Wild kids grow up to be these (6)
I believe the answer is:
ibexes
'wild kids grow up to be these' is the definition.
(an ibex is a type of goat - kid is a young goat)
This is the entire clue.
(Other definitions for ibexes that I've seen before include "Large wild goats" , "Mountain goats with long curved horns" , "Mountain-dwellers" , "Wild mountain goats with beards" , "Large mountain goats" .)