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The Science of Vampirism

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Adaptations in their skeletal and muscular systems give vampires significant advantages over humans. Not only are they superb athletes with enhanced strength and speed putting them on par with even world-class sprinters and weightlifters, they can also perform much longer before fatigue sets in.

Vocal Folds: During the coma, structural changes in the larynx cause vampires to speak more quietly. As a result, their voices crack when they try to shout, which is why they prefer to hiss, expelling air through their clenched mouths. Over the years as their mucous membranes thin and they lose elasticity in their vocal cords, a male vampire will develop a higher, thinner-sounding voice, while a female's voice will deepen. Contrary to some fiction, vampires do not growl like wolves or roar like lions, but they can emit high-pitched shrieks if they scream loud enough.

X-ray of a vampire's curved spine

Muscles/Connective Tissue: About 90% of vampiric muscles are of the fast-twitch variety (compared to 50% for the average human). This brand of musculature enables short bursts of maximal force, ideal when hunting prey. However, unlike typical fast-twitch muscles, vampiric muscles are highly resistant to fatigue, thanks to a drastic increase in myoglobin and mitochondria. Much like cardiac muscle, this allows a greater amount of activity without lactic acid buildup. This makes a newly-turned vampire 3 to 5 times stronger than before transformation, with a top running speed of 25 to 30 miles per hour, and a vertical leaping ability of at least 10 feet. Ligaments and tendons thicken in response to the workload imposed upon them by the muscles, and gradual fluid loss causes a vampire's muscle tissue to shrink by roughly 35% (with no apparent loss of power). Starving vampires lose even more water weight, as well as muscle protein, but these discrepancies can be regained after feeding. Because of the extra feeding required, bodybuilders rarely continue their profession after transformation, causing their extra musculature to waste away over the course of a year.

Skeletal System: Osteoblast production causes a vampire's entire skeleton to harden and thicken, both during the coma and after each feeding. This makes their bones much more efficient at absorbing shock from high-impact forces such as jumping, falling, blunt trauma, and even bullets. As a vampire loses its fat and water stores, its overall height will shrink down by 1 to 3 inches, due to a gradual contraction of the ligaments between the joints and spinal vertebrae. The former symptom results in frequent crackling and popping of the joints, while the latter causes the spine to curve into a hunchback (a condition known as kyphosis). The taller a vampire is, the more height it will lose, since a longer spine will curve more than a shorter one.

Respiratory & Digestive System

A vampire's slowed metabolism allows them to survive on a purely-liquid diet, as well as less oxygen.

Respiration: Because vampires don't produce much body heat, oxygen use is cut down by roughly two-thirds. Along with the fact they can absorb more oxygen with each breath, this allows them to go significantly longer without drowning or suffocating. For example, while an average human takes 12 to 20 breaths per minute (at rest), a vampire takes only 3 to 7.

What vampires are most known for

Saliva: As with vampire bats, vampiric saliva contains a potent anticoagulant known as Draculin, which makes blood flow much more easily down their gullets—and keeps it from curdling in the stomach so it won't be regurgitated. Vampiric saliva also contains a useful narcotic that renders victims less able to fight back.

Diet: As you may know, the average human body contains 5 to 6 liters of blood, but a vampire's stomach can only hold about 1.5 liters. While a pack of vampires has no problem draining a single victim, a lone vampire is forced to rely on a series of smaller feedings over a period of several hours. This is where its narcotic-like saliva comes in, as it keeps the victim sedated while the vampire goes back and forth between feeding and draining its bladder. Similar to humans with solid food, a vampire can go more than a month without drinking blood; but they're also different in that they can go equally as long without any kind of water, while humans can only go about a week.

A bottle of vampiric urine

Digestion:
Because blood is 50% water, half of it is shed through sweat and urine, and the other half through defecation. Depending on how often a vampire feeds, urination can take place anywhere from an hour after each feeding to once a week, with defecation on a weekly basis to once a month. Like other carnivorous creatures, the high iron content in human blood makes vampiric excrement completely black. Depending on how often they urinate, it can be anywhere from clear to tea-colored.

Fat: Vampires experience a noticeable degree of weight loss during the coma, since they require a tangible amount of fuel to change their body structure—hence why they're starving by the time they wake up. Vampires who are overweight will shed the extra pounds over a matter of weeks, thanks to their liquid diet and highly active lifestyle. Despite the rapid weight loss, hanging skin is never a permanent problem for a vampire, since victims who are obese/old enough to cause irreversible skin stretching never survive vampiric comas anyway. Needless to say, vampirism is not a recommended weight loss remedy.

