physiology

When a person is changed into a vampire, their physical appearance is enhanced, their eye colour changes according to their diet, their speed and strength are magnified and intensified, and they will gain an arsenal of weapons needed in order to hunt their prey. A vampire’s diet is a blood diet—they need to feed on blood to satisfy their hunger—or rather, thirst. But, a vampire may feed on human or animal blood. Human blood will more effectively satisfy a vampire’s thirst, and it makes a vampire marginally stronger, though. After a vampire has hunted, the blood strengthens their bodies, and they are able to think more clearly.  Also, the blood lightens their eyes and flushes their skin slightly.
Vampires are able to lure their prey to them using their physical beauty, scent, and voice. Their teeth become very sharp, and can cut through human/animal flesh with ease. To kill their prey, they can rip through the flesh of their victim, drinking their blood. They are also able to produce venom, which can turn another person into a vampire.
To become a vampire, a vampire’s venom must travel through your blood stream from the bite, assuming that the vampire doesn’t drain the body of its blood. The venom spreads for a few days (the actual length of time that the transformation takes in dependant on how much venom is in the bloodstream, and how close the venom enters to the heart), being pumped around the body as the heart keeps beating. The various physical changes that take place occur as the poison moves through the body. One of the changes that occur in the body is physical “healing” from the injuries that they may have had. The greatest pain begins when the venom is all the way through the body, through the heart, and it starts meeting itself in the veins again and then burning them dry. The venom moves slower than blood because it is thicker—each beat of the heart can only push it so far. The venom has to leak through every cell in the body before it ends, so the changing/burning process is slow. The final stage in conversion is when the heart stops—the point at which the person turns into a vampire.
A person’s body is “frozen” in the exact same state as it was in when the person was bitten by a vampire. All growth in the body in stopped when the person becomes a vampire. Their skin becomes very hard and smooth—like granite. All of the tiny facets of their skin glitter like diamonds in the sunlight.           A vampire’s senses, such as their eyesight, and hearing, are intensified to aid them while they hunt for their prey. Their sense of smell also becomes keener. Vampires do not need to breathe, they cannot sleep, and they cannot produce sweat, or tears. They also have no blood of their own—the only blood in their bodies is the blood that they have drunk.
Vampires have only one enemy— the werewolf. Werewolves were made in order to destroy vampires, and one of the only ways that a vampire can die, is because a werewolf can destroy it. The werewolves’ teeth and claws are so sharp that they can even rip through the vampire’s granite skin, and can tear a vampire to pieces. But, as demonstrated in Eclipse, vampires and werewolves are able to work together—if absolutely necessary. There is also a truce between the Cullen family and the Quileute werewolves in La Push. The Cullens have promised that because of their “vegetarian” diet, they are no danger to the humans in the area. But, if any one of the Cullens either bites or kills a human (there is no geographical boundary), or crosses the boundary that the Quileute people have set, the battle of the werewolves and vampires may start up again in the area. The werewolves have to keep their side of the bargain too though, if they tell anyone that the Cullens are really vampires, and then they have broken the treaty as well.
Some vampires may have additional abilities above other vampires—they may have a special gift, such as Edward and Aro’s ability to read minds, Alice’s visions, Jane’s illusion of pain, or Jasper’s ability to control the mood of those around him. Much in the same way that the physical appearance of a person is intensified when they are turned into a vampire (what is already physically there is enhanced), it is Carlisle’s belief that when a person turns into a vampire, that their best personal quality or trait they possessed while human is also intensified. Examples of this are Carlisle’s compassion, Esme’s ability to love passionately, Rosalie’s tenacity, and Jasper’s charisma.