Vampire Carrying Capacity

There is a scholarly paper making the rounds of the Internet (“Cinema Fiction vs. Physics Reality,” by Costas J. Efthimiou and Sohang Gandhi) that claims to have disproved the existence of vampires using math. Their central claim is that, if a vampire needs to feed once a month, and every vampire’s victim becomes a vampire, the vampire population would increase geometrically and the human race would be wiped out in a couple of years.

Everybody knows that vampires don’t turn their victims every time. That would be as ridiculous as … as vampires actually existing. Well, anyway. In this essay, I was going to rebut their argument with some more math, but I discovered it’s already been done. Brian Thomas does a wonderful job of explaining the population ecology of vampires and humans in Sunnyvale (“Vampire Ecology in the Jossverse,” easily Googleable), and he uses much more advanced math than I could ever muster. Oh, well. Go read both papers. I have only a few notes to add, and all I have to invoke is a little algebra.

There seem to be two major feeding strategies among vampires. As far as I can tell, nobody’s named the strategies, so I’m just going to call them “grazers” and “gorgers.” Gorgers are kind of like your pet snake – they can go for weeks without food, and then they go and drain all the blood out of a human body. Grazers suck peoples’ blood, but they don’t kill them while they’re doing it, and presumably they have to do it more often.

Since vampires don’t exist, I have absolutely no facts to go on. All the numbers that I’m using I have had to pull out of thin air. The only real number I have is this: the Red Cross says that a healthy adult can lose a unit of blood (half a liter) every eight weeks without suffering any ill effects.

Say one of your grazing vampires needed a unit of blood every night to “survive.” He’d need, as an absolute minimum, fifty-six humans to give the first human enough time to recover before coming back to feed on her again.

One vampire to every fifty-six humans and the Red Cross would be pissed.

But in light of those numbers, one vampire to every thousand people or so starts to sound pretty reasonable. A small town like Northfield could support a coven of 17 or 18.

For “gorger” vampires, the math is a little different. Here we’re not concerned with how much blood a person can lose without getting hurt, but with how many people are dying. Say a gorger vampire needs to consume one victim every two weeks. A vampire like this would increase the annual death rate of a population by 26. What the vampire needs, then, is a population big enough where that increase in the death rate won’t get people suspicious.

Remember those lovely population histograms from the Elves? Birthrate/deathrate calculations are going to come in handy again. In a nice Western country where the life expectancy is around 80, 1/80th of the people have to die each year to keep the population constant. So a population with an annual death rate of 26 would have x * 1/80 =26 or 2080 people. But wait – if a vampire moved into a population of 2080, the death rate would double. The local townsfolk would be knocking on Buffy’s door in no time. Let’s multiply that by a hundred. In a city of 208,000, there are about 2,600 deaths a year. Add a vampire and the death rate would go up to 2626. Such a vampire could plausibly manage not to get caught.

Notice that the gorger model supports a much lower population density than the grazers – one individual in a city of 208,000, instead of 17 in a Northfield. And there’s the fact that a gorger’s victims would be dying under highly mysterious circumstances – it’s hard to hide all those dessicated corpses. A gorger vampire would have to limit herself to people who won’t be missed, which would drive the vampire population density even lower. There are many questions left unanswered about the grazer strategy, too. How likely are people to notice a fang-shaped hickey and waking up light-headed in the morning? Still, if you’re a vampire, it pays to be a grazer.

9: Awesome Robot Pterodactyl


Warning: this blog post contains spoilers for the movie 9 (though not the spoiler for the really big secret).

9 does something that a lot of major, well-funded movies are not willing to do: it kills off characters. And it hurts. The MPAA’s rating of PG-13 is appropriate, so brace yourself for a difficult but thrilling ride.

At only 81 minutes, Shane Ackerman’s debut movie does not contain one iota of flab. A machine called the Brain has turned against us and wiped out humanity. The only survivors are nine little hackey-sack dolls. The Brain is still out there. It must be stopped, and it’s going to cost them.

As a matter of fact, the very tightness of the plot is one of the things I have to complain about the movie. 9’s creative team seems to be holding itself back from long, self-indulgent panning shots, but since the movie is so short anyway, I wouldn’t have minded slowing down to wander around in the neat world they’ve created a bit more. Only the major strokes of each doll’s personality are sketched out, and I think there could have been more there if they’d dug deeper.

But who the heck am I kidding? The robot pterodactyl was sweet.

