the consumption of blood in any breed or species of vampire is what fuels the body. Therefore the body must be able to break down these cells and more turning them into venom since vampires do not produce waste, they don’t even sweat really. They can eat human food but it takes longer to break down due to chemicals and additives put in man made food, and while raw meat can be broken down far quicker than say a burger or a piece of cake — it’s still vastly slower than bloods break down process. Therefore it’s more optimal for energy purposes to drink blood.

I am gonna play god and say animal blood has a different structure than human blood. The hemoglobin is shaped different and lack a certain enzyme or protein that human blood contains, therefore no matter how much animal blood a vampire consumes their body temp will always remain cool even in the break down process. The only time this changes is if the blood is infected, and the body much destroy the infection before the blood can break down and be recycled back into venom.

Vampires who strictly drink human blood, run at a higher body temp. Their cellular regeneration is faster and their ability to break down human food or actual substance is far easier. They run warm, like someone who’s sat out in the sun for a few minutes in the winter. It’s a fleeting kinda heat, but if a vampire over consumes their body temp can nearly rival that of a humans once again. Over production of venom will cause the body to run hotter, but in doing so the skin can develop a sort of heat rash as its cellular structure is warping and trying to adapt to quick enough to compensate for the sudden temperature difference.

Blood holds memories, it holds trauma and emotions. Not all vampires are able to access these things by simply drinking, but vampires who are highly empathetic or gifted or even more in-tuned to their humane side are able to visualize and read these things from their hosts. Feral vampires due to the brain breaking down ( lack of sleep, consumption of diseased blood in massive quantities, withdrawing from sunlight all together, and eating fellow vampires ) cannot read blood at all. It is nothing more than a brief quench to a rabid thirst, and the reason they are so desperate and quite unpredictable is because their cellular structure has begin to officially die. It has stopped regenerating and the breakdown of blood into venom is no longer substantial enough to keep the body running. They will eventually rot, wither, or starve into their final grave.