Infected wolves produce excess testosterone which has led them to behave aggressively. These usually leave their pack in search of a new one and lose their fear of combat with their peers.
A group of researchers have identified that the aggressive and unusual behavior of pack leader wolves is due to a parasite controlleras detailed in a recent publication in the journal Communications Biology.
According to analyzes of more than 200 gray wolves in Yellowstone National Park, in the United States, some of these wild animals carry a single-celled parasite called Toxoplasma gondiiwhich is altering his behavior.
The parasite and the wolf
The scientists determined that wolves infected with T. gondii were more likely to abandon their pack and were twice as likely to assert themselves as the leader of a new pack, following violent confrontations with other males.
After studying the blood of these wolves, “we identified a substantial increase in the odds of dispersal and becoming pack leader, both risk behaviors,” the authors wrote.
“These two vital behaviors represent one of the most important decisions a wolf can make throughout its life, and can have a dramatic impact on gray wolf fitness, distribution” and numbers, they added.
A parasite that is no stranger to humans
The parasite T. gondii is responsible for causing the disease known as toxoplasmosis. Although it is normally found in cats, it can also use humans as hosts.
Nevertheless, a strong immune system is usually enough to avoid suffering from the symptoms of the disease. Those with low defense systems hardly experience its effects beyond a simple flu.
Never underestimate such an infection
However, the chronic effects of T. gondii should not be underestimated. Several studies in animals such as chimpanzees, mice and hyenas, but also in people, have shown that the disease produces a excessive increase in testosterone, which implies that the guest takes a violent behavior and does not take into account the risks.
The researchers estimate that the parasite infected gray wolves following eating the feces of pumas that roamed the same area.
“This study demonstrates how community interactions can affect individual behavior and might potentially be extended to group-level decision making,” the experts concluded.