On a technical note, I admire Ackerman & Co’s work at balancing the dolls’ narrative roles. I know from writing that when a bunch of characters have the same job, like members of a crime-fighting team, it’s hard to keep them from interfering with each other. Notice how the movie introduces the characters gradually and never allows all nine of the dolls to be in the same room together just to keep things from getting symmetrical. 3 and 4 are twins, so they have a different relationship to each other than they do to the other teammates, and there’s some factionation going on, so 1 and 8 are closer to each other than to the others.

9 is visually stunning, artistic, but also dismaying. The ending will leave you with a big, “But now what are they going to do?” It’s tempting to compare 9 to Wall-E, since they’re both post-apocalyptic animated films with cute robots for main characters. See Wall-E and then see 9 to cut the sweet, or better yet, see 9 and then see Wall-E to help you recover.

It’s true that the characters in 9 are simplistically done, but I’m still not going to forget 2 for a long time.

Uncle Silas

When Miss Maud Ruthyn, heiress, is orphaned, she’s sent to live with her creepy old uncle until she reaches her majority. Said uncle is suspected of once murdering a man to whom he owed gambling debts. Oh, and if Maud were to die somehow before becoming an adult, Uncle Silas would get everything. Her father arranged it that way in his will to prove to the world that Silas isn’t a murderer. Maud gets the delightful experience of being the pork chop dangled in front of the starving wolf.

Deliciously gothicky, but there’s still plenty wrong with this novel by J. Sheridan le Fanu (better known for his short stories). For one thing, scary it ain’t. “And … there was a bloodstain … on the floor!” is about as intense as it gets. Did the Victorians scare easier than we do, or did the authors just hold themselves back? It’s a depressing prospect to think that we live in a scarier world than in 1899, but compared to Chernobyl, Silas’s murderous history is pretty tame.

Ah, Maud Ruthyn. How I love to hate her. Throughout the book she vacillates between a fainting flower petal and an imperious little brat who knows she’s better than the menials because of her education and good breeding. I know she would have made for an acceptable heroine in the 19th century, but cultural relativism can only be carried so far. I’m still allowed to be upset when she’s denigrating her own gender (The weaker sex? The weaker sex? I do beg your pardon?), failing to play an active role in the ending, or eerily echoing Robinson Crusoe:

‘I want your hand, cousin,’ she said, at the same time taking it by the wrist, and administering with it a sudden slap on her plump cheek, which made the room ring, and my fingers tingle; and before I had recovered from my surprise, she had vanished.

And if you were expecting a twist at the end, which would be reasonable to do in such a suspenseful novel, you will be disappointed. Le Fanu tells you over and over that a certain event is going to happen. And then it happens.

Now that I’ve told you everything that’s wrong with the book, I strongly urge you to go read it. If you’re the sort of person who read Frankenstein for fun, not for English class, you will love it. The point of Uncle Silas is the mood, not its illiberal characters or preposterous plot. The haunted house of Bartram-Haugh abounds with creaky rooms, opium addiction, gypsy prophecies, and … Swedenborgians. Le Fanu is a master of suspense. Just as soon as you’re dying to know what happens next, he slows the story down. He draws out each excruciating moment as the massive conspiracy surrounding Maud closes in on her. I read the last five chapters all at a gulp (nearly making myself late for work) and finished gasping for air. It was only about an hour later that I realized nothing particularly cool happened. Le Fanu just writes it so well. Definitely recommended for any fan of the Gothic style.

Characters and Viewpoint

I’ve been reading a book on craft by Orson Scott Card lately* where he suggests, to make readers hate the villain, to make the villain really, really smart.

This isn’t true in every culture, but certainly the American audience resents any character who is smarter and better educated than other people. … We’re afraid of and resent people who know more than we do, and when they act as if they think it makes them superior to us, we hate them.

That’s sad. Card is probably right, and probably the technique works, but is it right to do it? Tapping into the worst part of people’s natures to make them feel something about a character? He also suggests making bad guys insane to make us hate them.

These are a couple of prejudices that it’s more or less still socially acceptable to have – I certainly couldn’t get away with having a scheming Shylock as my antagonist. But it’s not just that. I also take issue with his lukewarm acceptance of sympathetic, morally ambiguous villains.

When you separate sympathy from moral decisions – exactly what a judge and jury must try to do in a trial – you can’t be sure that your audience will reach the ‘right’ conclusions; you can’t be sure that they’ll agree with you.

What, am I going to hurt my readers’ brains?

Maybe this is why I didn’t like Seventh Son much.

