Monster of the Week: The Werewolf

The beast of cannibalism. © Leonard de Selva/Corbis

Ah, how have we overlooked the werewolf for so long?

I think we can blame the moon.

The lycanthropic human is slave to the lunar cycle -- or so we've been told. When the full moon hangs fat in the sky, the afflicted individual transforms into a bestial form and woe to any human in their wake.

It makes for a lovely tale, but how are we to rectify it with our understanding of the natural world?

The Coming Darkness

Certainly, the moon exerts control over biological processes due to its predictable cycle of varying light levels. Even in the wake of artificial lighting, humans seem bound to the lunar cycle as well. A 2013 study from the University of Basel in Switzerland showed poor human sleep behavior during full moons.

Population control.

Some scientists argue that increased activity by large predators after a full moon may have instilled a genetic aversion to the sight of that pale, glowing orb in the night sky. Its mere presence, as explained in this 2011 paper from the University of Minnesota, would have told early humans that the nights ahead would grow in darkness and team with man-hungry predators.

So there is your possible correlation between a full moon and heightened activity by natural or unnatural creatures. But why would some humanoids transform into cannibalistic monsters? Let's explore...

Cannibal Morphs

Werewolves, by their very nature, feast on human flesh. Even our most ancient account of lupine humans, the Greek myth of Lycaon, revolves around the taboo of cannibalism. But what denizen of the natural world can serve as a parallel example? What other creature physically alters its form in order to dine on conspecific prey?

Bernard Picart/Art Media/Print Collector/Getty

For answers, we enter the world of the tiger salamander.

The tiger salamander life cycle features a forking road to two distinct types of larval tadpoles: normal and cannibal morphs. See, under normal circumstances, all the eggs develop into normal tadpoles and then into normal adult tiger salamanders. But if the population is too large for the available environment, consistent tactile interaction with other tadpoles causes some of the eggs to develop into tadpoles with larger heads, bigger mouths and more well-developed teeth.

In other words, tiger salamanders have a built-in population control system: larva-on-larva cannibalism. If the brood pool is overcrowded and resources too scarce, then some tadpoles physically change in order to better consume the others. After the culling, the cannibal morph retains its larger head and bigger mouth, even though its diet normalizes. It's pure economics.

Werewolf Economics

And so perhaps the werewolf is just a cannibal morph of homo sapiens. In the wake of cramped environments and limited resources, certain unnatural humans morph into cannibalistic monsters. Is it any wonder that we hear so many tales of werewolves in major population centers such as a London, Paris and New York City?

We are a vastly unsustainable species. Something has to cull the unruly herd. Draw blood.


Monster of the Week is a - you guessed it - regular look at the denizens is of our monster-haunted world. Sometimes we'll focus on the cultural aspects, but mostly we'll look at the possible science behind a creature of myth, movie or legend. Be sure to explore the Monster Gallery as well as the Monster Science video series.

About the Author: Robert Lamb spent his childhood reading books and staring into the woods — first in Newfoundland, Canada and then in rural Tennessee. There was also a long stretch in which he was terrified of alien abduction. He earned a degree in creative writing. He taught high school and then attended journalism school. He wrote for the smallest of small-town newspapers before finally becoming a full-time science writer and podcaster. He’s currently a senior writer at HowStuffWorks and has co-hosted the science podcast Stuff to Blow Your Mind since its inception in 2010. In his spare time, he enjoys traveling with his wife Bonnie, discussing dinosaurs with his son Bastian and crafting the occasional work of fiction.