Friday, January 06, 2006

It pays to be a parasite: The cat

I've half-jokingly praised the parasitic brilliance of the dog. Arguably, however, dogs are symbiotes. We gave them our garbage, they cleaned the premises. Physically weak humans could ally with physically strong dogs, given evolution more playgrounds to tweak the mind.

Domestic cats, on the other hand, are pure[1] parasites:
DNA Offers New Insight Concerning Cat Evolution - New York Times

With each migration, evolutionary forces morphed the pantherlike patriarch of all cats into a rainbow of species, from ocelots and lynxes to leopards, lions and the lineage that led to the most successful cat of all, even though it has mostly forsaken its predatory heritage: the cat that has induced people to pay for its board and lodging in return for frugal displays of affection.
How did evolution shape the cat, so it was so able to prey so effectively upon human weaknesses? One clue (also from this week's NYT Science) is that human's are programmed to respond to anything resembling a helpless infant. Cats appear to have evolved to take advantage of that weak point.

One can only speculate on the alliance that evolution might build between cats and toxoplasma. It would make sense that toxoplasma, a rapidly evolving parasite, could alter the behavior of both cats and humans to further its own agenda ...

I do love ecology.

[1] Ok, so they killed rats, mice and other "vermin". Sigh. Guess they were symbiotes once too ...

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