How cold is cold blooded?

I’m in the middle of writing a scene where one of my iVokh characters is feeding on a rock lizard, and feeling disgruntled because it has to work so hard to drink ‘lukewarm blood’.

As I finished that sentence, I looked at what I had written and experienced a moment of doubt. I knew reptiles heated their bodies from external sources — i.e. the sun, a sun-warmed rock, warmth in the air etc — but I really didn’t know what the temperature range of their bodies truly was.

Would their blood really be cool enough to feel ‘lukewarm’?

When in doubt, Google! After a few dead ends, I finally found these amazing images :

If you click on the image you should see a larger image that clearly shows the difference in temperature between the human and lizard on the left and the lizard’s head and tail on the right. Best of all, these infra-red images show that lizards do take on the ambient temperature around them. For me, this means a rock lizard in a cave would be significantly cooler than the iVokh eating it!

I love how fiction and reality can sometimes mesh so perfectly. :)

cheers

Meeks

p.s. I strongly recommend following that link to the page itself. You will find lots more interesting pictures as well as some fascinating facts about why mammals and lizards are different.