Northern white-cheeked gibbon 
Northwestern Wolf 
Nubian Giraffe 
Nubian ibex 
Numbat 
Nyala 
Ocelot 
Ochre bush squirrel 
Okapi 
Olinguito 
Olive baboon 
Olympic marmot 
Onager 
Oribi 
Oriental small-clawed otter 
Ornate cuscus 
Ornate titi 
Ozark big-eared bat 
Pacific white-sided dolphin 
Palawan stink badger 
Pale fork-marked lemur 
Pallass cat 
Pallass Long-Tongued Bat 
Pallass Squirrel