This parasite manipulates wolves, mice, and possibly your mind

what makes wolf Will they launch attacks alone or claim swarm leadership? This question has long intrigued scientists.Now, new research shows gray wolves are infected with parasites toxoplasma gondii They are more likely to be top dogs than uninfected wolves.

The findings call for thinking more broadly about what influences animal behavior, study co-authors said. Kira Cassidywildlife biologist Yellowstone Wolf Projecta Montana-based non-profit organization that oversees research on American predators. yellowstone national park.

“We know that behavior is influenced by all sorts of factors, including past experience, genetics, current circumstances, and social background,” she says. “Now we can add parasites to that list.”

toxoplasma gondii is a single-celled parasite At least one-third of the world’s population is infected Any time with toxoplasmosis disease. Infection is usually mild, but can be fatal in young and immunosuppressed people. toxoplasma Although it can only multiply in the gut of domestic or wild cats, it is ubiquitous in nature and can infect any warm-blooded animal. They are also noted for their ability to manipulate their hosts, making rodents reckless, especially around house cats. (read how toxoplasma Affects the human brain. )

A new study recently published communication biology, Cassidy and colleagues utilized 26 years of behavioral data and blood samples from Yellowstone wolves dating back to 1995, when dogs were reintroduced to the park.They also analyzed the spatial distribution of cougars in the park and blood samples of big cats, known toxoplasma host.

As a result, wolves living in overlapping territories with cougars toxoplasma Than a wolf without a cat neighbor.

Additionally, wolves that tested positive for parasites were 11 times more likely than uninfected wolves to disperse from the pack and more than 46 times more likely to become pack leaders.

These findings aren’t all that surprising Gregory Milnean epidemiologist at the Royal Veterinary College in London, was not involved in the study.

“This is very consistent with what we know. cough in other animals,” he says. “There is increasing evidence that this parasite can cause meaningful behavioral changes.”

fatal charm

Ann animals can be infected toxoplasma Eating another infected animal or coming into contact with the parasite’s egg-like cysts in cat feces.

Once parasites inhabit a host other than cats, they can colonize various areas of the body, including the brain, where they can persist for years. Because parasites need to reach a cat’s gut in order to reproduce, they’ve evolved clever ways to make that happen. (Get facts about parasites and why they matter.)

For example, parasite-infected rodents become more active and less fearful around predators such as domestic cats, delivering the parasites to their preferred homes. toxoplasmaInfected mice and rats even lost their fear of the smell of cat urine, attracted by the smell.

Many of the findings in rodents have come from carefully controlled laboratory studies, and only recently have researchers begun investigating their effects. toxoplasma Infection in the wild.

In one study, infected chimpanzee toxoplasma They are attracted to the urine of leopards, their natural predators.In another study, researchers showed that they were infected Spotted hyena cubs approach lions and are more likely to be killedaccording to study co-authors just lowan evolutionary biologist at Nova Southeastern University in Florida. (Read how toxoplasmosis is harming endangered seals in Hawaii.)

“We’re just beginning to scratch the surface of how behavioral impact affects. cough Known in rodents, identified in wildlife, and now found in highly social animals such as hyenas and wolves, infections affect the dynamics and behavior of groups that impact ecosystems.” he says.

risky business

Evidence is accumulating that people with toxoplasmosis are at greater risk than people who are not infected. more dangerous drivingoften lead to traffic fatalities.

However, the impact is not always negative. In one survey of college students and business professionals, infected with toxoplasma You are more likely to major in business or start your own business. Countries with high infection rates were also less likely to cite fear of failure as a reason to undertake new entrepreneurial activities.

It is not known exactly how a distant relative of malaria, the parasite, causes such changes in mammals. (Learn more about parasites that mind control their hosts.)

Milne says there is some evidence that parasites can affect neurotransmitters such as dopamine and hormones such as testosterone. It is also possible to give

Whatever the mechanism, parasites, especially toxoplasma — play an important and underappreciated role in animal life.Scientists are approximately 40% of animal species are parasitesand they are probably Most species yet to be discovered.

“Many more behaviors can be affected by this parasite than the average person would guess,” says Gering.