dik dik
eland
gnu
eland
kudu
Oribi is a small African antelope
calf (baby antelope)
Buffalo is not really an antelope, but it is the closest relative to the antelope where the name ends with an o.
A three letter African antelope is the "gnu", which ends in a "u" not a "you". The more common name for the gnu is the wildebeeste, but that won't fit into your crossword puzzle.
Ted
dik-diks Dikdik
Gnu.
Suni
Ibex