Vampire Biology

A person who comes out of a vampiric coma fully transformed will have undergone a number of major physiological changes affecting the various systems of the body. The information included below is only an overview; for a more detailed account, try two classic texts: Henry Gray's Anatomy of the Vampire and Vesalius' Five Books on the Structure of the Vampire Body.
Brain/Nervous System
A vampire's nervous system is similar to humans and has proven to be their "achilles heel." Injuries to the spinal cord and brain can devastating for vampires. While a vampire's spinal cord and nerves work as before transformation, a number of changes take place in the brain, and that altered brain chemistry goes a long way toward understanding vampire behavior.

Normal brain (left) shows serotonin activity; vampire brain (right) shows none

1. serotonin: vampires have much lower levels of this neurotransmitter. In humans, low levels of serotonin trigger aggression and risky behavior. A study of murderers on death row revealed low levels of serotonin in their brains.
2. dopamine: another neurotransmitter, dopamine induces feelings of well-being. In vampires, it is released during feeding and has a narcotic-like effect. Neural pathways activated in vampires during feeding are much like those found in addicts when using drugs.
3. circadian rhythms chemical changes in the brain that help us "rise and shine" with the morning light are reversed in vampires.

Sense Organs
Powerful sense organs gave vampires an advantage both in hunting and eluding capture. Sneaking up on them virtually impossible, as they are aware of your presence long before you are aware of theirs.

Normal eye (left); Vampire eye (right)

1. sight: in vampires, the iris in each eye becomes hyperdilated, giving them what appear to be black eyes. While this iris dilation gives vampires excellent night vision, it renders them effectively blind in daylight. In addition, vampires suffer inflammation of the sclera, making the whites of their eyes appear red.
2. smell/hearing: both senses are extremely acute, as vampires have double the receptor cells in their noses and ears compared to humans. In fact, vampires usually smell or hear a person coming long before they see one.

Hair, skin, teeth, fingernailsPart of the terror of encountering a vampire stems from dramatic changes to their outer appearance. Some of these changes are functional, while others remain a mystery.

The upper (l) and lower (r) eyeteeth experience rapid growth

1. Teeth: during vampiric coma, the upper and lower eyeteeth experience growth. Additional enamel is deposited on the crown of the tooth. Vampires will file the teeth to make them sharper for easier feeding.
2. Hair: vampires lose all their bodily hair within ten years of transformation (except for the tiny hairs in their ears, known as cilia).
3. Skin: a newly-transformed vampire has a sickly, pale yellow skin tone that turns to blue over the next few days. In time, the skin becomes more and more translucent, and a fine network of veins become visible under the skin.
4. Fingernails: vampire fingernails thicken and grow at a rapid rate. Vampires will file their nails to a point, which helps them in grabbing victims.

Circulatory System
The most profound differences between humans and vampires are found in the circulatory system. These differences enable vampires to survive massive trauma that would kill a human being.

1. Blood: vampire blood is called ichor (pr. ik-er). Modifications to hemoglobin in the blood cells makes vampire blood appear black.
2. the Heart: vampire blood is pumped via the contraction of skeletal muscle rather than the heart, which eventually atrophies from disuse.
3. adrenaline: this "emergency hormone," which normally kicks in during "fight or flight" situations, is found in consistently large amounts in vampire blood. The presence of adrenaline, along with changes in muscle, bone and connective tissue, account for vampire's extraordinary strength, speed and aggressiveness.

Seen through night vision, a vampire attacks its prey

Body Temperature
A vampire's core body temperature is only about 60 degrees, compared to over 98 degrees for humans. This marked difference proved to be a great help for modern vampire fighters, as it made vampires easily distinguishable from humans when viewed through heat-sensitive infrared imagery (note the difference between the vampire and human in the picture at right).

Muscular/Skeletal System
Adaptations in their skeletal and muscular systems give vampires significant advantages over humans.

1. Muscles/Connective Tissue: about 90% of vampire muscles are of the fast-twitch variety (compared to 50% for the average human). Fast-twitch muscles enable short bursts of maximal force, ideal when hunting prey. Also, vampire ligaments and tendons thicken in response to the workload imposed upon them by the muscles.
2. Skeletal system: vampire bones thicken, an adaptation necessary to support their newly-powerful muscles.

Aging and Life Expectancy
While no vampire on record has ever died of natural causes, vampires do undergo an aging process, just not in the same way as humans. Vampires do not age on a molecular/genetic level, but their life of hunting and eluding capture creates tremendous wear and tear in the form of injuries to bones and tissue.

A 125-year old vampire photographed in Spain, 1901 Note the curved spine and lack of hair

Because they presented such a danger to society, most vampires were destroyed long before the outer limits of their life span were determined. Ancient history offers some clues, however. In Ancient China, there was said to be one vampire in the emperor's court through the entire (eastern) Zhou Dynasty, which would put his age at 550. More accurate modern records have certified vampires of over 200 years old.
Contrary to the opinions of many theologians, vampiric longevity is not the result of some pact with the devil, but rather an ability to ward off the DNA damage that occurs during cell division in normal humans. Specifically, the protective caps on the ends of chromosomes known as telomers get chewed up over time in humans, but not in vampires.
Though their DNA may have the ability to resist aging, a vampire's appearance will change dramatically over time. Vampires lose all of their hair within 10 years of transformation. Over time, a vampire's fat stores shrink away and its skin becomes thinner and more transparent, giving it a withered, dried appearance. Aging also leaves vampires with a pronounced curvature of the spine.
Despite their rather feeble appearance, older vampires are still extremely powerful and agile. Many a vampire hunter has made the mistake of underestimating them.