Yea, it's really hard to tell with mixed breeds. Especially with his coloration, there are a lot of breeds combined that make that color pattern.
His coat is very short, and extremely dense, very hard to spread it to see his skin. and has very odd markings, strange,darker colored lines that run through out his coat.
Great temperament though. Very smart, catches on easily, and hard headed, but what puppy isn't?
Maybe some day I'll splurge on a DNA test to find out. I'm just one of those nerds that likes to know.