One live cat, one dead rat, and one plush toy parasite (available from giantmicrobes.com)
The Cat has caught five rats in five days: either she's a very skilled huntress, or the rodents who pass through my back garden are absolutely useless at keeping out of harm's way.
Alternatively, they could be infected with the parasite Toxoplasma gondii which seems to cause them to lose their innate fear of cats and, indeed, become amorously aroused when they smell cat urine, rather than run and hide.
This may sound like a joke, but it's true: researchers at Stanford University discovered that the brains of infected male rats show heightened activity in the region associated with sexual response and various emotional states. In other words, the parasite deliberately manipulates the romantic behaviour of male rats in order to increase the chance that they'll be eaten by a cat.
Why would it want to do that? Because T. gondii can only reproduce inside the cat's small intestine, so it's vital - if it wishes to complete its lifecycle - that it find a way into its definitive host's digestive system.
As one of the scientists in the research team said, it's very impressive: for there are not many protozoan organisms that can fuck with the heads of other (more complex) species in this manner. It might even be argued that T. gondii knows more about the neurobiology of fear and attraction and epigenetic remodelling than we do.
Afternote
Once T. gondii has reproduced inside the cat's gut, the parasites are excreted in faeces; which is how shit-eating rats become infected, though they can infect any warm-blooded animal, including human beings. In fact, it may interest readers to know that approximately 30-50 per cent of the world's human population is believed to be infected with T. gondii (in France, this figure rises to over 80 per cent).
Fortunately, for most people, infection causes no ill effects, but it can be fatal for those with compromised immune systems and there are also recent studies showing that there may be a possible link with schizophrenia. So, perhaps these parasites are playing with our brains too, which, actually, aren't all that different in terms of circuitry and neural processes from those of rats.
Fortunately, for most people, infection causes no ill effects, but it can be fatal for those with compromised immune systems and there are also recent studies showing that there may be a possible link with schizophrenia. So, perhaps these parasites are playing with our brains too, which, actually, aren't all that different in terms of circuitry and neural processes from those of rats.
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