Photo Credit: Stu Spivack

Dietary Substitutes: Vampires have trouble digesting solid food, and soup is one of the few forms of sustenance they can hold down. During the Middle Ages, vampires in urban areas often opened secret restaurants called potages, after the French word for "soup." These restaurants became their de facto meeting places, as well as shelters where they could hide out from hunters. As a result, soup became a symbol of brotherhood among the vampire race, and only the most trusted civilians were invited into their potages. Vampires are also very limited in what they can drink: carbonated beverages such as soda and beer are hard on the stomach, alcohol has a more adverse effect on the brain and liver, caffeine causes intense headaches, and they're lactose intolerant.

Dietary Restrictions: Aside from the fact that vampires can't consume much else other than blood, they're also limited to mostly human blood. While they can live several weeks on non-human mammals, such a diet does not supply all the nutrients essential for their survival. Non-mammals, such as birds and lizards, will only do for a few weeks. Vampire blood is by far the worst substitute. In 1928, the Goessman Institute supplied a total of 20 starving vampires with a plentiful diet of vampire blood. Although sated at first, they became lethargic and disoriented after only 3 days. Within 10 days, all 20 vampires were dead. To put it simply: vampires must drink the blood of humans, or die. It is this simple equation that drives their powerful survival instinct. Not even blood bags will do for more than a few months, as vampires absolutely require that thrill of hunting—as well as sufficient amounts of fear hormones from their victims—to effectively metabolize each meal. This shouldn't come as a surprise, considering that vampires have spent their entire evolution feeding directly on living humans against their will.

Nutrition: For more information on how vampires utilize human blood, see the CDC article on vampire nutrition.

Cardiovascular System

The most profound differences between our species are found in the circulatory system, as they enable vampires to survive injuries that would kill a human being. Fortunately for us, their tissues are still vulnerable to most kinds of poisons, toxins and venoms.

Human arterial blood (top) compared with that of a vampire

Blood: Known as ichor (pr. ik-er), vampire blood takes on a much darker color due to an increase in iron, bile and other toxins that escape from the liver and spleen. This ichor darkens even further over the next three to four months as a vampire feeds and replaces its blood supply. Although vampire blood may appear brown or black, arterial blood is actually a dark rusty red when diluted. The extra iron not only darkens the blood, but makes it clot faster as well. And although a vampire's oxygen intake is lowered by its slowed metabolism, the blood oxygen itself actually increases thanks to the added iron storage in the new hemoglobin and erythrocytes.

Heart: Vampire blood is pumped via the contraction of skeletal muscle rather than the heart, which eventually atrophies from disuse. This forces high-pressure venous blood toward the heart, which constantly swells and drains as low-pressure arterial blood is pushed away from it. While at rest, involuntary spasms known as fasciculations take place in the limbs, and emanate from the furthest extremities inward—similar to the wave-like peristalsis of the GI tract. Since it affects the muscles required for movement, slight tremors are common, but only when the muscles aren't in use. Voluntary diaphragm and abdominal action also aid blood flow to the brain. Along with their claws, hand tremors can be a dead giveaway for a disguised vampire, so they'll try to keep them out of view while in public.

Humans also pump blood this way, though it's strictly voluntary.

BPM: Normal healthy humans experience a resting heart rate of 60 to 100 beats per minute, with the average being 72. Since vampires lack a working heart, bpm must be determined using a single area of fasciculation. There are three in all: calves, thighs and biceps. The former are tensed first, then the latter two simultaneously, and then all three are relaxed at once—a process that takes about a second to complete. These points of contraction are called vasonodes, or simply "nodes." A newly-turned vampire starts out with a node bpm of around 50, which drops into the 30s over the next few days as its yellowed skin turns blue. Over the next few months it finally stabilizes into the 20s, and sometimes even the teens, with the record being a mere 10. Like fully-functioning hearts, these muscles will pump harder and faster in response to physical exertion, while the opposite occurs during sleep.

Some humans experience fasciculations as well.

Blood Pressure: Because the skeletal muscle pumps take over circulation from the heart, the cardiovascular system experiences a drastic pressure reversal: the veins now exceed the arteries. This is referred to as introverted circulation, or "undead circulation," while normal humans possess extroverted circulation. This is sufficient to sustain a vampire, as not only do their cells require less oxygen, the blood itself can transport more of it at once, and most of the arteries flow with gravity rather than against it. A couple exceptions are the carotid and vertebral arteries, but the lower veins and arteries constrict enough to allow as much pressure as possible toward the brain. Perhaps the biggest upside to this reduced blood flow is that it also helps the blood clot faster, preventing fatal bleeding even in major arteries.

