Problem:

Warm blooded animals like us keep their temperature constant irrespective of their surroundings. But how do they do that? Energy should be supplied from the inside. I assume that reactions like making ATP from glucose are exothermic. That means in winter our body reacts more. Water is absorbed by that reaction. We should need more water in winter.

Question 1: Which is contradictory with our real life experience?

Question 2: What prevents cold blooded animals from making heat?

Question 3: Don't they need ATP? Do they use different types of reactions to make energy?

Question 4: Do they have different evolutionary path? They don't seems very different from us.