First-ever study shows bumble bees 'play'

The balls are colored with bright primary colors, the bumble bees probably thought they are flowers and try to stand on them to pollinate, but keep rolling backward!

“For instance, in this experiment, ball rolling never resulted in the provision of food. The bees’ nectar and pollen could be easily accessed in a separate room without ever having to interact with the balls. The bees never attempted to bite or extend their proboscis toward the balls in search of a sugary reward. Plus, most importantly, they came back to roll the ball one additional day or two different additional days even after foraging. (In nature, bees can be observed to stray away from the flowers that no longer give them a sugary reward.)”