A team from the Australian University of Murdoch has found that in deep waters, shark whales, the largest known fish, circulate at tremendous speed. The information has been obtained following the movement of eight whale sharks, pasting in the fin an instrument they invented for it. Until now the fish were not considered to be fast because they move very slowly on the surface of the water. However, it seems that they take advantage of the great weight of being the biggest fish to go deep: they sink with the force of gravity, almost without spending energy. This system is very useful both for hunting and moving from one side to the other, as they reach a great speed.