That's a "gnu"!
Kudu
Oribi is a small African antelope
eland
kudu
Oribi
Impala
gnu
dik-diks Dikdik
dik dik
eland
The dik-dik is a small African antelope that lives for months with no water except for dew and the moisture in its diet of vegetation.
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.