Do slugs trip on psychedelic mushrooms?

Tripping the slug fantastic iStockphoto

So this is the research rabbit hole I've been down all morning.

Over the weekend I found myself on a farm -- a farm where donkeys frolic and where, in the nature of things, psychedelic mushrooms bloom from their scattered poops. As any southern farm boy or rural hippie can tell you, this is exactly where one may find mushrooms that contain psilocybin. The animals accidentally ingest the spores as part of their herbivorous diet and then poop them out -- so here the coprophilous fungi thrives.

Now at this point a wandering hippie may harvest the crop and take it all home to his black-lit, tie-dyed lair of cosmic contemplation. But he better be quick, because he's not alone in his shroomthusiasm. The slugs love them too.

Yes, the slugs -- those grotesque, pale-bellied gastropods who abandoned their shells eons ago yet still keep all their bodily orifices and genitals packed tightly round their face. If you can call it a face. They terrify me.

So here's the question: Do slugs trip on psilocybin when they consume it? Because in humans, the substance generates a wide variety of mind-altering effects. Time changes. Reality shifts. Sometimes we feel a deeper connection with the universe and openness to each other.

But what about slugs?

The answers are not as forthcoming as I'd hoped. But here are two areas to consider:

1. Slugs love a variety of mushrooms and not all of them are edible by humans. As pointed out in "The Handbook of Mushroom Poisoning: Diagnosis and Treatment," slugs thrive on mushrooms in the genus Amanita , home to the deadly destroying angel and death cap species. And according to mycologist David Moore, mushroom toxicity levels are aimed at deterring insects, slugs and small mammals after a single nibble. It tastes weird, so they give up after one bite. But humans? Well, as Moore puts it, "A large animal will eat the whole mushroom; then both will wind up dead..." So in other words, despite the slug's relatively small size, we're talking about gastropod that regularly dines on toxic fungi and we're talking small doses.

2. How intelligent are snails and slugs? Their nervous systems are relatively simple, which is why neruoscientists come back to gastropod studies time and time again. As we discussed in our episode "Junkies of the Animal Kingdom," various creatures consume psychedelic substances, but do slugs have the necessary mental faculties to get much out of it? Maybe not, but perhaps we don't give them enough credit. Here's a wonderful quote from S.M. Martin's "Terrestrial snails and slugs (Mollusca: Gastropoda) of Maine."

Terrestrial gastropods have an ability to learn, i.e., they display "intelligence." The malacologist William Healey Dall (1881) once wrote a serious account about a child who had pet snails ... that "recognized" her voice and distinguished it from others. Garth and Mitchell (1926) used physical stimuli (heat, light, electricity) to train specimens of a land snail to "run" a maze to a comfortable cool, dark place. Humphrey (1930) showed that the withdrawal response of N. albolabris disappeared upon repetition of a mechanical stimulus; i.e., the snail became habituated. Habituation disappeared after an appropriate rest. An unfavorable olfactory cue was used to train the slug Limax maximus* to avoid normally palatable foods (Gelperin 1975). Sahley et al. (1990) showed that an initially aversive odor to L. maximus can be made attractive if that odor were repeatedly paired with an attractive chemostimulant. According to Carew and Sahley (1986), the higher-order features of learning seen in L. maximus rival that observed in such star performers in the vertebrate laboratory as pigeons, rats, and rabbits!"

So do slugs "trip" on magic mushrooms? Perhaps I'm missing a definite study on the subject (if so, please let me know), but it seems like a case of "probably not," but if they're truly capable of rat-level cognitive function, then who knows?

* That's a great grey slug in case you were wondering.

About the Author: Robert Lamb spent his childhood reading books and staring into the woods — first in Newfoundland, Canada and then in rural Tennessee. There was also a long stretch in which he was terrified of alien abduction. He earned a degree in creative writing. He taught high school and then attended journalism school. He wrote for the smallest of small-town newspapers before finally becoming a full-time science writer and podcaster. He’s currently a senior writer at HowStuffWorks and has co-hosted the science podcast Stuff to Blow Your Mind since its inception in 2010. In his spare time, he enjoys traveling with his wife Bonnie, discussing dinosaurs with his son Bastian and crafting the occasional work of fiction.