Know your small mammals in Jackson Hole? What’s this guy?

This little guy was hanging out on my bird feeder, chowing down on some sunflower seeds the other day. He looked like a weasel but I knew he had a different name. My friend thought surely it was stoat (aka ermine) but I know for a fact that stoat turn white in the winter and are half the size of this guy. He could have been some sort of ferret, but certainly wasn’t a short-tailed or long-tailed guy since he was much bigger and had a fuller tail. His yellow belly is what finally gave him away. Know what he is?

He eventually figured out that it was easier to hold on to the cage. Smart guy.

Then he decided it was more convenient to just lay on the ledge and eat. So what is he?

A Pine Marten who apparently LOVES sunflower seeds.