HomeOutdoorsNews‘Mind-Controlling’ Parasite Is Affecting Wolf Behavior in Yellowstone National Park

‘Mind-Controlling’ Parasite Is Affecting Wolf Behavior in Yellowstone National Park

by Lauren Boisvert
(Photo by William Campbell/Sygma via Getty Images)

A new study of Yellowstone National Park wolves shows that wolves infected with a particular parasite may be more likely to strike out on their own or become the leader of their pack. This study essentially could change the way we look at animal behavior, says co-author and wildlife biologist with the Yellowstone Wolf Project Kira Cassidy.

“We know that behavior is influenced by all sorts of factors, including past experiences, genetics, current circumstances, and social context,” she told National Geographic. “Now we can add parasites to that list.”

The parasite in question is Toxoplasma gondii, which causes the disease toxoplasmosis. It infects at least one-third of the human population at any given time, according to National Geographic. It is usually a mild infection. People usually recover without treatment, but medication can ease symptoms. However, the disease posed much more risk to very young children and those who are immunocompromised.

The parasite can only reproduce in the intestinal tract of domestic or wild cats. But, it does run rampant in nature. It affects any warm-blooded animal, such as the wolves of Yellowstone, and is known for its ability to manipulate its hosts. It almost has a “mind control” aspect to it, most notably making rodents act recklessly around cats, according to NatGeo.

New Study of Yellowstone Wolves Claims Parasite May Make Them More Willing to Go Solo or Take Leadership Roles

The study was recently published in Communications Biology. Kira Cassidy and her team went back 26 years to when wolves were reintroduced to Yellowstone National Park in 1995. They drew on behavioral data and blood samples for their study. They also studied areas where cougars roamed the park and blood samples from the big cats. Cougars are known as prominent Toxoplasma hosts in the wild.

What the study found was that wolves whose territory overlapped with the cougars’ territory were more likely to be infected with Toxoplasma than wolves who didn’t cross paths with the cats.

Additionally, infected wolves were 11 times more likely to leave their pack and go solo. They were also 46 times more likely to take on leadership roles in the pack than uninfected wolves.

“It’s quite consistent with what we know about Toxo in other animals,” says Gregory Milne, an epidemiologist at the Royal Veterinary College in London. He was not involved in the study, but commented, “It adds to the growing body of evidence that this parasite can cause meaningful behavior changes.”

Non-feline hosts may become infected by eating infected prey or through contact with cat feces. The parasite can take up residence in other parts of the body in non-feline hosts, like the brain. In animals like rodents, the parasite actually makes them more reckless around cats. Then the parasite can be delivered to its ideal host: the cat.