Bears eat plants such as berries, and plants get their energy from the sun. So his energy source's energy source is sunlight, which also makes it his energy source
They are like that because they can't always be faulty and may have at least some spark of truth to this theory also as stated earlier a theory in scientific terms is just an observation so it can't really be turned down hence theory.
Emperor penguins have the ability to 'recycle' their own body heat. The arteries and veins lie close together so that blood is pre-cooled on the way to a penguin's feet, wings and bill and warmed on the way back to the heart. Emperors' feet are adapted to the icy conditions
