This story is seriously fascinating...recommend the full read, it's only a little over twice as long as the quote:
A study of 26 years' worth of wolf behavioral data, and an analysis of the blood of 229 wolves, has shown that infection with the parasite Toxoplasma gondii makes wolves 46 times more likely to become a pack leader.
The research shows that the effects of this parasite in the wild have been horrendously understudied – and its role in ecosystems and animal behavior underestimated.
If you have a cat, you've probably heard of this parasite before. The microscopic organism can only sexually reproduce in the bodies of felines, but it can infect and thrive in pretty much all warm-blooded animals.
This includes humans, where it can cause a typically symptomless (but still potentially fatal) parasitic disease called toxoplasmosis.
Once it's in another host, individual T. gondii parasites needs to find a way to get their offspring back inside a cat if it doesn't want to become an evolutionary dead-end. And it has a kind of creepy way of maximizing its chances.
Animals such as rats infected with the parasite start taking more risks, and in some cases actually become fatally attracted to the scent of feline urine, and thus more likely to be killed by them.
For larger animals, such as chimpanzees, it means an increased risk of a run-in with a larger cat, such as a leopard. Hyenas infected with T. gondii also are more likely to be killed by lions.
Something Strange Happens to Wolves Infected by Infamous Mind-Altering Parasite
A study of 26 years' worth of wolf behavioral data, and an analysis of the blood of 229 wolves, has shown that infection with the parasite Toxoplasma gondii makes wolves 46 times more likely to become a pack leader.
www.sciencealert.com