The Science of Fiction Q&A

Werewolf Transformation

How could werewolves turn from human to wolf, scientifically speaking?

I've been working on this for a while. It's a pretty tricky problem. Werewolf transformations vary wildly between fictions, from being painful minutes long endeavors, to instantaneous and voluntary. However, they all share a few common traits: size change, hair growth, and skeletal restructuring.

Let's look at each of them and try to find some solutions.

Size change

Most werewolves hulk out when they change, gaining height and muscle mass. Some others shrink, becoming small enough to be indistinguishable from a normal wolf.

The problem with sudden and spontaneous growth, is the law of conservation of mass. The law states that in a closed system the total mass must stay the same, barring nuclear reactions.

Given that werewolf transformations don't appear to be violently energetic or radioactive, we can probably rule out nuclear physics, so then were left with general chemistry. That means one of two things: either werewolves don't change weight when they transform, or they absorb matter from the environment.

Absorbing material from their surroundings is technically possible. Trees, for example, are mostly made of carbon pulled straight out of the carbon dioxide in our atmosphere. However, there's a bit of a hiccup with that: there is considerably less than a kilogram (1kg=2.2lb) of carbon in the volume of air that surrounds you at any given time. So even if you could metabolize that carbon quickly, you couldn't put on much mass. Sucking up matter from the ground isn't a much better option, as you have no way of guaranteeing the composition of it, and you'd need to explain how it's getting into the body.

That leaves what seems like the more likely possibility, that werewolves do not change mass. If they are changing size, they are doing it only through stretching, or inflating like a pufferfish.

I'm rather delighted by the notion that the giant werewolves in Twilight are maintaining their body weight as they expand, and in wolf-form have the density of couch cushions.

Hair Growth

Hair grows normally at around 15cm (6") a year. If we assume that our werewolves are growing hair out to match a normal wolf, that's around 6cm (3") of hair in less than a minute. That is around 19 billion times the normal speed of hair growth.

That runs us up against some limits of chemistry. Hair growth relies on a long series of complex chemical reactions. Reactions happen at a pretty specific speed, and while you can speed some of them up a little by adding heat, too much and the reactions occurring would change and you wouldn't get hair anymore.

Even if you could accelerate the process enough, you'd run into another problem: all chemical reactions either release energy (exothermic), or absorb energy (endothermic). I've been unable to determine if the long series of reactions that makes hair is net one or the other, but it really doesn't matter. At billions of times the speed, with hair growing all over your body, the result would be fatal. If the reaction is exothermic, so much heat would be released that you'd probably burst into flames. If it's endothermic, you'd freeze solid.

Not ideal.

We're not completely lost, though. What if the wolves are not growing hair, exactly?

Hair is thick, and tough, and durable. A wolf that's only a wolf for a few hours a month doesn't need that. They need something to keep them warm overnight and then shed at dawn. Hair would be a wasted investment. Instead, why not produce something a little easier to make, and a little less robust... like spiderwebs.

A tiny spider can produce meters of web in minutes. Why couldn't a werewolf be covered in glands that did the same kind of thing? They could excrete a fluid that puffed up and solidified on contact with air, kind of like silly string. That could give them a thick, lustrous coat of fur in seconds, without them bursting into flames.

It would likely take a while to build up the reserves of hair fluid, so they couldn't just shift back and forth constantly, but once a month, no problem.

Another possibility is that a change in skin color could exaggerate the appearance of hair growth. Many species have chromatophores that let them rapidly change color. Cephalopods like octopusses and cuttlefish can do some really impressive color-changing, so why not werewolves.

Skeletal Restructuring

Most werewolves are not the same shape as humans. At best, their muzzle extends and fangs grow. At worst, they completely change shape to be a quadruped.

Restructuring a skeleton is going to run into problems just like hair growth did. Growing and resorbing bones is a slow chemical process that requires precisely the right environment and raw materials. Add to that all of the moving of muscle connections and adjusting of skin so your wolves don't end up looking like pugs, and you've got a pretty impossible problem.

The most obvious solution to this, is that the skeleton does not change.

Stick with me, here.

Wolves and humans have fundamentally the same skeleton. Same bones in the same places, but with some proportional differences. This is true for all tetrapods. Even whales have the same bones as other animals.

What a werewolf needs to be able to transform isn't necessarily to change their skeleton, just an extreme version of changing posture. If their hips and shoulders are modified to rotate between bipedal and four-legged positions comfortably, and their feet are structured to stretch out and narrow when needed, you could get a pretty wolfy shape pretty easily.

If this sounds a bit far-fetched, there are examples in the animal kingdom of rather substantial changes in body shape being possible. Many venomous snakes can retract their fangs. Draco lizards conceal a set of gliding wings as part of their ribcage. If you've ever tried to pick up a sleeping cat, then you know how much length can be concealed in a compact body.

Then there's the goblin shark.

If you needed a way to justify your werewolves growing a muzzle without magic, there's your living proof that it's possible. The goblin shark has a jaw that's kept retracted most of the time to reduce drag while swimming, but can extend rather incredibly far to snatch prey. If they can do it, why can't a werewolf?

So there you go, werewolf transformation without magic. What I might have described is a shark-faced, spiderweb covered, color-changing, pufferfish, but with a bit of imagination and creative licence, all those could be crafted into a scientifically plausible werewolf.

Questions? Other suggestions for how this could work? Comments are welcome!