Researcher in the desert

A young researcher goes to the sahara in hopes of a great discovery.
He finds a desert flee and he says to him "Jump."
The flee jumps.
He tears out one of its legs and says again "Jump."
The flee jumps again.
This goes on until the flee has no legs.
Then the researcher says one last time "Jump."
The flee does not jump.
The researcher writes his findings into his notebook:
"If you tear out all the legs of a desert flee, it will go deaf."