This work, published Wednesday in the journal iScience, could provide valuable assistance in the face of urban expansion, which is forcing some animals to gather in reserves.

"I've always loved lions," Jessica Burkhart, neuroscientist and lead author of the study, told AFP.

After studying the brains of these animals in the laboratory, she wanted to observe them in real life.

While cats have a reputation for being independent, lions buck that trend.

They live in groups, and gain and defend territories in the African savannah.

"Male lions, for example, leave their group when they are a few years old, meet other males they don't know (...), with whom they will bond for life," he said. she explains.

This kind of behavior indicates that lions -- unlike leopard or cheetah loners -- are biologically hardwired to be social in certain situations.

Which made it an interesting animal to test for oxytocin.

- Greater tolerance -

Oxytocin strengthens social bonds.

It appears in a mother's brain looking at her newborn baby's eyes, causing a feeling of happiness and well-being.

Some therapists even suggest that couples facing marital problems look into each other's eyes to release oxytocin.

Similar effects have been observed in other species, for example between humans and their dogs.

Jessica Burkhart and her colleagues worked in Dinokeng Game Reserve in South Africa, using pieces of meat to bait lions.

The hormone had to be sprayed directly on their noses, using what looked like an old perfume bottle, in order to reach the brain directly.

The 23 lions who received the treatment were found to be more tolerant of other lions in their space, especially when in possession of a desirable object.

"Once the lions received oxytocin, they were given their favorite toy, and we saw the distance (between them and their conspecifics) reduced from 7 meters without treatment, to 3.5 meters with it", detailed Jessica Burkhart.

Treated lions also no longer roared back to listening to recordings of intruder roars -- unlike lions that received no treatment, or others that had only been sprayed with saline solution.

A fear

This reduced aggression towards foreign lions is particularly encouraging, according to the researcher, because oxytocin is also known to have a perverse effect in humans: if it provokes positive feelings towards close people, it can also increase rivalries. to outsiders.

According to Jessica Burkhart, this treatment could be useful in several scenarios.

First, it could help lions rescued from circuses or zoos in war zones, and then placed in sanctuaries.

In addition, lions face a growing problem: cities are expanding and encroaching more and more on their territory.

Defenders of animals must thus transport them to reserves, where groups who do not know each other are forced to rub shoulders.

Oxytocin could help prevent conflicts here.

Finally, the treatment could also help when the lions are returned to the wild, so that they adapt better to their new social environment, making them "more curious and less fearful", according to Ms Burkhart.

But the treatment also raises a fear that unscrupulous people -- in the vein of zoo officials portrayed in the documentary series "In the Kingdom of the Wild" -- will use it to allow visitors to pet animals.

A practice much criticized by associations.

"There are indeed corrupt people. But we can hope that oxytocin will help more than it will cause damage", wishes the researcher.

© 2022 AFP