While we know parrots can mimic human language, studies show they actually have an understanding of that language. It also becomes difficult to compare between species since most intelligence tests or tasks are designed for specific animals. Animals evolve certain kinds of cognitive abilities to deal with pressures in their natural habitat, said Virginia Morell, author of "Animal Wise." We also tend to underestimate the brainpower of animals by relying too much on intelligence tests based on what humans are capable of. The good news is "we're getting a better idea of how animals think and experience the world," Morrell said.

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