Thursday, January 05, 2006

Cats did get around

New research has clarified the lineage of cats. Turns out that over millions of years they circulated in and out of Africa, Asia and North America, splitting and meeting along the way. Interestingly invaders didn't seem to wipe out indigenous cats -- in contrast to the expansion of humans.
Cat-Blogging from Deep Time. The Loom: A blog about life, past and future

...The scientists were able to reconstruct the evolutionary tree of cats with a great deal of statistical confidence. Their results are published in this week's Science (link to come). I've put the illustrations from the paper at the bottom for those who like to revel in the gorey details. What's particularly neat about the paper is that it offers a hypothesis for how cats spread around the world. The researchers came up with this hypothesis by looking at where cats are today, and then mapping their locations onto the evolutionary tree.

The common ancestor of all living cats, according to their results, lived in Asia about ten million years ago. This cat's descendants split into two branches. One led to lions, jaguars, tigers, leapards, snow leopards, and cloud leopards. The other branch gave rise to all other cats. These early cats remained in Asia until 8.5 million years ago, when new lineages moved into the New World and Africa. The New World immigrants gave rise to bobcats, couggars, lynxes, ocelots, bobcats, and other species found in the Western Hemisphere today. The African migrants were the ancestors of today's servals and other small cat species.

But cats have a way off wandering. The ancestors of domestic cats moved back from North America back into Asia around 6.5 million years ago. Lynxes moved back as well about 2 million years ago, spreading west until they reached Spain. The ancestors of today's mountain lions in the New World also produced another lineage that moved back into Asia and eventually wound up in Africa, where it became today's cheetahs. Other big cats moved into Africa at around the same time--the cousins of tigers and snow leopards in Asia moved through the Sinai peninsula and evolved into African lions. But close cousins of the lions moved into the New World, evolving into jaguars.

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