Large African antelope (5)
(Other definitions for bongo that I've seen before include "Rare African antelope" , "Small drum played with hands" , "Drum between the knees" , "Type of drum - central African antelope" , "One of a pair of drums" .)
'large african antelope' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for eland that I've seen before include "Browser" , "Spiral-horn antelope" , "game animal" , "Ruminant" , "Large African antelope with spiral horns" .)
(Other definitions for hartebeest that I've seen before include "African native" , "wild animal" , "Creature" , "antelope" , "Game" .)