What's the internal body temperature of a Tonton?

What's the internal body temperature of a Tonton?
Lukewarm.

This is a pun. This joke also requires the hearer to understand a bit of pop culture to make sense of it. A Tonton is a beast that Han Solo (in the original Star Wars trilogy) rode on while out hunting for his friend Luke. Luke was found freezing to death, and Han sliced open the Tonton and shoved Luke inside of it to warm him up.

So, the joke here is that the inside of a Tonton is Luke-warm (warm as Luke is), and also lukewarm (not that warm). This is not really that good of a joke.