Animal that jumps requiring a lot of space (3)
I believe the answer is:
roo
'animal that jumps' is the definition.
'a lot of space' is the wordplay.
'a lot of' means to remove the last letter (a lot of but not all of the word).
'space' becomes 'room' (enough space or room to do something).
'room' with its last letter taken away is 'ROO'.
'requiring' acts as a link.
(Other definitions for roo that I've seen before include "Jumping marsupial" , "Small inhabitant of Hundred Acre Wood" , "Kanga's child (Pooh)" , "young skipper" , "large animal" .)