Play forms an important part of a polar bear cub’s day—and who better to play with than a sibling? Polar bear play is a joy to watch and helps cubs developed needed strength and skills. It’s also a sign of the polar bear’s intelligence, which scientists believe is equal to that of the great apes.

But for these two cubs, it’s all in fun, as one invites the other to a play session.

These cubs will remain with their mother for two and a half years old. They still drink their mother’s rich milk but increasingly feed on seals, sharing kills with their mothers and learning to hunt on their own and survive in the harsh conditions of the Arctic.