Fatal attraction in rats infected with Toxoplasma gondii

This classic experiment tested whether the felid parasite Toxoplasma gondii manipulates rodent behavior to favor transmission back to its definitive cat host. The authors found that infected rats lost their innate aversion to cat odor and even showed attraction to areas scented with cat urine, while their responses to other cues remained largely intact. This selective change, dubbed fatal attraction, would make infected rats easier prey, completing the parasite life cycle. The study became a foundational demonstration of host behavioral manipulation by a parasite and sparked an entire research field on Toxoplasma and neurobehavioral change. It is central to understanding the cat-rodent transmission cycle and the evolutionary logic of why a brain-dwelling cat parasite would alter prey behavior.