Rodents a soldier's catching abroad (7)
I believe the answer is:
agoutis
'rodents' is the definition.
(I've seen this before)
'a soldier's catching abroad' is the wordplay.
'soldier's' becomes 'GI's' (term for US soldier).
'catching' is an insertion indicator.
'abroad' becomes 'out' (abroad can mean away or out).
'gis' going around 'out' is 'goutis'.
'a'+'goutis'='AGOUTIS'
(Other definitions for agoutis that I've seen before include "Rodents" , "More than one animal" .)