This mouth-to-mouth greeting may look menacing, but it’s actually an invitation to a play session. Male polar bears engage in ritualized fighting matches while waiting for freeze-up. Scientists believe it’s a way for the bears to learn to size each other up in preparation for real fighting matches over females during mating season.

Some male bears hang out together for weeks while waiting for the sea ice to freeze, sparring from time to time and even napping together. These play sessions are carefully orchestrated and don’t cause harm to either bear. As soon as the ice forms, the bond breaks and the bears head their separate ways to hunt seals.