Climbing the Cat's Tree

The "kitty kat" is, by far, one of my son's favorite animals. But whence come our fluffy, fickle friends (evolutionarily, that is)? And their larger, less cuddly cousins like the puma or lion, for that matter?

A team of researchers at the National Cancer Institute may have put the question to rest (or at least given it a cat nap). After analyzing DNA from all 37 living cat species, the team has constructed a family tree for the family Felidae, rooted in a single species living in Asia 11 million years ago. From there, the cats spread across the world in at least 10 intercontinental migrations, with changes in sea level giving evolution a nudge. (See the original abstract in the journal Science.)

Building the cat family tree has been a perplexing problem, as dated cat fossils are few and far between and many of the modern cat species diverged very recently. The research team got around these issues by using information from the sex (X and Y) chromosomes and mitochondrial DNA (often used for calibrating evolutionary clocks) to measure how related different species of cat are and when the different branches on the evolutionary tree split off from each other.

So where does this put the "kitty kat?" The household cat is the youngest member of the family, emerging 6.2 to 6.7 million years ago, with domestication probably occurring within the last several thousand years (the oldest known pet cat was found two years ago in a 9,500 year-old burial site in Cyprus). The team plans to next investigate the time and location of the cat's domestication.

Additional links:
New Scientist
Nat'l Geographic