After the change, vampires’ physical appearance and muscle mass is enhanced and perfected, eye color changes, and they no longer need to breathe, though they often still do so out of habit, and feel uncomfortable without their sense of smell—the first warning of an impending threat or the smell of potential prey.

Vampires still need air to breathe which is why when Stefan was trapped in the water he was constantly dying and healing. So yes they would be able to survive in space but they wouldn’t be able to function.

When a vampire cries, their tears are blood. A vampire does not cry human tears, instead, they are blood tears. “Blood tears” are the tears of a vampire.

Vampires can drown, however as stated above, Vampires do not require breathing in order to function, and as such, can hold their breath underwater for an indefinite amount of time.

According to the mythos, vampires are unable to see their reflection in mirrors, and, surprisingly, the reason why is because of how mirrors used to be constructed. That simple layer of silver is what kept vampires from being able to see their faces in a mirror in the time of Bram Stoker’s Dracula.

One girl asked me why Alice had a bathroom and if vampires have to pee. No, they don’t (they use all the blood, creating no waste), but they do shower. (Hair is dead cells–the vampire transformation doesn’t affect it. If you’ve got split ends, sorry!

Vampires, like humans, are emotional creatures but have the benefit of controlling their emotions by turning them off. When they want to feel again, they can turn them on or dull their emotions by being in the “middle”.

A: Vampires do shower, but they don’t get dirty the same way we do. Outside dirt, yes–blood and mud and whatnot (though most vampires don’t get a spot on themselves when they eat–its all a matter of practice), but not sweat or body oils. (Hair is dead cells–the vampire transformation doesn’t affect it.

First: Every vampire, all day, must lie in consecrated ground. He can be stumped when in his ground, not when out of it. Second: All day a vampire is off side. Third: No vampire may enter a house uninvited.

Matthew Clairmont explains that vampires mate similar to lions or wolves: the female chooses her companion, and if the male agrees, they are mated for life. This becomes the sacred link in vampire social circles, as any attempt on a mate’s life will result in vicious retribution.

They usually hold their breath for one to two minutes while they hunt and feed underwater, and they are capable of staying underwater for up to eight minutes if undisturbed. They must make hundreds of dives every day in order to find enough food, as they cannot live or breathe underwater.

Vampires will not die without blood, but become extremely weak for lack of it. Vampires can hold their breath for an extremely long time, but do pant with exertion and so apparently do need to breathe (the first film also implies that they can drown).

Actually they do breath – their method of processing energy is much the same as that for living people, metabolizing oxygen and organic fuel. Oxygen from water however isn’t as effectively obtained by lungs as it is by gills so a vampire underwater isn’t as active as one in air.

After they’re transformed, vampires no longer have any need to breathe, which means they can remain submerged underwater for as long as they wish. Even though vampires don’t have any real need for air, they’re expected to feign breathing to avoid suspicion.