A mind-controlling parasite that affects hyenas - and humans too

Surely you know someone who feels better the closer they get to a risky situation.

In this gallery, we will tell you the case of a group of hyenas who suddenly began behaving differently from the usual. It wasn't because they felt like it, but because they were under the control of a parasite in their bodies.

(Photo: Chuttersnap / Unsplash)

A study published in the scientific journal Nature Communications suggests that the offspring of hyenas infected with Toxoplasma gondii move dangerously close to lions. The ones who are not sick, keep a safe distance.

(Photo: Zdenek Machacek / Unsplash)

The data were collected in decades-long observations of these animals in the Masai Mara National Reserve in Kenya.

While healthy hyenas went only within 300 feet of the lions, the sick ones dared to go up to 50 meters and, of course, their chances of dying were four times greater.

Ecologist Kay Holekamp, co-author of the aforementioned survey, acknowledged to the National Geographic website that she was surprised by something that was at the same time "incredibly evident."

Although hyenas are natural predators, in the first years of life they are protected from other animals by adult hyenas. They are not hunting, but without supervision, they might roam too close to more dangerous species.

And then there's this striking fact about toxoplasma and human beings. The single-celled protozoan has been found in 1/3 of the human population.

(Photo: Ryoji Iwata / Unsplash)

There are reports that this parasite has led infected people to be more reckless, even causing traffic accidents. On the other hand, this "encouraging" effect has also had good consequences for some.

(Photo: Laura Gariglio / Unsplash)

Proof of this is a study published in the National Center for Biotechnology Information (USA) which shows that people with toxoplasmosis have a greater probability to develop entrepreneurial activities than others who do not have the disease.

(Photo: Humphrey Muleba / Unsplash)

Although most people who suffer from toxoplasmosis, an illness caused by toxoplasma, have flu-like symptoms, the illness in pregnancy can cause malformations in the foetus.

(Photo: Taylor Wright / Unsplash)

In fact, it is recommended that pregnant women avoid contact with cat feces or urine. That's because felines are the ultimate hosts of toxoplasma. It is in their bodies that this parasite reproduces.

(Photo: Mel Elias / Unsplash)

Toxoplasma also manipulates infected rodents to act risky among domestic cats.

(Photo: Alexandr Gusev / Unsplash)

Infected animals lose their aversion to the smell of their predators' urine and, as a consequence, they lack any fear of approaching them.

This effect may have occurred in the hyena pups from the study we cited. In any case, the survivors seemed to have learned, over time, about the danger of provoking a lion. They've started to do it less and less.

(Photo: Bhargava Srivari / Unsplash)

“It is a parasite that people think is mostly benign, especially in humans, but when we look at some of these effects, Toxo can have major impacts on human behavior, including at the social level,” researcher Stefanie Johnson explains to National Geographic.

(Photo: Matthew Henry / Unsplash)