Extraterrestrial adaptation

Robert Sapolsky

If an alien creature invaded earth by entering the brain of human beings, hijacking their nervous system and driving them to engage in high-risk ventures sure to lower their chances of survival .. you’d think some of us might notice something. Yet something disturbingly like this may be happening without notice. When mice get infected with toxoplasmosis, an alien bacterium, the toxoplasmum goes dormant inside the amygdala of their brain and reduces their fear of cats [link]. Cats eat the reckless mice and ingest the toxoplasmas where they wind up in the intestine mingling with others of their kind. Toxoplasmas reproduce sexually only in the gut of the cat, so suppressing the fear response in rats and mice is a sure way of gaining entrance into the cat intestine. Neuro-practitioners call this ‘adaptation by behavioral manipulation’ [link]. A parasite learns to manipulate host behaviors that enhance their own chances of survival. In other words, these alien bacteria learn to perform brain surgery in order to get rides to wild parties where they can exchange DNA and procreate!

Apparently these clever little creatures have found their way into people too. Nearly one third of all humans have dormant toxoplasmas sleeping inside their amygdala. Since people are pretty high up in the food chain ..the only real threat comes from themselves (or perhaps an unsuspecting bear or mountain lion). Chances are, infected individuals will start acting recklessly and wind up getting killed in a car accident involving excessive speed. So they only appear in the traffic section of the paper, or the actuarial tables of an insurance company. Otherwise, symptoms appear close enough to schizophrenia that they wind up in a psychiatric population and are never heard from again. I think I would call this a successful alien predation.