That Bastard London was Full of Crazy Talk

Just turned the space heater to “on.” There's no point in arguing about it. It’s too cold. I had to take action, and quickly. My other option was to cut open the dog and crawl inside his carcass, but that’s been done to death and is most definitely passé.

Update: According to Outside Magazine (Feb 1995), no animal makes a practical shelter from the cold:

Other lore has suggested crawling into a bigger creature -- an elk or buffalo or whatever's handy -- but it's just not practical. Getting inside an animal is a lot of work. Soaked with the beast's body fluids, you'd become hypothermic in minutes. And in the 60-below weather that London was describing, even a big animal would freeze fast, so the benefits would be short-lived.

So, space heater it is.