Applying Earth science to science-fiction scenarios might not be easy (or particularly necessary) but it sure is fun. Here, fans take the cutting-open-a-furry-beast-and-using-its-carcass-as-an-emergency-blanket scene from The Empire Strikes Back and attempt to deduce how long Luke Skywalker could have actually survived on the sweet, sweet warmth provided by Tauntaun entrails.
In a normal environment, a carcass gets cold in 8 to 36 hours losing an average rate of 1.6 degrees Fahrenheit per hour. However, the ice world of Hoth is not an average environment. The Star Wars database lists that Hoth reaches nightly temperatures of -60 F. In a frigid, sub-zero environment, body heat can be lost almost 32 times faster. This means a Tauntaun's body heat could drop almost 51.2 F every hour.
The initial estimate is probably off, as it looks like the author is using human body temperatures to figure how warm the Tauntaun would be when it died and how fast it would lose heat, but some of those issues get hashed out in the comments.
Wolf Gnards blog: How Long Could Luke Survive in a Tauntaun?