By BBC News Online's Matt McGrath A parasitic infection in some rats alters their natural behaviour and makes them easy prey for cats, research shows. It ensures its return to its favourite host by affecting the brains of the normally cautious rats, making them outgoing and active and an easy meal for a hungry cat. Dr Manuel Berdoy, and colleagues, report their work in the Proceedings of the Royal Society.
Rats can usually detect subtle changes in their environment.
It makes them very hard to trap or poison but this parasite overrides the innate response - they almost taunt the cats in a sense. In rats, the infection is usually contracted from eating cat faeces. The parasite then works itself into every organ in the rat's body especially the brain where it forms dormant cysts. There it remains viable for the lifetime of the rat, waiting for a cat to come along and eat the rodent so that it can spring to life again. Dr Webster has been studying the effects of this parasite for years.