In the hit HBO show “The Last Of Us,” nearly the entire human population gets infected by a contagious fungus that controls people’s minds and turns them into zombies.
The story is loosely based off of a real fungus in nature — the cordyceps or “zombie-ant fungus” — but the showrunners took a lot of creative liberties.
In reality, scientists have identified more than 750 different species of cordyceps, and 35 of them are believed to be moderately beneficial to human health. The ones currently found in nature each act in their own unique way, and target one very particular type of insect.
When a cordyceps spore infects an ant, the fungus grows tendrils called mycelia that takes over the ant’s body, steals its nutrients, and alters its behavior — before eventually killing it.
It’s the perfect fungus for a gripping plot, and the show got a lot of people looking closer, and more cautiously, at their mushrooms.
But when it comes to fungi, there’s a lot more to be thankful for than afraid of, says Giuliana Furci, a mycologist and founder of the Fungi Foundation.
“Fungal fact is way more impressive than fungal fiction,” Furci says.
On the latest episode of Seeking a Scientist, Dr. Kate Biberdorf (aka Kate the Chemist) explores this secret world — and how it impacts nearly everything around us.
What exactly are fungi?
Fungus is its own kingdom on the phylogenetic tree of life, and the largest one at that.
You might remember that the tree of life has three big branches: Bacteria (species with no nucleus), Archaea (single cell organisms), and Eukarya (species that contain a nucleus).
Plants, fungi, humans and animals are all eukaryotes. But if you look closely at the very end of the eukaryotic tree line, says astrophysicist and Star Talk host Neil deGrasse Tyson, “the common ancestor between all animals and all fungus split later than its common ancestor split from green plants.”
What does that mean? “Humans and mushrooms are more genetically alike than either humans or mushrooms are to green plants,” Tyson says.
Fungi of all shapes and sizes
Scientists now estimate there are between 2.2 and 3.8 million species of fungi worldwide, although we only know about 10% of them. And it’s not just mushrooms: the Fungi Kingdom includes members like yeasts, molds, lichens and conks.
Another thing we’ve learned is that there is a greater mycelium network that exists underneath and within the soil — the “wood-wide web.” And these networks are huge.
If you take a walk through the forest, there are about 300 miles of mycelium under every step that you take. The largest known mycelium, the Armillaria ostoyae, covers 2,384 acres in the Blue Mountains in Oregon. That’s more than 1,600 football fields of fungus! Scientists estimate that the organism could be anywhere from 2,400 to 8,650 years old.
Right around the time that “The Last of Us” premiered in 2022, the World Health Organization released a list of the 19 fungi most threatening to public health, in part to urge more attention and research.
One major offender is Candida auris, a yeast that invades the bloodstream and causes vexatious fevers. From 2013 to 2016, we only detected a few infections each year from Candida auris. But then something happened, and the infections started to skyrocket. In 2022 alone, there were more than 2,300 confirmed cases — and according to the CDC, some strains are resistant to antifungal medicines.
With the eyes of the world on fungi, Furci published an op-ed in Time Magazine last year: “No, You Shouldn't Be Afraid Of Fungi." In it, she argues that we cannot fear the entire fungal kingdom.
Furci wants us to remove our "fungus blindness" and invest more in researching fungi and educating people about them. “It’s time we give them the attention they deserve,” she says.
Fungi conservation
Giuliana Furci has been all over the world studying fungi. Furci’s mother moved from Chile to the United Kingdom after spending a year as a political prisoner during the 1973 coup.
When Furci was 14, she and her mother moved back to Chile and explored the region of Patagonia for the first time.
“It was here in Chile in my late teens that I discovered my fascination with nature, and then with fungi,” Furci says. “And I was scrambling through everything I could find to see how I could learn more about mycology.”
Furci started reading anything and everything she could find related to mushrooms and fungus, and eventually she connected with a Harvard professor, who took her under his wing with hands-on training. Now she’s a Harvard University associate and Chile’s first female mycologist of non-lichenized mushrooms.
“A lot of people think that it's just a lovely stroll through a warm, beautiful landscape,” Furci says of Patagonia. “But it's actually hostile and hardcore as much as it is beautiful and wondrous and exciting. And sometimes it's so windy that you can't open your eyes while you walk.”
Furci is particularly good at discovering fungi, something that’s extremely difficult to do. But Furci has learned what to look for and what clues to follow, and has helped with the identification of multiple new species.
In her day-to-day work, Furci sticks her hands in the soil, smells it, and sometimes tastes it. “Taste doesn't mean eating,” Furci clarifies.
“We take a small bite, we'll munch on it, we'll swirl it around our mouths and we'll spit it out. I repeat, we spit everything out, we don't swallow.”
Just to repeat: Do not traipse into the wilderness and randomly start eating every mushroom you find.
During one trip in Ecuador, Furcisays, “I was looking for a few mushrooms and suddenly I just was feeling that one of them was there. There's these little brown mushrooms that nobody would really stop for. And I was like, ‘I can feel it, I could feel it.’”
Furci decided to name this new species of magic mushroom — Psilocybe stametsii — after Paul Stamets, one of the pioneers of mycology and advocate for the medicinal use of mushrooms.
In addition to her plethora of fungi discoveries, Furci has published two Chilean field guides and, in 2012, started the Fungi Foundation, an NGO that’s been working for the last decade to expand fungi recognition in the public sphere.
Fungus is intertwined with all life and death on this planet, but it hasn’t necessarily been considered as a priority for conservation efforts. That’s why Furci, her foundation, and a team of fungal experts, scholars and environmentalists have joined together to push for the legal protection of the “three F’s”: flora, fauna, and funga.
Thanks to Giuliana’s work, Chile in 2013 became the first government to add fungus to environmental law.
But there’s still plenty to be done. Even the U.S. Endangered Species Act still doesn’t mention fungi specifically.
“We owe our lives to fungus,” Furci says.
Where can I hear even more about this topic?
Listen and subscribe to the first episode of Seeking A Scientist with Kate The Chemist, from KCUR Studios, available wherever you listen to podcasts.
Seeking A Scientist is a production of KCUR Studios, made possible with support from the Stowers Institute for Medical Research and design help from PRX.
This episode was produced by Dr. Kate Biberdorf, Suzanne Hogan and Byron Love, edited by Mackenzie Martin and Gabe Rosenberg, with help from Genevieve Des Marteau.
Our original theme music is by The Coma Calling. Additional music from Blue Dot Sessions.
