One i know of is an Ant Eater .
Armadiloes, Ardvarks, Antelopes.
There is no animal that has a long o at the beginning.
Orang-utan is a type of rainforest animal that starts with an 'o' at the start of it's name.
orangatang
oven
into
Orangutang Opossum
Old English SheepdogOx
· Opossum · Otter
Juno
oats
Organization and Methods Analyst
Opossum. They're nocturnal animals and their name begins with o.