300mm f2.8 (borrowed from a friend) and 1.4 tele on full sensor camera (so essentialy a 420mm lens). Yeah, we think of these critters being so white but against the true white of the snow they really do have more of a yellow tinge to them.
Those Arctic foxes are quite small. Much smaller than the Red fox. More like a really big cat I'd say. Real skitish too, but quite cute none the less. This guy did little more than open an eye while we watched him. We did see one the night before cruising around a bear. They apparently follow them because the bears eat a lot of the blubber leaving meat behind. Thus these critters get a free meal essentially.