With short sudden movement snake gets rodent (6)
I believe the answer is:
jerboa
'rodent' is the definition.
(jerboa is a kind of rodent)
'with short sudden movement snake' is the wordplay.
'with' is a charade indicator (letters next to each other).
'short' means to remove the last letter.
'sudden movement' becomes 'jerk'.
'snake' becomes 'boa' (boa is a kind of snake).
'jerk' with its last letter removed is 'jer'.
'jer' next to 'boa' is 'JERBOA'.
'gets' acts as a link.
(Other definitions for jerboa that I've seen before include "Mouse-like jumping rodent - ear job (anag)" , "Desert rodent" , "Desert-dwelling rodent" .)