Hippos spend the bulk of their day submerged in whatever water is nearby. The dominant male uses his tail to fling his dung as far as possible to mark the herd's territory. He patrols the bank of the river or lake where his cows and calves are lounging in the water. He splashes the water as a warning to unwelcome visitors and often charges with his jaws wide open, showing off his flesh-tearing tusks.