Lions typically aren't keen on making new friends. The giant cats guard their territory fiercely and can mortally wound a foe with a single swipe. While aggression is an advantage for apex predators in the wild, it poses real challenges for lions on reserves or in captivity, a number that is growing due to habitat loss.
Researchers working on a wildlife reserve in Dinokeng, South Africa, found that an intranasal application of the "love hormone" oxytocin could make lion meet-cutes less life-threatening. Their work appeared March 30 in the journal iScience.
In the summers of 2018 and 2019, a team led by animal biologist Craig Packer and neuroscientist Sarah Heilbronner from the University of Minnesota spent their days using hunks of raw meat to lure lions up to a fence so they could spray oxytocin up their noses with a tool that looks like an antique perfume bottle.
By spraying the oxytocin directly up the nose, it can travel up the trigeminal nerve and the olfactory nerve straight up into the brain.
After these treatments, researchers observed that the 23 lions who were given oxytocin were more tolerant of other lions in their space and displayed less vigilance towards intruders.
"You can see their features soften immediately, they go from wrinkled and aggressive to this totally calm demeanor. They totally chill out. It's amazing," said Jessica Burkhart from the Department of Ecology, Evolution and Behavior at the University of Minnesota, in a report posted on the Cell Press network.
Researchers measure social tolerance by seeing how close a lion who has possession of a desired object, in this case a pumpkin toy, will let others approach it.
"After the lions were treated with oxytocin, and we gave them their favorite pumpkin toy to play with, we saw the average distance between them drop from about 7 meters with no treatment to about 3.5 meters after oxytocin was administered,” added Burkhart.