Adrenaline: This "emergency hormone," produced by the adrenal glands, is released in consistently large amounts in vampire blood during "fight-or-flight" situations. This quickly raises a vampire's sluggish metabolism by increasing blood flow, dilating air passages and accelerating the production of clotting factors. Along with changes in muscle, bone and connective tissue, this ability to release adrenaline only adds to a vampire's extraordinary power.

Disease Resistance: In addition to natural antibiotics that slow the growth of harmful bacteria, most viruses are simply incompatible with vampiric cells thanks to changes in their surface proteins. For reasons tied closely with their lack of aging (as detailed later), there has also never been a reported case of a vampire having cancer; in fact, vampires who had cancer when they were infected lose all traces of the disease within a few months after transformation. This resistance to disease is not surprising, considering that the HVV virus can infect every tissue in the body without causing cancer or fatal bacterial infections.

A vampire after taking four bullets to the chest, resulting in only about 20% blood loss. Date: November, 1815.

Clotting/Healing: Vampire blood clots much faster upon injury than with humans, which plays a major role in why they're so resilient. Stabbings and gunshots to the torso—including the heart—are largely ineffective as a result, since a typical wound only results in about 5% blood loss, and vampires can lose over half of their total blood volume and still survive (if they feed soon afterward). Healing rate is more than doubled as well. Along with increased iron levels, this is in thanks to the larger number of blood cells responsible for clotting and tissue repair, as well as the fact that blood flow is quickly drawn away from open wounds. Vessel obstructions never seem to be a problem for vampires, since they don't suffer from fatty plaque and the body is better at dissolving clots inside healthy vessels. These adaptations likely came about from the Ebola-like hemorrhaging of vampiric comas.

Intestinal Injuries: While untreated stabbings and gunshot wounds to the stomach and intestines usually result in agonizing and fatal infections in humans and other vertebrates, it's only a temporary (though still painful) inconvenience for a vampire. The surrounding organs and abdominal wall are coated with a thick layer of antibacterial mucus which protects the body in the event of an intestinal breach—along with the fact that a vampire's liquid diet requires less gut bacteria. In addition, if any part of the GI tract has been severed, it will quickly mend back together over the course of several days, using the same process as a broken bone or severed tendon. The vampire will not be able to feed during this time (due to vomiting and possible diarrhea), and will usually go dormant until it is fully healed.

Pulmonary Injuries: As with bowel perforations, injuries to the lungs are rarely fatal: although a pneumothorax will occur when air leaks into the pleural space between the lung and chest wall, only a portion of the lung will collapse in most cases. As a result, vampires with chest injuries will typically experience dizziness, shortness of breath and eventual unconsciousness until the collapsed lung(s) can heal and reinflate over the next several days. Only in cases where both lungs suffer multiple perforations do vampires pass out before they can escape their attackers. Generally, death only takes those that are too malnourished to withstand the effects of oxygen deprivation—a hazard lessened by the vampiric ability to slow their metabolism in extreme circumstances.

Medical Applications: Along with their profound resistance to disease, there was considerable research into vampiric circulation and possible applications for human medicine. One such breakthrough was the ventricular assist device, which allows humans to live without a heartbeat. There's also a physical exercise based on this method of circulation, which involves tensing and relaxing one's leg and arm nodes while at rest. Not only does it strengthen the muscles, it also improves venous circulation and nerve control. As for faster clotting abilities, the problem of vessel blockage formation has yet to be solved.

Medical Complications: Depending on the particular model, a vampire wearing a pacemaker upon transformation may experience agonizing pain from the constant shocking of their paralyzed heart, until the device runs out of power. However, this only applies to the older models: the newer ones only shock the heart a certain number of times before deactivating. Victims bearing transplanted organs will always die, even if they're vaccinated before the coma. This is due to their chemically-suppressed immune system being too weak to combat the virus, which then strengthens the immune system enough to attack the foreign organ, which in-turn kills the host. Pregnant women who are bitten will always miscarry, and can even die if left unvaccinated (depending on how developed the fetus is). In fact, there were many cases of desperate women seeking out vampires and their blood to abort their pregnancies, starting from 1950 when the vaccine was created up until 1973 when Roe v. Wade was decided.

Continue to Part VI

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