Do Polar Bears Kiss?

A 2026 Ig Nobel Prize went to scientists who redefined what counts as a kiss. Under this new definition, polar bears apparently kiss too.

The Ig Nobel Prizes celebrate research that, in the organisers’ words, first makes people laugh and then think. This year’s awards were presented on September 3 in Zurich, Switzerland, with prizes recognising research on everything from buried underwear to cockroach milk.

The 2026 Biomechanics Prize went to a group of researchers for their work on the phenomenon of kissing. Their study examines kissing from an evolutionary perspective. While its main comparative analysis focuses on primates, the research also has implications for other animal species.

What counts as a kiss?

That question becomes less straightforward once humans are removed from the equation. A recent review of mammalian close-contact behaviour explains that kissing itself has traditionally been defined as lip-to-lip contact. According to the review, under this concept, kissing has been recorded only in humans, chimpanzees and bonobos.

The Ig Nobel-winning researchers took a broader approach. Looking for a definition that was not centred on humans and could be applied across species, they defined kissing as non-aggressive, deliberate mouth-to-mouth contact between members of the same species, involving some movement of the lips or mouthparts and no transfer of food.

Under this definition, the animal kingdom suddenly has more kissers. Among the non-human animals explicitly mentioned by the authors are polar bears. As one example, the study cites a YouTube video titled French kissing polar bears, showing two captive polar bears engaged in prolonged, apparently non-aggressive mouth-to-mouth contact. Research and observations specifically on kissing in polar bears, however, appear to be limited.

Other close encounters

For such powerful predators, known for highly aggressive behaviour towards other animals and even cannibalism, polar bears can also engage in remarkably gentle, non-aggressive physical contact. Mothers frequently touch and groom their cubs, which can sleep cradled on their bodies. During courtship, as a male and female become accustomed to one another, polar bears also engage in non-aggressive touching, and breeding pairs have been observed walking together and lying near one another in the snow.

Another interesting form of close interaction, although not a kiss even under the new definition, is the nose-to-nose greeting. In general, nose-to-nose contact is widespread among mammals, including species that are normally solitary, and can have different meanings and functions. Polar Bears International describes nose-to-nose greetings as a way for one polar bear to ask another for something, such as access to food. A visiting bear may approach slowly before gently touching noses with a feeding bear.

So, do polar bears kiss? Apparently yes. And they rub noses too. Whether polar bears themselves would recognise these descriptions is another matter.

Polar Journal AG Team