KITTENMauricioLima:Getty

Scientific American checks in on the world's most popular pet:

Considering that small cats do little obvious harm, people probably did not mind their company. They might have even encouraged the cats to stick around when they saw them dispatching mice and snakes. Cats may have held other appeal, too. Some experts speculate that wildcats just so happened to possess features that might have preadapted them to developing a relationship with people. In particular, these cats have “cute” featureslarge eyes, a snub face and a high, round forehead, among othersthat are known to elicit nurturing from humans. In all likelihood, then, some people took kittens home simply because they found them adorable and tamed them, giving cats a first foothold at the human hearth.

(Photo: A kitten rests near an Iraqi soldier outside a farm house while US soldiers from the 3rd Battalion, 187th Infantry Regiment (not seen) question its owner about suspected activities in the area, during a joint military patrol in Sadr Al-Yusufiyah, just south of Baghdad, on May 13, 2008. By Mauricio Lima/AFP/Getty Images.)

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