Elegant and enigmatic, cats tantalize not only those of us who share our sofas with the smaller versions but scientists who have tried to puzzle out the origin and evolution of their larger cousins. Where did the modern cat family evolve? Why and when did they leave their homes and migrate across continents? How many species actually exist, and which ones are closely related?

Experts generally agree that there are 37 species in the family Felidae, but they have offered dozens of classification schemes, ordering cat species in as few as two to as many as 23 genera. Who could argue? Under the skin, one cat species appears pretty similar to another. They look like big cats, midsize cats and small cats. Distinguishing a lion’s skull from a tiger’s can be a challenge even for an expert, and genetic investigations that we have tried over the past two decades have failed to sort the cats into definitive groupings.