Newborn rabbits compete for their mother's milk, but when the temperature drops, that competitive spirit gives way to cooperation:
LinkUsing infrared cameras (right) and rooms that slowly cool from 23°C to 11°C, researchers found that when the temperature drops, less-than-5-day-old furless rabbit pups huddle to share heat.
Such cooperation, like investors making a joint business venture, comes at a small private cost, as generating heat uses body fat that in turn uses up oxygen, and using too much oxygen can stunt a rabbit's growth.
But by sharing heat, rabbits mutually ensure that their siblings don't have to use up too much energy to survive the cold, helping them all live on to contribute to future bunny generations.