India, Jan. 24 -- If the Earth's history were squeezed into a single hour, cats would stroll in only during the last five seconds. They arrived late on the evolutionary stage, when seas were rising and falling, and land bridges briefly stitched continents together before severing them again. Early cat ancestors, specialised meat-eaters, rushed into the niche this churn created. As continents joined and split, populations were split and evolved into new species: lions on African savannahs, pumas in the Americas and fishing cats in Asian wetlands. Because this evolutionary burst was short and intense, all cats still look like close relatives.

Most of these relatives want nothing to do with water. The fishing cat is the misfit. Built for mu...