What are the smartest animals in the world and how do we know? There are many members of the animal kingdom that rival our own wits.

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No other member of the animal kingdom can ace an algebra test or write an A+ essay. But that doesn’t mean other species aren’t highly intelligent.
• Chimpanzees

On certain memory tests, chimpanzees do far better than us humans.
Chi Kingvia Flickr
Chimpanzeesare our closest living relatives. We share almost 99 percent of our DNA (the little bits of genetic code that make us who we are) with them. It turns out that they share some of our brain power as well. In a studypublished in 2007, researchers gave adult chimps, adolescent chimps, and college students the same cognitive test. The exam involved remembering where a list of numbers—from one to nine—were located on a touch screen monitor.
Chimps and humans alike saw the numbers in their locations for less than a second. Then they were asked to remember where those numbers had been and show the researchers. The adult primates and humans performed about the same. But the adolescent chimps left them both in the dust. They remembered each number’s location with far better accuracy. Researchers think that these youngsters were using a type of photographic memory, which allows an individual to recall images with extremely high accuracy even if they only glanced at them for a split second.
• Goats

A goat pulling a lever (A), lifting a lever (B), and enjoying the "fruit" of its labor (C).
Briefer et al. / Frontiers in Zoology
Scientists have thought for a long time that goats are far smarter than their unassuming demeanor leads many of us to believe. Finally, a group of researchers in Australia decided to put these barn animals  to the test...

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