Zoo Tycoon 2

I dunno how old this post is, but oh well. Your animals could be squeaky clean, but if the neighboring exhibit, or you have a poop collection building near by, that could be a couple reasons why. However, I've found that some animals you really can't make happy. Check to make sure you have the right biome for the animal as well. If it is a one animal exhibit (i.e. no mate or a friend) they will get lonely. Try giving them an enrichment item or two. ...And if all else fails, boot their ass to nature and see how they like the real world and get a new animal or two.

I have the answer. Try clicking on the snow leopard. Then, click on the zookeepers face. It will show all of the things that animal likes. And FYI, sometimes male animals like different things then the female animals. Like the male moose likes a scratching post but the female doesn't. If this doesnt work, try getting a new animal.