‘Love Hormone’ Oxytocin Turns Ferocious Lions Into Friendly Cats

Lions touch their heads together in an act of bonding
Scientists found that lions exposed to oxytocin bonded with each other and showed less aggressive behavior. Hoberman Collection / Getty Images

Oxytocin, the powerful hormone that helps individuals bond with each other, can apparently turn a massive, roaring lion into a cuddly kitten, scientists have found. Sometimes called the “love hormone,” oxytocin reinforces the attachment bonds between mothers and children, romantic partners and friends, and even people and their pets.

In a study published recently, lions who had oxytocin sprayed up their noses became much more cordial with their neighbors and roared less often at lions they didn’t know, Phys.org reported. The study, “Oxytocin promotes social proximity and decreases vigilance in groups of African lions,” appeared in the journal iScience.

According to the study, administering oxytocin could have crucial benefits for conservation and the management of populations of lions in the wild, since it softens the interactions between those that are unfamiliar with each other. 

“Our study provides evidence that oxytocin administration may increase prosocial behavior between unfamiliar individuals, suggesting that oxytocin could potentially serve as a management tool to aid in introductions of lions both in captivity and in the wild,” the researchers wrote.

Increasingly, lion prides are being pushed into private reserves due to urban expansion, where they are in closer proximity to each other, reported Phys.org. Unlike cheetahs and leopards, lions are social animals, but can also be violent and protective of their territory. Those that are rescued from circuses, breeding facilities and other unhealthy circumstances are kept away from other individuals if they can’t be socialized successfully.

In situations like these, the bonding influences of oxytocin could be helpful.

“If you think about male lions, for example they will leave the pride when they’re a couple of years old and they will meet up with other male lions they don’t know and they’re not related to, and they will form lifelong bonds,” said University of Minnesota neuroscientist Jessica Burkhart, who was the lead author of the study, as Phys.org reported.

In 2018 and 2019, the researchers sprayed oxytocin up the noses of 23 lions on a wildlife reserve in South Africa. When the lions were given the hormone, they were more accepting of other lions getting closer to a toy they had been given.

“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 seven meters with no treatment to about 3.5 meters after oxytocin was administered,” Burkhart said, as reported by Phys.org.

According to Burkhart, the effects of oxytocin seem to kick in pretty quickly.

“If I spray an aggressive lion, by the seventh squirt their demeanor completely changes. They are chilling out. They are blinking a lot which lions do when they are chilling,” said Burkhart, as Smithsonian Magazine reported. “We always wait 45 minutes just to make sure it’s taking effect, but in my opinion it seems to kick in within a few minutes.”

In contrast with lions who weren’t treated with oxytocin, the lions who were didn’t respond in kind when they heard recordings of the roars of strangers, which Burkhart said was an especially good sign, reported Phys.org. In humans, oxytocin can have the effect of causing competitiveness with those who are not part of a group.

“Currently we’re working on introductions of animals who have been rescued from circuses or overseas or war zones that now live in sanctuaries,” said Burkhart, as Earth.com reported. “The hope is that this will translate to animals being relocated in the wild, helping them to become more inclined to their new social environment so they’re more curious and less fearful, leading to more successful bonding.”

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