals not only use tools, there is evidence that some of them save tools for future use, she said.
"Planning ahead was once thought to be unique to humans," Clayton said. "We now know that's not true."
For example, she said, crows have been seen stashing food away for the next day and even finding ways to protect it from being stolen.
The term "birdbrain," is obsolete, she said, and should be replaced by "brainy birds."
Speaking of crow intelligence, Alex Kacelnik, a professor of behavioral ecology at the University of Oxford in England, noted the "master tool user of the avian world," the New Caledonian crow.
These birds have been shown to not just use tools, but to make their own by twisting and bending pieces of wire to fish food from places they couldn't reach otherwise.
"What we are describing about the abilities of different species is that human abilities are expressed, sometimes, in other species," Kacelnik said.
Jessica Cantlon of Duke University noted that "number sense" seems among the shared evolution of many primates.
Cantlon and Elizabeth Brannon have studied how human adults and babies, lemurs and monkeys think about numbers without using language.
After seeing the same number of objects repeatedly in different-looking groups, infants notice when the number of objects is changed, they found. So, too, do macaques.
Indeed, college students and macaques seem equally able to roughly sum up sets of objects without actually counting them.
That abiliity can be useful to the macaques in determining whether there is enough food to remain in an area or to get a sense of how large their group is compared to competing groups.
They are currently working to see if monkeys can recognize the concept of zero.
Some people may be uneasy as new studies find increasing similarities between animal and human mental abilities, Wasserman said.
The aim is to learn how much thinking ability is general throughout the animal kingdom, he said, "the evidence that we collect constantly surprises us."