What exactly is the physiology of hosts in the Westworld TV series?

Question

We learn from Ed Harris that initially, the hosts were androids - mechanical robots made to look like humans. This is also seen in some flashback sequences, and Robert, the kid who opens his face to reveal the circuitry inside. In episode 6, we learn that the hosts were later switched to the current 3D-printing process, in order to appear even more human.

However, what exactly is their physiology? Their energy source? Do they need food or store it inside a stomach chamber? Or are they charged overnight, since obviously they do need a source of electrical power for remote control and data transmission?

Answer 1

According to showrunner Jonathan Nolan this will be revealed in Season 2:

Can you say how are the hosts powered? Like do they need to recharge? Do they eat?

Their construction and their power source is something we’re really going to get into during season 2. So we’d like to keep that mysterious.

They’re closer to biological than they are to mechanical, but they don’t suffer brain death the same way we do. They’re largely indistinguishable from a human beings, but their brains don’t require oxygen — which opens up interesting possibilities. Their brains are not as fragile as ours. On one hand, their cognition is controllable and malleable, but on a structural level they can’t be killed in the same way you and I can.

There are advantages and disadvantages to being a host. Season 2 we’ll be exploring more the nuts and bolts of what they are— as the hosts themselves are trying to understand.