Do Daleks Breathe?

Question

In Doctor Who Season 1 Episode 13, when Daleks swarmed out to enter the Satellite 5, they had to pass a measurable distance through space to reach it. They do it sans air.

Also in Season 1 Episode 6, a Dalek is shown without armor which appears to have some sort of mechanism (not anything like nose) in place of its nose. Which suggest they might actually breathe.

So the question is

• Do the Daleks breathe air?
• Do they have some other type of mechanism for absorbing air?
• Or do they need air at all?

Answer 1

First part of your question (Daleks in space):

• What most people consider to be the "Dalek" (the metal construct), is actually an (almost) all terrain, all environments combat suit - or more specifically something like a tank or ATV.
• The Dalek's shell houses armor as well as some kind of shielding technology.
• Considering both points I wouldn't believe them not being air-thight or open to outside influences (like vacuum or other hazards). This would be a rather ineffective combat vehicle.

The actual sub questions mentioned:

• Do the Daleks breath air?
  • I'd assume that, given the fact they are still living (but heavily mutated) beings. So they most likely still have some kind of metabolism, which would require external sources of energy or fuel (not necessarily oxygen though; but seeing the Doctor breath on Skaro, this is unlikely); and therefore some kind of life support systems (also as mentioned here). Keep in mind that their suit could act as some kind of closed system for this, so they don't necessarily have to eat or drink or stay in an atmosphere.
• Do they have some other type of mechanism for absorbing air?
  • I'm not 100% sure but I think the scene where you've taken the second picture showed at least some hinted at breathing movement, so they might still have lungs.
• Or do they need air at all?
  • As mentioned above, I'm rather sure they have to breath and I don't know of any fact contradicting that.

Answer 2

The creature inside the Dalek is a heavily mutated Kaled ("Genesis of the Daleks", Tom Baker era). Davros, who invented the Daleks, referred to the machines as "travel machines" but his actions in the series suggest this was just propaganda and that the machines were always intended to be weapons in the war against the Thals.

The inhabitants of Skaro all breathed the same air as Earth (based on Harry and Sarah having no problems with the atmosphere) so I'm assuming that the creatures inside the machine breathe air as well.

My impression of the show is that what we call a "Dalek" is essentially just a one-person flying NBC-protected tank.