The Zombies heat status

[Cabbage Patch]

Yes, of course they have a heat signature because they are infected (not walking dead).

Excellent point!

In the "Puppet Masters" movie, where humans are being taken over by alien invaders, we discover that the controlled humans are "being run hot", at higher metabolic rates than non-controlled humans. There's a great scene after that where you see a thermal image of a group of controlled humans surround one who isn't, their images being bright red, hers being a cooler red in the core, lighter colors toward the extremities. They grab her, an alien takes control, then suddenly her heat image intensifies to match the others.