Aquarists Create Tiny Hats for Sea Urchins to Wear Because in the Wild They Like to Use Shells as Headwear

A new wave of urchinwear.

Sea urchins are among the most widespread and prevalent echinoderms in the ocean, with 950 species inhabiting seabeds. They are commonly referred to as “porcupines of the sea” due to their lengthy spikes, which act as a deterrent to predators. Despite this, sea urchins have a tendency to camouflage themselves with materials such as stones, shells, and rocks, and even don tiny hats, if they are given a chance.

Yes, some creative aquarists came up with the idea to 3D print top hats, cowboy hats, fedoras and even viking hats for sea urchins, not only to make them stylish, but also help to keep them safe.

Redditor VanillaBean5813 told Bored Panda that she and her parents started 3D printing tiny hats for their sea urchins as a family project after getting their first baby corals and the “sea urchins started carrying them away, which is damaging to them.”

Following the first hat designs, various enhancements were made. “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.”

It’s not entirely clear why sea urchins like to cover their heads, she added. “We think it’s either a defense mechanism for their vulnerable backsides or protection from tank lights.”

Emma Verling, a senior post-doctoral researcher at MaREI Centre for Marine and Renewable Energy, who has conducted research on the covering behavior of sea urchins, verified to Bored Panda that certain sea urchins utilize shells, stones, leaves, or algae to conceal themselves, but the rationale behind this conduct remains uncertain.

Numerous theories seem highly plausible, such as the notion that covering provides ballast, which anchors the urchins and prevents them from being swept away during powerful currents or winter storms. Additionally, these items may offer a physical safeguard against predators, serve as a form of visual camouflage against them, and protect the urchins from harm caused by UV light, among other possible explanations.

Verling ended her research with the 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.”

Regarding the tiny hats, she 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.”

And there’s no harm in adoring the sea urchins wearing them either.