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Genetically Engineered Mouse is Not Scared of Cats
Gary writes "A team from the University of Tokyo has genetically engineered a mouse that does not fear cats. By tweaking genes to disable certain functions of the olfactory bulb (the area of the brain that receives information about smells directly from olfactory receptors in the nose) the researchers were able to create a 'fearless' mouse that does not try to flee when it smells cats, foxes and other predators. 'The research suggests that the mechanism by which mammals determine whether or not to fear another animal they smell -- and whether or not to flee -- is not a higher-order cerebral function. Instead, that decision is made based on a lower-order function that is hardwired into the neural circuitry of the olfactory bulb.'"
http://news.nationalgeographic.com/news/2007/04/070403-cats-rats.html
"The parasite Toxoplasma gondii uses a remarkable trick to spread from rodents to cats: It alters the brains of infected rats and mice so that they become attracted to--rather than repelled by--the scent of their predators. "
...toxoplasmosis does the same thing to mice.
In a fascinating infectious lifecycle, a mouse with toxoplasmosis is eaten by a cat, which then harbors the responsible parasite in its intestinal tract. The feline's feces is now infected, and the next mouse to come in contact with it is now infected as well. This mouse now loses his innate fear of cats, which virtually guarantees that he'll be eaten. Lather, rinse, repeat!
-R