GabyKissing is an essential part of human culture. Ancient cuneiform tablets discovered in Iraq reveal that people have been kissing since at least 2500 B.C. Today, we actively exchange kisses of various kinds—romantic, familial, or friendly. But do animals engage in similar behaviors? In the animal kingdom, there are numerous displays that resemble kissing. Variations on the human kiss can range from a passionate kiss with tongues to a platonic peck on the cheek. The intention behind a kiss on the lips can also vary. For instance, pressing your lips against someone else’s during CPR may resemble a romantic kiss, but no one considers it as such. Cheryl Kirshenbaum, author of *The Science of Kissing: What Our Lips Are Telling Us* (Grand Central Publishing, 2011), explains that in the animal world, there are many behaviors that could be considered kisses—from turtles touching heads to moose rubbing noses.
Perhaps one of the most obvious examples of animal kissing is licking. Researchers studying these actions strive to avoid anthropomorphizing them, refraining from interpreting them through the lens of human motives. Thus, these behaviors are often referred to as “kiss-like behaviors” rather than “kisses.” They don’t always carry the same positive connotation as human kisses. For example, in the African savanna, you might observe a pair of giraffes intertwining their necks and occasionally touching each other with their muzzles and lips. However, this kiss-like behavior is not an expression of affection; it is a dominance ritual that giraffes use to establish higher and lower status.
What about primates? Primates are the only animals that can kiss using extended, folded lips, much like humans do. Among the biggest kiss enthusiasts are bonobos (*Pan paniscus*). Along with chimpanzees (*Pan troglodytes*), they are our closest living relatives. Vanessa Woods, an evolutionary anthropology researcher at Duke University, told *Live Science* that female-led social groups of bonobos resolve conflicts through sex rather than violence, as many other primates do. Although bonobos don’t necessarily kiss during sexual encounters, something akin to kissing can be observed when these primates share food and groom each other. According to Woods, kisses can be seen as a barometer of relationships for bonobos.
In a 2024 article, Adriano Lameira, a psychology professor at the University of Warwick, suggested that human kissing may actually be an evolutionary remnant of mutual grooming behavior. During this grooming, primates extend their lips and suck on their partner’s skin to remove insects or debris, which resembles kissing.
Meanwhile, Woods is not entirely convinced that this is the only evolutionary reason for kissing. She believes that sharing food is also a significant motivator for mouth-to-mouth contact among bonobos. While the evolutionary origins of kissing remain a mystery, one thing is clear: animals also exhibit behaviors that resemble kissing. However, the wide range of human kisses sets us apart from the rest of the animal kingdom.
