33:17
Nobody knows why some mushrooms are psychedelic. I mean, we know that they contain a compound called psilocybin, which messes with the brain chemistry of lots of animals, including humans. But we don't know why being psychedelic would be useful to mushrooms in the first place. Here are three of our best theories. Hi, I'm Cameron, and this is MinuteEarth. When psilocybin interacts with animals' brains, it causes the animals to behave in all sorts of unusual ways: spiders build bad webs, cicadas get abnormally frisky, slugs have seizures, and humans hallucinate. But what does a mushroom get out of making animals trip?
Scientists have considered tons of ideas - let's talk about three of them. The first is that fungi might not get anything from producing psilocybin. Maybe the compound is an evolutionary accident like our widow's peaks, or a relic from the species' past, like our tailbone nubbins. But this probably isn't the case; Nitrogen is a critical component of psilocybin, but most fungi that make psilocybin live in environments where there is little soil nitrogen. In order to produce psilocybin, fungi have to limit how much nitrogen they devote to
important tasks like growth and reproduction, yet some fungi make TONS of psilocybin. So, considering the cost, psilocybin must do something for these fungi. Another idea is that maybe it helps them fend off hungry critters… after all, soil-bound species make all sorts of chemicals whose bitter taste or toxins keep herbivores at bay. But psilocybin is neither very bitter nor toxic, and if it is a deterrent, it probably works through mind control. I'm not saying that psilocybin makes bugs hallucinate the same way we do - there's no evidence of that. But it makes fruit flies breed like rabbits, and can make entire ant colonies turn on each other -
these are behaviors that might distract these animals from munching for a while, or make them more vulnerable to predators, eliminating them entirely. But there's a problem with this idea, too: certain insect larvae feed happily on psilocybin-producing mushrooms, so while psilocybin might be a deterrent for some animals, it certainly doesn't stop all of them. A third idea is that psilocybin helps the fungus spread its reproductive spores far and wide. Like, say a slug munches on a mushroom, triggering a psilocybin-induced seizure.
That tripping-out slug with a belly full of spores might attract the attention of a toad, which might eat the slug, and then hop far away before it poops out the spores. But, this idea isn't perfect either because if psilocybin's job was simply getting animals to move its spores around, it's unclear why it would need to make animals behave weirdly, when simply being tasty and nutritious would probably do. So, despite a lot of study, scientists still don't have a grand unified theory of what psilocybin does for fungi. And it's possible there isn't one; maybe psilocybin is used differently depending
on the species that makes it, or maybe it's the chemical equivalent of a Swiss Army knife: you know, it is good enough at enough different things without excelling at a particular job. For now, the bottom line is that when it comes to our scientific understanding of psilocybin, there is still so mushroom for improvement. This video is made possible by our patrons, who are some of our favorite people on the planet!. And you can join them at patreon.com/MinuteEarth
