Hot Cocoa

Why is it after a snow shovelling, toboganning, skate outside or almost any winter activity do we get a craving for a nice hot cocoa?
I don't remember my first cup of cocoa but I do remember the first time I craved it after a day out in the cold. In grade school we went out to the local park/forest to look at animal tracks in the snow. I really enjoyed it because it was a park that I went to with my friends and I got to notice things that I hadn't seen before. It was through a teacher that came to our school on occasion to teach us about the outdoors. It was through Mr Nasimoks (or something like that) eyes that we saw things. We ended the day back near the school but still outside. He had a giant thermos full of what was a very watery hot chocolate but it warmed me through and through. It was shortly after this that we got to go out again but this time we went cross country skiing. Old skis, no real winter gear like today besides some long-johns and a pair of mits that once wet were worse than having nothing on at all but it was fun. At the end of the day we were back outside the school as cold as ever and I craved that hot chocolate ( I say chocolate because it's water based and I think hot cocoa has to be made with milk). I was not disappointed as the giant thermos was there again and I filled up with the warmth that I come to expect after any outdoor winter outing.

I think we have passed this on to our kids as we can't go out in the winter without a request for cocoa when we get back home. Sometimes we have to bring it with us as we can't make it home without the warm chocolatey goodness.
I wonder if those that are in tropical regions have a similar drink that they crave when coming in from the heat? Hot Cocoa seems to be universal in the cold regions of the world but I'm not aware of a universal cold drink for the hot regions. Maybe the Icecap fits the bill.

Update:
Link to a page about Mr Nasimok