Animal Saudi gambler backs in error (7)
I believe the answer is:
giraffe
'animal' is the definition.
(I know that giraffe is a type of animal)
'saudi gambler backs in error' is the wordplay.
'backs' suggests the final letters (I've seen 'back' mean this).
'in' means one lot of letters goes inside another.
'error' becomes 'gaffe' (gaffe is a kind of error).
The final letters of 'saudi gambler' are 'ir'.
'ir' placed within 'gaffe' is 'GIRAFFE'.
(Other definitions for giraffe that I've seen before include "The tallest animal with long neck" , "Long-necked animal" , "Tallest beast" , "African native ruminating" , "that's beastly" .)