Mind-Altering Parasite Blinds Chimps to Imminent Danger

(Credit: imit Virdi/Shutterstock) When a chimpanzee sees a leopard, its reaction is appropriately intense and immediate: run away. Millions of years of evolution have embedded a natural fear of predators in our closest evolutionary ancestors' minds. However, a parasite found in cat feces, Toxoplasma gondii, may cause them to act irrationally bold when faced with real danger. Researchers in France and Germany examined the way chimpanzees infected with the T. gondii parasite reacted to leopard urine, and found an intriguing correlation: Those with the parasite displayed a marked lack of fear when confronted with signs of their most dangerous predator, compared with chimps free of T. gondii, who appropriately kept their distance. A link between infection and predation suggests that a similar process took place in prehistoric humans, who also counted big cats among their enemies.