Pip.
pip
Could be "s'il".
oop
Try "argosy."
APO
APO
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.
Eel.
The answer to 60 down in the New York Times crossword puzzle for Feb 22, 2010 is the three letter word USE.
maybe "met"?
COB
Bambi's mate Faline. Today's Times crossword asks for a Disney doe, three letters?
If this is for a crossword puzzle, the three letter answer is "ALP". Arlsberg Pass is a mountain pass in the Austrian Alps.