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Public Radio's Environmental News Magazine (follow us on Google News)

The Hermit Crab Housing Crisis

Air Date: Week of

Although hermit crabs are finicky, they will move into bottle caps and other trash if they cannot find a suitable snail shell. (Phone: Eric Heupel)

Hermit crabs are low-maintenance pets – all you need is a warm tank, table scraps and an assortment of snail shells. As the crabs grow, they inspect abandoned shells to make a new home. But demand for shells in the pet trade could leave wild hermits homeless. Makerbot, the creator of the first 3D printer for consumers, is testing out designs for plastic shells. But will the finicky crabs be impressed? Makerbot CEO Bre Pettis speaks with host Bruce Gellerman.


GELLERMAN: Consider the plight of the lowly hermit crab. You’ve seen them crawling around in glass bowls in pet stores and grade school science classes. Well, turns out many hermit crabs are homeless. Typically, the tiny crabs take up residence in the shells of deceased snails. When a snail dies, a hermit crab moves right in.

Problem is: snails die slower than the fast-breeding crabs multiply and grow. So there’s a scarcity of homes for hermits. But now there could be a high-tech solution in sight. Makerbot based in Brooklyn, New York, is the first company to produce a 3D printer for consumers, and now, hermit crabs. Bre Pettis is the CEO of Makerbot, and he joins me on the phone.

Mr. Pettis, thank you. Welcome to Living on Earth.

PETTIS: Thank you. It’s a pleasure to be here.

GELLERMAN: So, is there really a shortage of snail shells for hermit crabs to call home?

PETTIS: You know, hermit crabs live in a perpetual housing crisis. Not only are they faced with humans picking up their shells and taking them home but they are growing. So, they’re constantly growing out of their shells. So, if they can’t find a shell, they’re going to desperate measures. They’re sticking their butts into bottles, they’re sticking their butts into shotgun shells, and that’s just not pretty. We can’t have that.

GELLERMAN: (LAUGHS) So, where does Makerbot, your company, come in?

PETTIS: So, we make 3D printers which are machines that can make you almost anything. There’s a couple of approaches to the materials that you can use in 3D printing. You can use plastics, and we use ABS which is the same thing Lego is made out of, and you use a material called PLA which is made from corn so it’s biodegradable. And, as a community, we can actually do some science here, and we can create shells. And we can see if hermit crabs like them and if they do, we can give them a hook up.

Bre Pettis holding a Makerbot machine that "prints" 3D shapes.(Bre Petttis)

GELLERMAN: Your printers actually produce something in 3D? It’s a physical object?

PETTIS: You can create 3D models on your computer and then, just like a regular printer that prints in 2D which prints out a piece of paper, you send the model to the Makerbot and it builds it in 3D. Layer by layer.

GELLERMAN: So, why don’t you just make a lot of snail shells and distribute them to the world’s hermit crabs?

PETTIS: The first step is to create Makerbot-ed 3D printed shells and see if hermit crabs even like them.

GELLERMAN: Why wouldn’t they?

PETTIS: Well, you know, hermit crabs are fussy. So, it turns out in our first week that we found out that hermit crabs traditionally are right handed. That means they like shells that have a spiral that goes to the right. We had been making all left handed shells and they weren’t moving in. So, this week we’re reprinting shells, mirroring them and making them so they go the right direction, and we’ll see what happens.

GELLERMAN: You actually have hermit crabs there? They're kind of doing home inspections?

PETTIS: Yeah, so we set up a crabitat here in Brooklyn and then Miles Lightwood, the artist in residence, is setting one up in LA. And we’ve got hermit crabs moved in and we’re setting up webcams so we can observe what they’re doing.

One of the cool things about this project is we’re doing crowd-sourced science. Normally you think about science being done by people in lab coats in remote locations. We’ve got a crabitat and we’re basically asking the community to come up with shell designs. You know, maybe you have an idea where the shell is longer or shorter or you want to put a shell inside of a skull. Go ahead and design them, upload them to thingiverse.com and we’ll try them.

Plastic “printed” shells are in the crabitat to entice hermits into new homes. No luck so far - this manmade shell twists the wrong way. (Photo: Courtesy of Makerbot)

GELLERMAN: I know that hermit crabs are fairly fastidious. I guess when they find an empty, large snail shell the large hermit crab actually moves in and then they kind of get in line and the next biggest moves into the one that was just abandoned, and so on. It’s like a conga line.

PETTIS: Yeah, it gets … it’s definitely a little shuffle. It’s a communicated social life that they live.

GELLERMAN: So, how do you know that you have a happy crab that likes your shell?

PETTIS: We'll know that they like the hermit crab shells that we make for them when they move in - when they chose one. And, we’re just going to keep trying, keep trying new designs. If we have to, we’ll try new materials to print with. In theory, if we could come up with some sort of cement calcium carbonate shell material that was squeezable and then would harden like cement, we could make shells out of that, but that’s really living on the technological edge right there.

GELLERMAN: So, once you get your fix on a design, you can just, kind of, churn these out by the millions?

PETTIS: There’s kind of two parts to this. One part is: we can replace shells for hermit crabs in captivity, so you don’t have to go out and buy or collect shells from the wild. You know, we don’t want to go and dump a bunch of plastic on the beach and have them not be used. So, we’ll probably explore different options for having shells that are made out of biodegradable material.

I think it will also be interesting because if we do put them in the environment, we’ll be able to mark them and print numbers on them, so we’ll be to track them over time and see how it works.

The “Crabitat.” (Makerbot)

GELLERMAN: Six thousand people who use 3D printers right now, right?

PETTIS: That’s right.

GELLERMAN: How soon before it's coming to a home printer in my house?

PETTIS: So, while I think it would be really cool for you to have a 3D printer in your house, and I think everybody who experiences it has a great time with it, I’m most excited to get 3D printing in the hands of young people, because it’s an innovation machine. It's a machine that lets you to have an idea and make it and then make it again.

And that iteration is the core of invention. And if we can get these into the hands of kids so that they grow up just naturally designing and sharing and publishing and inventing things, then we’ve got a pretty bright future.

GELLERMAN: Well, Bre Pettis, thanks so much.

PETTIS: Hey, it’s my pleasure. My hope is that the listeners here will be inspired, come up with ideas, design shells, we’ll print them out and we'll see if hermit crabs will like them, and boom: we'll help a species.

GELLERMAN: Bre Pettis is CEO of Makerbot Industries, maker of a 3D printer and homemaker for hermit crabs.



Links: Video of a makerbot printing a Darth Vader head

Check out Thingiverse to see what creative minds have created with 3D printers

The Makerbot crabitat webcam


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