by According to an analysis of more than 200 gray wolves in Yellowstone National Park, wolves infected with behavior-altering parasites are more likely to become pack leaders or leave their packs altogether. The results add to a growing body of evidence to support this Toxoplasma gondiia protozoan parasite, pulls the puppet strings of its hosts and lures them into risky behavior.
“We found wolves that showed signs of this had a significant increase in the likelihood of dispersing and becoming pack leaders, both risky behaviors T. gondii Infection in her blood, the authors wrote in the study, published online Nov. 24 in the journal communication biology (opens in new tab).
“These two life-history behaviors represent some of the most important decisions a wolf can make in its lifetime, and can have dramatic effects on fitness, distribution, and the overall rate of births and deaths within a population,” the scientists reported.
toxoplasmosis — the disease caused by a T. gondii Infection – is everywhere. While T. gondii Because it can only reproduce sexually and complete its life cycle in felids (members of the cat family), it is perfectly at home in any warm-blooded host—including about 33% of all humans and more than 10% of the US population. A healthy immune system is usually enough to keep symptoms of the disease at bay, and people without an immune deficiency rarely experience anything more frightening than mild flu-like symptoms during an acute infection. but T. gondii can have a lasting effect; A handful of studies have found that chronic infection can lead to an increase testosterone levels and behavior changes into people.
Related: The strange tale of a larger-than-life wolf that nearly broke the law
And we are not alone. Rodents infected with the parasite produce an excess of testosterone and are less afraid of cats, Live Science previously reported. Hyenas with toxoplasmosis are more likely to wrestle African lions, according to a 2021 study published in nature communication (opens in new tab); (opens in new tab) and carry chimpanzees T. gondii are not afraid of leopards, their natural predators, scientists reported in the journal in 2016 Current Biology (opens in new tab).
Met Yellowstone’s gray wolves T. gondii migrating through the same volcanic wilderness as infected cougars (Puma concolor) and eat cat feces, the new study says. Researchers examined nearly three decades of data on wolves captured, released and monitored in Yellowstone. They discovered that infected wolves were more likely than uninfected wolves to engage in risky behaviors, such as leaving their families to form new packs, and were twice as likely to assert themselves as pack leaders, often resulting in dangerous fights with other would-be wolves resulted in top dogs.
But toxoplasmosis is not all fame, independence and power struggles. Pregnant wolves suffering from an acute infection may miss a litter, and wolves that do not fear a fight are more likely to suffer fatal injuries. The study authors also raised the possibility that infected wolves could endanger the entire pack by fearlessly leading conspecifics into cougar territory, where they could also become infected.
“This study demonstrates how community-level interactions affect individual behavior and can potentially be extended to group-level decision-making,” the authors write. “Incorporating the impact of parasitic infections into future wildlife research is critical to understanding the effects of parasites on individuals, groups, populations, and ecosystem processes.”
