Funny,AnimalsNOV 23, 2020

Turns Out, Sea Urchins Like To Use Shells As Hats, So People 3D-Print Them Some Cool Ones

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If you've ever seen a sea urchin—you know what a peculiar, cool-looking little dude this echinoderm is. There are a whopping 950 species living on the seabed, making themselves at home in virtually all oceans and depth zones. But it turns out, these little spiky balls also exhibit covering behavior, which means that they use their tube feet and spines to move objects like shells, stones, and other ocean goodness around. And this is just one part of the story.

One Twitter user and biologist posted on Twitter that “I was today years old when I learned that sea urchins naturally use shells as hats to make them feel safer and camouflaged so some aquarists had the genius idea to make them tiny hats,” and it blew up with 18.6K likes and 4.1K retweets.

You heard it right. Tiny, 3D-printed hats for sea urchins are a new must-have among echinoderms, which make them look ten times more stylish, and a thousand times cuter. Some even say they protect their spiky bodies from UV rays, so it’s a win, win, and win!

This Twitter user has recently posted about the tiny hats for sea urchins and it blew up on social media

Image credits: ok_girlfriend

And they look like the most stylish spiky balls out there

Image credits: ok_girlfriend

Image credits: ok_girlfriend

To find out more about this cute project, Bored Panda reached out to the Reddit user u/VanillaBean5813 who shared it on the r/crafts subreddit. “Our sea urchins like to cover their heads, so we 3D-printed them some hats,” the redditor posted the photos of their sea urchins sporting hats 3 months ago.

u/VanillaBean5813, who preferred to stay anonymous, said that this is their family project. “My dad is the real aquarist (and also a redditor), I modify 3D models from the internet, and my mom runs the 3D printer.”

Meanwhile, sea urchins in the wild are sporting makeshift coverings of shells and stones

Image credits: ok_girlfriend

Image credits: ok_girlfriend

The idea was initially posted in this subreddit by a person claiming they 3D-printed some hats

Image credits: VanillaBean5813

The redditor explained that the project started when the family got their first baby corals and the “sea urchins started carrying them away, which is damaging to them.”

After the initial hat designs, they had several improvements. “We went through a few iterations of hats—we learned that hollow structures were too floaty and that caused them to lose the witches hat we made.”

u/VanillaBean5813 said that it’s not entirely clear why sea urchins like to cover their heads. “We think it's either a defense mechanism for their vulnerable backsides or protection from tank lights.”

Image credits: VanillaBean5813

Image credits: VanillaBean5813

Image credits: letsgetsalty

To find out more about whether scientists would approve of sea urchin hats, Bored Panda also talked to Emma Verling, a senior post-doctoral researcher at MaREI Centre for Marine and Renewable Energy. She conducted PhD research on the covering behavior of the sea urchin species Paracentrotus lividus twenty years ago.

Emma confirmed that some sea urchins do indeed use shells (and other types of objects like stones, leaves, or algae) to cover themselves. However, the reason for such behavior is unknown.

Many of the theories are certainly plausible, for example: that covering acts as a ballast to weigh down the urchins and prevent them from being washed away in heavy surges or winter storms; that the items provide a mechanical protection from predators; that covering may provide a visual camouflage of sorts from predators; that covering protects the urchins from being damaged by UV light, etc.

By the end of her research, Emma came to a conclusion that “different species may cover for different reasons, even that it might confer a number of benefits (such as UV, camouflage, or ballast) simultaneously to varying degrees.”

And it turns out, sea urchin hats come in all shapes and sizes

Image credits: riosouza

Image credits: riosouza

Image credits: riosouza

When it comes to tiny hats for sea urchins, Emma said: “I think the 3D hats are a fun idea, a great talking point, and a way to educate people as to the complex ecology of sea urchins… I honestly don’t see that they could do any harm in an aquarium setting.”

Having said that, Emma was wondering if they “will confer an actual benefit—this is the most interesting and also the most complex of your questions.”

“If covering prevents an urchin from sub-lethal effects of UV such as reduced overall health and reproductive ability, then those that cover more often would logically be more likely to survive into the next generation and their offspring would also be genetically more likely to cover. Over time, the proportion of individual sea urchins that cover would increase because they have a survivorship advantage (this is a very brief summary of evolutionary theory in general!)”

Image credits: riosouza

Image credits: riosouza

Image credits: riosouza

Emma concluded that although the UV theory is a lovely one, the difficulty is that “many different urchin species display covering, including, for example, some species in the deep sea, where not a shred of UV light enters. So why do those species cover—surely it cannot be to protect themselves from UV?” In the end, there’s no easy answer, as is usual with science.