The Amateurish Naturist and the Lice

An amateurish naturist decides to study the behaviour of lice. He sets the lice on a sheet of paper and tells him:
“Lice, jump!”
And the lice jumps. Then the naturists cuts off the legs of the lice and sets it back on the sheet of paper, ordering:
“Lice, jump!”
The lice doesn’t move. The naturists then writes down in his notebook: “after cutting off the legs, the lice goes deaf.”