What is this beluga doing with this piece of wood?

Play-type behaviours are widespread among cetaceans. Bottlenose dolphins are famous for playing with turtles, jellyfish and even objects. Bowhead whales have been seen in the Beaufort Sea handling a tree trunk with their pectoral and caudal fins and trying to keep it balanced on their backs.

Distinguishing between play and exploration of the object can be difficult, especially since play can be considered to be exploratory. Where does one draw the boundary? Not an easy task. It would seem, however, that exploring involves increased use of the senses such as sniffing, drinking, and touching, while playing is characterized by a greater employment of motor activities like manipulating, pulling, and pushing. Is the beluga just curious or is it playing with that stick?

Learning or compensation?

Far from simple amusement, the behaviours that we associate with playing can also fulfil an important educational function. In its interactions with the environment, the young individual develops his or her social and cognitive skills. Take for example killer whales, which are notorious for playing with their prey before devouring them. If, upon seeing a killer whale hurl a seal into the air, one might conclude that it is a cruel game, it is often a question of elaborate hunting techniques that adults are teaching to their offspring. Might the interaction of the beluga with this piece of wood represent a learning experience?

Mammal behaviour is still shrouded in mystery and coloured by human interpretation. Only through observations and long-term studies can we hope to learn more about this branch of biology that is still poorly understood.