Gregory Robinson
Scientists have uncovered the shocking relationship between wolves and a parasite that can also infect humans.
Wolves live in packs that are led by a breeding pair. Although some wolves stay with their pack, which operates like a family unit, helping out with hunting and raising pups, others may choose to find a mate elsewhere and start their own packs.
Numerous factors could explain why a wolf may split or assert leadership of a pack, such as their particular personality and family relationships. It’s a question that has long baffled scientists.
However, new scientific findings have just unearthed a surprising influence a parasite known as Toxoplasma gondii has on gray wolves and their behaviour.
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Scientists found that grey wolves in Yellowstone National Park who were infected were more likely to leave the group they were born into or become a pack leader.
Toxoplasma gondii is a single-celled parasite that causes a disease called toxoplasmosis, which can also infect humans and affects over a third of the global population at any given time.
Although the infection is usually mild, it can be dangerous or even fatal for infants and people with weakened immune systems.
Toxoplasma gondii reproduces only in the intestines of domestic and wild cats, however, it can infect any warm-blooded animal. It’s especially well-known for altering the behaviour of its host, famously making rodents less scared of, you guessed it, cats.
An animal can get Toxoplasma by eating another infected animal or by coming into contact with the parasite’s eggs found in cat poop.
If the parasite ends up in an animal that’s not a cat, it can settle in places like the brain and stay there for years.
So, what does this mean for humans?
Growing evidence suggests that people with toxoplasmosis take more risks than those who are uninfected, such as dangerous driving.
As part of a new study, published in Communications Biology, co-author and wildlife biologist with the Yellowstone Wolf project Kira Cassidy and colleagues analysed 26 years of behavioural data and blood samples collected from Yellowstone wolves.
The research team also looked at where cougars were in the park and tested their blood, since cougars are known to carry Toxoplasma.
Wolves that lived near cougars were more likely to have Toxoplasma.
Even more surprisingly, infected wolves were 11 times more likely to leave their pack and over 46 times more likely to become a pack leader compared to wolves that weren’t infected.