Sticking Metal to Leather

What can I use to stick metal to leather? I'm hoping to customise a dog collar and have these lovely little pewter howling wolves that I want to stick to it but have NO idea how to go about it and what will make them stick...and stay stuck!

If the back side is flat, a superglue gel might work. I have used it patching chewed up leashes back together. There is a common brand of contact cement sold here called GOO that works well on many things. I have had good luck with constructive adhesive on many things. Epoxy might work too.

I would have said Superglue.....

Thanks guys. The guy at the local DIY shop recommended Araldite so I've got some of that for now. Will trial it out on an old belt before I start work on the collar!