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Monster of the Week: Jaws of the Xenomorph

The pharyngeal jaw. ©Bureau L.A. Collection/CORBIS
The pharyngeal jaw. ©Bureau L.A. Collection/CORBIS

The "Alien" Xenomorph is a monster near and dear to my heart -- quite literally in fact, due to the parasitic embryo's current position inside my abdomen. So it's long overdue that I mention this delightful creature here on Monster of the Week.

Xenomorph biology and life cycle are far too involved to discuss in detail here -- and that's why you'll find it all related in detail in "How the 'Alien' Xenomorph" works by yours truly. But I thought I'd discuss one of it's more iconic features: that deadly pharyngeal jaw.

It's a secondary jaw and it emerges from the pharynx or throat -- hence the name. On Earth, the aquatic moray eel also boasts this feature, only flipped around. It catches prey in its outer jaw and then shoots its pharyngeal jaw forward to grab the food and pull it down the throat. When not in use, the eel keeps it folded away.

This UC Davis video illustrates it nicely:

The xenomorph's pharyngeal jaw works much the same way. The alien's secondary set of teeth rest on the end of a bony appendage that extends from the mouth (and then often into a character actor's face) before retracting. The creature can then withdraw the "tongue" entirely (leaving a gaping wound in its prey), or it can bite down with the small pharyngeal jaws and reel its victim into a ferocious bite.

It goes a little something like this:

Monster of the Week is a - you guessed it - regular look at the denizens of our monster-haunted world. In some of these, we'll look at the possible science behind a creature of myth, movie or legend. Other times, we"ll just wax philosophic about the monster's underlying meaning. After all, the word "monstrosity" originates from the Latin monstrare, which meant to show or illustrate a point.

About the Author: Robert Lamb is a senior writer and host at HowStuffWorks, where he co-hosts Stuff to Blow Your Mind. An avid science enthusiast, he boasts a deep love for monsters and a hankering for electronic music.

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