Whether you're a cat person or dog person — or you're truly enlightened and reject that false dichotomy, as you know in your heart of hearts that all pets are precious — you've probably wondered how our furry friends evolved from lions to house cats, from wolves to chihuahuas. So have zoologists, a great many of whom have published papers attempting to unravel this mystery. Though there's no universally agreed-upon consensus, a number of takeaways have emerged from this work.
Dogs have been man's best friend for thousands of years, but their ancestors weren't quite as friendly. It's impossible to know precisely when and how that changed, but scientists have nailed down some key details — namely, that canines did indeed descend from a now-extinct wolf species anywhere between 15,000 and 40,000 years ago and that their relationship with humans changed forever.
There's disagreement about where this happened, and different theories posit that our four-legged besties first came into existence everywhere from China to Europe. Krishna R. Veeramah, a professor in the Department of Evolution and Ecology at Stony Brook University, said in a 2017 study that "there was likely only a single domestication event for the dogs observed in the fossil record from the Stone Age and that we also see and live with today.”

So what was that event? Well … no one knows for sure. Some think that people simply captured wolves as pups, raised them as pets, and this process gradually resulted in the dogs we know and love today; others believe that several different groups of people domesticated dogs independently of one another at different times, which could help explain why there are so many different breeds found all over the world.
Moving past the when and where, which will likely continue to be a matter of debate for some time, we arrive at the how. One increasingly popular theory suggests that "survival of the fittest" was replaced with "survival of the friendliest" — which is to say, the wolves that stopped competing with humans for food and instead worked with them gained favor.
It makes sense when you think about it — wolves are aggressive creatures when they need to be, and anyone attempting to deliberately tame them is likely to have an extremely difficult time. Genetic evidence supports the theory, as does the case of Russia's domesticated foxes. This would also account for how adorable dogs have become: If friendlier-looking wolves were fed by people and thrived as a result, those traits would then be passed on to their puppies, grandpuppies, and so on and so forth until you end up with huskies and golden retrievers and all kinds of puppy-dog-eyed canines.

In that sense, their story might not be so different from that of cats. It will come as little surprise to anyone who "owns" (read: tends to) a feline that they probably domesticated themselves. Their DNA is a 95.6 percent match with that of tigers, but as far back as 9,500 years ago in Cyprus, where the earliest known house-cat remains were discovered, they too diverged from their genetic ancestors.
It's widely believed that some cats were captured by farmers to hunt rodents, and the next step is so cat-like it's hard not to laugh: Cats enjoyed the food, shelter, and other privileges of their new station so much that they decided to stick around and keep enjoying said benefits in exchange for doing something they'd be doing anyway.
Adding to the humor is the fact that, as suggested by Smithsonian archaeologist Melinda Zeder and others, cats might not be entirely domesticated. Think about it: They're happy to ignore you when they aren't hungry, they know their own names but choose not to answer when called, and even the most loving cats are known to scratch and/or bite their humans for no apparent reason. It's possible that a few thousand more years of domestication will change this, but honestly, we hope not.
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