Makings of an Alpha: Parasite in Grey Wolves Triggers Risk-Taking Behavior, Study Shows

According to a study, a particular parasite found in grey wolves causes risk-taking behavior, which is a key attribute of an alpha.

A fascinating explanation for why some grey wolves may be more likely to become pack leaders has been found by researchers who are studying Yellowstone National Park grey wolf populations.

Toxoplasma Gondii

According to a recent study, grey wolves exposed to Toxoplasma gondii, the parasite that causes toxoplasmosis, are more likely to become pack leaders as compared to uninfected wolves.

Toxoplasma gondii infection and risk-taking behaviors were studied using data on behavior and distribution from 1995 to 2020, blood samples from 229 anesthetized wolves, and statistical analysis. They discovered links between high-risk behaviors in both genders, male as well as female, and parasite infection.

The results showed that T. gondii-positive wolves were 11 times more likely to leave their pack. They are more than 46 times more inclined to become a pack leader than non-infected wolves. Males who had the parasite were 50% more likely to abandon their pack within six months, but if unaffected, the time frame increased to 21 months. Females showed a 25% chance of abandoning their pack within 30 months if they were infected, and a 48-month chance if they weren't.

The researchers found that while T. gondii infection frequently has no detrimental effects on the athletic ability of healthy individuals, it can be potentially lethal to young or immunosuppressed wolves. According to Connor Meyer, a University of Montana wildlife biology Ph.D. candidate and one of the study's authors, they do not yet understand how this parasite affects variables like survival rates, Science reports.

Risky Behaviors and Increased Boldness

The researchers claimed that the findings are the first to show how parasite infection affects the species' judgment and behavior.

The authors speculate that similar mechanisms may be responsible for the risky behaviors seen in grey wolves that tested positive for the parasite. Previous studies have linked T. gondii infection to increased boldness observed in hyenas and also increased testosterone production seen in rats.

The researchers discovered that wolves were more likely to have T. gondii infections in areas where there were more cougars than in areas where there were fewer cougars, which may indicate that wolves may contract the parasite through direct contact with cougars and their environments. The parasite is known to live on cougars in Yellowstone National Park.

Kira Cassidy, one of the authors, explained that the findings describe the interactions between species and this entire ecosystem. Cassidy is a research associate for Yellowstone National Park as well as its associated nonprofit, Yellowstone Forever.

Infected pack leaders may take their packs into more dangerous areas where cougars are present, potentially raising the risk of infection for uninfected wolves, according to the researchers' hypotheses, which suggested that the infection would have broader effects on the wolf population.

Meyer noted that the study, which is only the second of its kind to examine how a toxoplasmosis infection can impact a species of predators, is a potent illustration of the kinds of questions that sustained investigation can resolve.

Cassidy added that in many locations, it can be very challenging to approach a research question from an ecosystem perspective, but Yellowstone is one of these locations where we can still see all of the species that lived there hundreds of years ago.

Grey Wolves

In the 1940s, grey wolves were extensively eliminated from the western US; however, in recent decades, populations have started to recover. Some claim that the increase is harmful to people because wolves can spread disease over great distances. Wolves may also play a big role in the extinction of big game herds and the slaughter of livestock.

An interim ban on wolf hunting and trapping was imposed earlier this month by a federal judge in Montana near the Yellowstone and Glacier National Parks.

However, wolves typically exercise caution around humans. According to Cassidy, of all the large mammals found in Yellowstone, the grey wolves are the most reserved and wary, ABC News reports.

The study by Meyers, Cassidy and several colleagues was published in Communications Biology