Oh, on the mammoth thing. Obviously an ambush tactic. Phil did the right thing and said he didn't know.

I'm happy to take a shot in the dark, though.

While I'm sure they didn't have "tropical plants" in their digestive system as claimed, they could easily have eaten grass. What do Reindeer eat? They eat plenty of grass. During the coldest months, they find it under the snow, further south, or near thermally heated streams and pools (I saw plenty of green grass around some thermal pools in Iceland while the air temp was well below freezing). Mammoths are well known to have done the same. In fact, many of the "flash frozen" carcasses are believed to be from mammoths that ventured to a warm thermal for the easy pickings and fallen in the water or even soft mud.

This is mostly conjecture based on current species and fossil/frozen/preserved finds, but it isn't the impossibility the Nancy urban legend makes it out to be.