Smaller dolphins sometimes leap vertically. Common dolphins play with one another in a somewhat rough fashion, rushing towards one another. The favorite activity of the common dolphin, however, is bow-riding. They ride off ships and the pressure waves created by whales. They may stay with the vessel, jumping and playing, for a period of up to several hours.
Common dolphins are also a very affectionate species.
They care for their sick by using their fins to keep the ailing dolphin afloat so it may breathe. Moreover, they make friends with the members of their groups and show obvious emotions towards them. In captivity, two males who were separated became very excited when reunited. Also when members of the group are separated or die, dolphins exhibit emotions of sadness and seem to be pining away for their playmates. Within the groups, adults act as teachers to the young.