They live by feeding on the blood of humans and other warm-blooded animals.

It would seem that there are two types of warm-blooded animal.

It would soon become the greatest mass destruction of warm-blooded animals in human history.

The lesson: In the far north, if you want to be up and about with the warm-blooded animals, you've got to dress like them.

But whether they were warm-blooded animals or reptiles, he could not decide.

All those characteristics I just listed are limited to warm-blooded animals in modern times.

He also did some of the early research into bioelectricity in warm-blooded animals.

For warm-blooded animals, a lot of energy is burned just keeping our body temperature where we need it.

"And they've gotten pretty good at finding warm-blooded animals like us."

No warm-blooded animal on earth uses more energy, for its size.