The Platypus is semi-aquatic, it lives in a burrow it digs at the edge of the river. Platypuses (or Platypi, both are correct) are solitary animals but are not agressive. They swim very well and they use the beak to detect weak electric fields generated by their prey - worms, shrimps and other small creatures of the rivers. This is called electroreception, and that's how the Platypus can find its meal even when the meal is burried in the river bottom. It then uses the beak to dig out the shrimp or worm and eats it.