Nerd School: Big Smiles- The Dangers of the Walker Bite

by Joe on November 2, 2012

Previously on Nerd School: The Walking Dead- Off With Their Heads- Katanas in a Post-Walker World, If I Only Had a Brain- Biology and Headshots, Keep on Walking- How Walkers Get Their Groove Back

This article deals specifically with the TV Show up to Season 3 Episode 3. The article may contains spoilers for anyone not caught up.

Easily one of the most gruesome qualities of zombies is the tearing, skin snapping, aspect of their bite. We tend not to think about our quality as a natural predator outside of our ability to use tools, but we are equipped with a pretty ferocious set of chompers.

First off we have a pretty simple setup for our mouths. Our jaw consists of two main bones, the maxilla and the mandible. The maxilla is connected to our skull by a fused joint, but the mandible is on a hinge joint. Pretty much everyone is aware that we use this joint and the associated muscles to tear and chew our food. In the case of walkers, that includes other humans.

Inside the human jaw we have 32 teeth, each specialized to perform a specific function of eating. The front eight teeth are our incisors. These are designed for cutting into our food and slicing it into pieces. Next to the incisors are our canines. These daggers of the mouth are designed for piercing and holding our food as we eat. Finally we have our pre-molars which are designed for tearing, and molars which grind our food down so we can swallow. So our mouths are already designed to slice, pierce, tear and grind whatever gets into them.

The human jaw exerts around minimal 120 pounds per square inch of pressure on its food source, and you have to imagine that force channeling either into the thin line of your incisors, or the tiny points of your canines. That’s easily enough to strength to pierce skin which can be pierced by 0.00043511321319065 psi (3N). That of course is dependent on where in the body one is bit.

So when a walker bites, its incisors slice into human flesh, its canines sink into the muscle and fat, and the premolar tears the meat and skin back. Human skin has incredible elastic qualities. Over long periods time, it can accommodate incredible stretching. However, just like when eating chicken or pork, if given a quick pull, the skin snaps.

The Walker’s bite looks like it is designed to cause as much damage as possible to kill their victim. That includes not only taking out large chunks of meat, but also severing blood vessels so that the victim dies from bleeding out.

Finally if the bite doesn’t kill the victim, the bacteria in the walker’s mouth can cause any number of complications. A normal human’s bite is loaded with human-specific bacteria which would infect any wound. For example dog germs are generally (not always) harmless to humans. Likewise, human germs generally wouldn’t harm a dog. But human germs can harm humans. So a bite from a human mouth full of harmful bacteria would be more damaging than say a dog bite, even if the dog’s mouth is full of harmful dog germs. Now combine that with walker’s bite also containing bacteria from rotting flesh, creates a perfect storm of infection. Normally a human bite has an infection rate of 10%-15%, but add in bacteria like lactobacilius, or molds like Alternaria, Aspergillus, Botrytis, Cladosporium, Fusarium, Geotrichum, Monilia, Manoscus, Mortierella, Mucor, Neurospora, Oidium, Oosproa, Rhizopus and Thamnidium (all of which commonly grow on meat) means your chances of being infected with something nasty are greatly increased.

We know that the walker virus isn’t transmitted through bites. Everyone in The Walking Dead universe is already infected. The virus’ pathology shows that it is only “activated” after death. In order to spread the infection, the virus controls the host to move towards food, and bite the nearest victim. If the victim isn’t outright killed, the resultant infection would kill them later.