No, caribous are herbivorous, and so do not eat meat. They are certainly not cannibalistic
They breath in oxygen and breath out carbon dioxide, like a human through it's lungs
There is no oxygen in space, the only foreign substance your likely to come across are gamma rays from the sun, or foreign planets. If in bare space, the side of your body pointing towards the sun...
o2 or oxygen
carbon dioxide is released into the air.