Real-life zombies? An analysis of the science in 'The Last of US' on HBO

A new HBO hit show, called The Last of Us, is gaining popularity and possibly inspiring a fear of fungi.

In the show, a species of fungus infects humans and turns them into living zombies who then attack others while spreading the fungus. Sounds like a typical science fiction horror series. We can enjoy the show because it’s not real, right?

Well... yes and no.

Ophiocordyceps? Real-life zombies? What inspired the fungus in The Last of Us?

In an uncommon twist, the story for the show came right from a video game where fungi take over human bodies. However, the inspiration for the video game came from a real-life fungus that really does turn its hosts into zombies. Yes, there are real-life zombies in our ecosystem. A zombie occurs when a body is taken over by something else. It is truly fascinating and truly scary.

In this instance, a species of ant is taken over by a single spore of fungus called Ophiocordyceps. What happens next sounds like a science fiction movie… because now it is!

Once the fungus multiplies in the ant, it sends tiny spikes into the ant’s muscles. Next, the fungus produces a chemical that travels to the brain and takes over the brain’s functions. The zombie brain somehow instructs the ant to leave the colony and travel up to a nearby plant.  Once it gets to the top of the plant, the zombie ant chomps down on a leaf, its jaw locks up and it is stuck there forever.

Strange enough? It gets stranger. Next, the ant’s head basically explodes and large fungi branches grow out of the ant’s head. Then the fungi (growing out of the ant’s head) grow a structure that showers new zombie fungus spores on the ground near the former ant’s home in hopes that other ants will walk onto a spore, and the process starts all over again.

As scary as this is, it’s an evolutionary miracle and scientists are still not certain how it evolved. Ants live in packed communities and can tell if one becomes sick. Ants remove sick ants immediately so they do not infect the entire colony. Under this scenario, an ant infected with zombie fungus would be removed and killed before infecting any other ants and the fungi are not able to reproduce.

Somehow, in the millions of years of evolutionary history, the fungus developed a way to take over the ant’s brain and instruct it to leave the colony before the ants detected a problem. However, the fungus made sure the ant didn’t travel too far as it needed to spread the new spores around the colony later.

How many Ophiocordyceps species are out there?

There are currently 35 Ophiocordyceps species that are known to take over another species. However, scientists believe that there are likely more than 100 unknown Ophiocordyceps species that we have yet to discover. Because the steps needed for a fungus to take over a living body are so complex and specific, each species of this fungi is only able to take over a single species of insect. And this is what makes the HBO show unlikely to come true.

But here is the scary thing to think about. Your body has most certainly come in contact with one or more of these zombie-creating fungi. As a matter of a fact, the zombie fungi have very likely been in your body before. However, because of the specific nature of these fungi, they have no idea what to do in your body and are completely harmless.

In addition, this species of fungi cannot live in the warm temperatures of our bodies. The show does recognize this and addresses it by explaining that the warming climate has caused the fungi’s temperature tolerance to also evolve. This is not far-fetched and could happen. But remember, even if it could live in your body, it would have no idea what to do and would cause no harm.

To summarize, this show did its science homework to create a show based on real science. Of course, it stretches it to make it the hit that it is becoming.  Scientists say that while this fungus does exist here, you should be much more worried about real threats to humans – such as climate change.

The warming temperatures won’t turn you into zombies, but the end result for the human species may be the same.

Mike Szydlowski is a science teacher and zoo facilitator at Jefferson STEAM School.

Time for a pop quiz!

1. What is a zombie?

2. What science inspired the show The Last of Us?

3. Why does the fungus direct the ant to leave its colony?

4. Should humans be worried that climate change could cause this fungus to begin to infect humans?

5. What do scientists say you should be worried about more than human zombies?

Last week's quiz answers

1. How does the Great Lake Ice coverage this year compare to the average?

On a normal year, the Great Lakes would be around 30% ice covered.  This year, there is less than 5% ice coverage.

2. Explain two ways that humans can be impacted by less Great Lake ice? 

1. Less Great Lake Ice means that more big snows can happen near the Great Lakes.

2. Less Great Lake ice could mean a decrease in whitefish, which is important to the economy in the region.

3. The most intense lake effect snows occur during the first half of the winter season. Why?

The lakes are the warmest in early winter.   The warmer water would send the moister air up into the cold air.  As the winter goes on the water temperature drops and this would send less and less moisture into the air.  

4. How might the decrease in ice lead to a collapse of the Great Lakes Ecosystem? Would this impact humans?

Warmer waters would mean more invasive mussels, which eat more phytoplankton. This takes food away from the natural ecosystem and decreases the amount of fish that can be used as food.

5. What conditions would cause lake effect snows to happen later in the winter?

If the winter has been relatively warm, the lake water could still be warm enough to cause lake effect snows later in winter.

This article originally appeared on Columbia Daily Tribune: The Last of Us: Inside the HBO drama's zombie science