How many brains do they have?

Answer 1

One, and it's about the size of a walnut. Actually, scientists thought for a while the stegasaurus may have had a brain-like structure in it's tail. The expansion of the spinal column in the pelvis gave rise to the incorrect idea that dinosaurs had two brains. Yes, the size of a walnut!

~Answers.com/WikiAnswers~

Answer 2

There's only one brain in human head. However, one brain comprises a lot of nerve impulses that release and transmit chemicals to different parts of the body in order to function well.