Puckering their lips, scientists reveal whether other animals actually kiss.

Kissing is a significant aspect of human culture. According to ancient cuneiform tablets discovered in Iraq, humans have been kissing since at least 2500 BC. Today, people around the world kiss in various forms, whether as romantic gestures or friendly greetings. But do other animals kiss? Scientists have provided an answer, as reported by Live Science.

To find the answer to this question, it is essential to define what a kiss is—unfortunately, this is not straightforward. From tongue kisses to platonic pecks on the cheek, the physical expression of a human kiss can vary widely.

According to Cheryl Kirshenbaum, author of "The Science of Kissing: What Our Lips Are Telling Us," there are numerous behaviors in the animal kingdom that we might classify as "kissing": turtles touching heads; moose and gophers rubbing noses.

When studying such animal behaviors, scientists strive to avoid anthropomorphizing and interpreting animal actions through the lens of human motives and behaviors. For this reason, these actions are often referred to as "kiss-like behaviors" rather than "kisses," and they do not always carry the same positive connotation as human kisses.

A striking example is giraffes intertwining their necks and touching each other with their mouths and lips. While this behavior could be interpreted as kissing, it is actually just a ritual of dominance, not a display of affection.

According to Vanessa Woods, a research scientist in evolutionary anthropology at Duke University, primates are the only animals capable of "kissing" by puckering their lips in the same way humans do. Other species simply lack the necessary anatomy. Researchers also note that bonobos (Pan paniscus) may be among the most prolific kissers. Notably, alongside chimpanzees, bonobos are our closest living relatives.

Observations show that female-led social groups of bonobos typically resolve conflicts through sex rather than violence, unlike other primates. Scientists have also found that certain bonobo behaviors often culminate in prolonged actions resembling kissing, which occur during food exchanges and grooming. According to Woods, since bonobos tend to groom each other and share food with close companions, kisses can be seen as a "barometer of relationships" for bonobos.

In 2024, Adriano Oameira, an associate professor of psychology at the University of Warwick in the UK, suggested that the prevalence of kiss-like behavior in primates likely indicates that it represents the "origins of the human kiss." At that time, researchers stated that the human kiss is, in fact, an evolutionary remnant of grooming behavior.

However, Woods is not entirely convinced that this is the sole evolutionary reason for kissing. She believes that shared feeding is also a crucial motivator for mouth-to-mouth contact among bonobos, and that kisses may have originated from that behavior as well.

Thus, the evolutionary origins of kissing remain a mystery, but one thing is clear: while other animals may exhibit kiss-like behaviors in form or function, the full spectrum of human kissing distinguishes people from the rest of the animal kingdom.