io9

Say hello to the bowel-loosening science behind the “zombies” of the Last of Us

Say hello to the bowel-loosening science behind the “zombies” of the Last of Us

There are many species of the Cordyceps fungus, but they’re all parasites, but the remarkable thing about about the fungus is the ability of some of these species to actually change the behavior of the host creature. So it moves in, causes rather disturbing-looking growths on the host, and then causes that host to act in such a way that the fungus is spread. In other words, it’s a scientific way of creating zombies.

The end of the world in The Last of Us is caused by a species of Cordyceps fungus, moving away from the normal insect and arachnid hosts into human, causing aggressive behavior and the spread of the disease. While this aspect of the story is science fiction, the actual behavior of the host creatures in nature is just as scary.

Once infected by the fungus, an ant is compelled to climb down from the canopy to the low leaves, where it clamps down with its mandibles just before it dies.

“The fungus accurately manipulates the infected ants into dying where the parasite prefers to be, by making the ants travel a long way during the last hours of their lives,” said study leader David P. Hughes of Harvard University.

After the ant dies, the fungus continues to grow inside it. By dissecting victims, Hughes and colleagues found that the parasite converts the ant's innards into sugars that help the fungus grow. But it leaves the muscles controlling the mandibles intact to make sure the ant keeps its death grip on the leaf.

The fungus actually enforces the ant’s body after death, growing in the “cracks and crevices” of the ant’s shell. This makes sure other fungi are kept out. There is actually an enemy in The Last of Us that develops a hard outer coating of the fungus, and it turns out that’s scientifically accurate, except the process takes places in ants, and not humans.

This makes the behavior the “Clickers” in The Last of Us even scarier. They're not thinking, not in any real way, their brains are being controlled by a fungal infection that is only interested in reproduction. The idea that a fungus can basically wipe out your body before moving into your brain and controlling your actions to spread itself is terrifying.

Now if you'll excuse me, I'm planning on taking a two-hour shower while screaming.