I’d be interested to see what other amateur writers think. How do you build character? Do you add attributes to characters just to make them more evil/heroic, and does it work for you?

* Characters and Viewpoint, in the Elements of Fiction Writing series.

Robot Toilets!


San Francisco’s answer to the public restroom. These pod-shaped toilets dot the city every few blocks; they come with a page-long set of operating instructions and power doors that slide back when you push a button. When you are done, an electronic readout tells you it’s going through a “55-second cleansing cycle,” which I can only assume involves zapping the inside with ozone or something, because one can’t observe it directly.

I keep expecting Dr. Who to come bursting out of one of these things and go save the world.

Lentil Curry

I discovered that this recipe works quite well.

LENTIL CURRY

1 package (1lb) lentils
2 onions
4-5 cloves garlic
1 package (1lb) tofu
10 cups broth
handful of dark green leafies
curry powder to taste
half & half to taste

Rinse lentils, then cover in broth and simmer ~30 mins. Meanwhile, cube the tofu and sauté on high heat. You want the outside of the cubes to get nice and crispy. Caramelize the onions and garlic in the same pan. Add dark green leafies of your choice – I used the green tops of leeks because that’s what I had, but it should be very tasty with collards. Once those are wilted, add the whole caboodle to the lentils. Season with curry powder (maybe also some salt and pepper) to taste, then add half & half until it’s creamy. Serve on rice.

This makes a ton, probably enough for about 6 people.

The Art of Rough Travel: Advice from a 19th Century Explorer


Sir Francis Galton, inventor of the standard deviation, psychometrician, and distant relative of Charles Darwin, is one of those remarkable people of the Victorian Era who did a little bit of everything. In 1850 he joined an expedition to what is now modern-day Namibia for the Royal Geographic Society and lived there for two years. When he returned to England, he decided the best way to use his knowledge was to write his own version of The Complete Idiot’s Guide to Being a Victorian Explorer, for the benefit of future generations of pith helmets.

Thankfully, this peculiar text has not been lost to the mists of time. The Mountaineers Club had it reprinted in 2006 with modernized spellings. The result is highly entertaining.

The text is divided into several sections, beginning with “Preparatory Inquiries,” on through “Beasts of Burden,” “Food,” “Game,” and “Bush Remedies,” and finally winding up at “Miscellany” and “On Concluding the Journey.” Each of the chapters is logically organized and clearly written, so if an explorer can find what he needs to know to avoid being trampled by a charging rhinocerous.

There are places where it’s hard to believe this book is not a parody. What pith-helmety type would take a how-to manual along to dip into from time to time? Galton devotes two whole pages to how to make a proper pot of tea out in the bush, and now and then you run across un-PC little zingers like this one:

“Savages rarely murder newcomers; they fear their guns, and have a superstitious awe of the white man’s power: they require time to discover that he is not very different to themselves, and easily to be made away with.”

Therein, however, does not lie the value of The Art of Rough Travel. It is an absolute treasure trove for fantasy writers. Galton has inadvertently written the Idiot’s Guide to Problems that Fantasy Characters Face. How fast can I expect my hero to travel on his way to Mount Doom? Well, he can go about 3 miles per hour if he’s walking, or 4 if he’s walking fast. What if he’s traveling alone in hostile territory? He should tie his horse’s reins on a short leash to his wrist. If the horse hears something wrong, it will jerk its head up, and serve as an alarm clock. Okay, but what should he do if he runs out of food? See “Revolting Food, That May Save the Lives of Starving Men.” How much can his elephant carry? “The average burden, furniture included, but excluding the driver, is 500 lbs., and the full average day’s journey 15 miles.” The book is studded with little examples that would not just make one’s story more believable, but inspire stories of their own. Galton recommends that a traveler should get some jewels, encased in silver (it’s a non-irritant), inserted into the flesh of the arm and allow it to heal over. That way, if thieves steal everything including the clothes off your back, you still have a little money to fall back on.

Most of the time the advice is real, serious, and useful. The invention on flashlights has made Galton’s section on improvised candlesticks somewhat less relevant today, but the human body and keeping it alive in bad circumstances doesn’t change, and the wilderness is precisely the place you might find yourself without the modern conveniences that make you so different from the Victorians. Any good backpacker could find something to learn from this book, be it the right way to rappel down a cliff, tie a knot, or waterproof one’s bedding. I heartily recommend it to anybody writing an adventure story, or just anybody on the lookout for weird and fabulous ways to stay alive.