How Cats Conquered the World
When your cat leaves a mangled mouse on your pillow, he wants you to know that he’s a conqueror. In fact, he is part of a race of conquerors, the successful descendants of a winding journey in which cats made use of humans to conquer the world. Now researchers have used genetics to create the most extensive map ever made of cats’ path to worldwide domination, published this week in the journal Nature.
Modern domestic cats all descend from a single type of wild cat: Felis silvestris lybica. From archaeological studies, researchers believe that F. s. lybica’s reign begins in the Near East, in a region stretching from modern-day Turkey down to Lebanon. Around 10,000 years ago, farmers began storing grain, which attracted pesky mice. Cats, it turned out, could help out with that.
But F. s. lybica also ruled in Ancient Egypt, where they left their traces in cultural artifacts from cat mummies to statues and paintings. Researchers wanted to know: How did these two separate cat-doms lead to today's global feline success?
That wasn’t a question that could be answered with modern cat genetics alone. Around the world, the gene pools of modern cats are surprisingly similar, thanks to millennia of tagging along with human travelers and interbreeding wherever they went. “The modern domestic cats in Australia are the same as in Europe and as in America,” says Eva-Maria Geigl, paleogeneticist at the Institut Jacques Monod, CNRS and University Paris Diderot, and an author on the study.
So for this latest study, the team turned to the genetics of ancient cats around the globe to untangle their collective rise to power. By sifting through 9,000 years of genetic data, the researchers found that there were two separate waves of human-cat coexistence, with cats befriending both farmers and Vikings in their quest to spread around the globe. It also seems that over the course of this relationship, domestication happened fairly late in the game—if at all.
To collect enough samples, the researchers reached out to other scientists around the world for feline bones or teeth, whose toughness and stability make them most likely to harbor useable DNA. They ultimately analyzed over 200 ancient cat skeletons that spanned roughly 9,000 years. They also collected samples from modern cats for comparison. For each of these samples they looked at mitochondrial DNA, genetic material found in every cell that is passed on from mother to child, making it a useful tracer of evolution.