Rhino calf running.

With white rhinos, the calf always runs in front of the mother, and with black rhinos, it runs behind the mother.

This is a survival tactict due to their differing habitats: White rhino, being grazers (grass eaters) prefer open savannahs where there's lots of grass.  And lots of room. Lions, their main predator, prefer attacking running prey from behind, and they always target the stragglers. The habitat being open with room to run, the mother covers the rear in order to protect her calf.

Black rhinos on the other hand, are browsers, eating leaves and twigs. Therefore they prefer dense thickets with lots of shrubs and trees. No room to simply run. So the mother would take the lead, bulldozing an escape route for her calf.