Jan. 13, 2006 — The murky evolutionary history of cats is finally becoming clearer, say genetic researchers, who report that part of the fog has been created by cats evolving remarkably quickly, leaving behind few fossils and doing a lot of continent hopping.

Using DNA data from all 37 living feline species, an international team of researchers reported in the Jan. 6 issue of Science that they traced the cat family tree back to Asia 11 million years ago.

In that time, the ancestors of all the living groups of cats — house cats, pumas, lynxes, leopards, panthers, caracals and bay cats — emigrated between continents no less than ten times to get to their current home niches on every continent except Australia and Antarctica (not counting imported Aussie house cats, of course).

"This is a group of animals that is extremely poorly represented in the fossil record," said paleontologist Lars Wedelin, curator and feline specialist at the Swedish Museum of Natural History.

The reason, he said, is that many cats live in forested areas where bones don't tend to last long. "It's one of those cases where the genetics come first and the paleontologists are going to have to follow."

What geneticists have found is a pattern of dispersal that suggests ancestors of modern cats probably used land bridges created by climate-related low sea level stands to cross into the Americas from Asia.

Then, the cats crossed from North America to South America when volcanoes rose up and connected the two continents just three million years ago.

One of the things that has made the history even more complicated is that there appears to have been several backward migrations, with cheetahs moving from North America all the way to Africa, for instance, and pumas from South America back to North America.

This new history was constructed, in part, by matching the rates of change in genes between cat species — a sort of genetic clock — to known climate changes and geological events over the last 11 million years.

By combining the two histories, the researchers have been able to make educated guesses at when various cats moved from continent to continent.

"I think what's driving (cat) evolution is opportunity," said geneticist Stephen O'Brien of the National Cancer Institute, one of the authors of the Science report.

The need for food, room and the opening up of new lands via land bridges all provided opportunities for the cats to move into new places and adapt to new environments.

A prime example is the ocelot. Before the Isthmus of Panama emerged, there were no cats or any other large predators in South America.

When ocelot cats finally got in about three million years ago, they rapidly evolved into seven new species — the ocelot, margay, Andean mountain cat, Pampas cat, Geoffrey's cat, Kodkod and Tigrina — and took over.