As long as I am credited for any of my work used, I'm OK with that. Most of my animal mods are resources anyway. It's just courteous to ask, just to be sure, if nothing else - I don't often say no, even if it's for other games.
Those are indeed my textures that I worked on for many hours. I'd recognise them anywhere! If you're trying to claim these as your own, then shame on you. If you didn't get permission (and I certainly don't remember you) then shame on you again.
I don't mind you using them, but do the right thing and ask first, and credit me for the original work at least. Don't claim it as your own. That's the lowest of the low thing to do.