Are there any animals that mate for life?

[ladymuttly1.livejournal.com]

So I was reading a paranormal romance novel yesterday called "Slave to Sensation*" and the male hero is an Alpha Leopard who is the leader of his pack, has made a treaty with the wolves, protects the younger members, runs a construction business and is an all around okay guy. When I got to the point where I realized that Lucas was a leopard I found myself cursing. LEOPARDS don't run packs. They don't mate for life. They don't seem to have alphas. AAARGH. 

I blame Laurell. Before Laurell decided wereleopards were sexy and turned them into people with fur and with no discernible relationship to a real leopard I don't remember authors blatantly ignoring the characteristics of the animal. Now it seems that paranormal authors have decided that weres are people with fur. Am I wrong? Have I become hypersensitive thanks to the badness that is LKH?

Also-since most authors seem to be too lazy to find animals that do take just one mate I thought we could help them out. Swans are commonly thought to be monogamous. Are there any other animals out there?