Creating the Ecology of the Tooth Fairy

Image Credit: Kimberley Nagle, Public Domain, Image Cropped

Teaching complicated ecological concepts to kids isn’t the easiest thing in the world. Sure, I can explain the Coriolis effect to a bunch of Bachelor’s students, but teaching geographic range expansion to a six-year old is a different prospect. I’m lucky in that I have a kid who is already quite interested in the natural world, but it doesn’t automatically mean that he’ll take on board things like evolution, biological invasions, the MacArthur-Wilson Theory of Island Biogeography. So whenever there’s a weird opportunity to relate my kid’s interests to my work, I jump at it.

Such an opportunity presented itself last week when he lost his first tooth. I reminded him before bed that when the tooth fairy arrived that night, he had to make sure he didn’t look at it. He asked what would happen if he did, and I absent-mindedly replied that they would explode. But why would they explode? I actually had to think about this one, and decided to go with the story that it was like when bees died after stinging you. This may have satisfied him, but not me.

Cut to an hour later, and I’m still thinking about this. Anyone who has listened to our podcast Cinematica Animalia knows how seriously I take my cryptozoology, so naturally creating a faux ecology for Tinkerbella dentata was of the utmost importance. I made an implicit promise in the opening paragraph that this article would have something to do with teaching ecology to children, so let’s look at a few aspects of ecology that are easily relatable to tooth fairies*.


The tooth fairy seems to inhabit Northern Europe, as well as other English-speaking countries like Australia and the US. So it follows that the species originated in Northern Europe, and spread (presumably a product of British colonisation) from there. What effect its introduction had on the local species we can’t really know, however I for one find it hard to believe that passenger pigeons were completely wiped out solely by human hunting.

The lack of a tooth fairy myth elsewhere in the world would suggest that the species was originally restricted to colder temperatures. Yet they apparently subsequently flourished in warmer continents, which suggests that the restriction may have been a product of other species which outcompeted them in warmer climates, which they were subsequently released from in the regions they invaded. Perhaps they were released from a predator, but no kid wants to hear about a tooth fairy getting torn about by a falcon.

Behavioural Evolution

Presumably their spread to North America and Oceania with Europeans suggests that the fairies evolved a fairly close symbiosis with Homo sapiens. They may have jumped from a primate relative to us like our lice have, or simply have evolved in concert with different Homo species.

One thing that has apparently evolved is the value they place on human teeth. If we look at the amount given per tooth as effort expended, then they are apparently putting much more effort into getting teeth these days (see this article on tooth fairy inflation). Either that or they have a keen understanding of human economics.

Population Hierarchy

I believe we’re looking at a colonial species here. It’s the only reasonable explanation that I can give as to why they’d explode upon being seen (admittedly a problem of my own making). Protecting the colony from discovery must be paramount. But if we run with that earlier bee simile, are those collecting teeth simply drones? Is there a hierarchical structure within a colony? What does a queen look like?

Screenshot from 2019-09-09 18-40-34

Demonic as they may be, Hellboy II’s horrifying tooth fairies may be a more ecologically viable interpretation of the creature than most (Image Credit: Hellboy II, 2008)


They must be eating the teeth, right? But there are much easier sources of calcium and enamel out there. I think that the tooth fairy represents a species that evolved from other woodland creatures who subsisted on skeletons and animal teeth. The ancestors of the tooth fairies probably moved in with humans in an effort to find a less plentiful, but lower risk source of food. If this is the case, it makes sense that tooth fairies didn’t turn up in our mythos until human populations in Northern Europe started increasing, as smaller, sparser populations of Homo sapiens probably wouldn’t have been able to sustain a semi-self-domesticated tooth fairy population.

There are so many more questions to be answered. How to they procure money to exchange for the teeth? Do cheater individuals exist? How do they react to the presence of plaque?

There’s a book’s worth of stuff here. But for now, above are at least some answers next time your kid asks you complicated questions about the tooth fairy.


*A “let’s not go into too much detail because God forbid I have to do any proper research” cop-out if I’d ever heard one.

Title image credit: Kimberley Nagle, CC0

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