
Have you heard of an animal that has nerves of steel, and literally eats metal for breakfast? This hardened, extreme creature survives where few others could, and itβs none other than theβ¦ sand dollar? Yep! And this creature has a lot to teach us about the value of adapting and evolving in the most challenging of situations.
Ever been on the beach with your family or friends, hunting for the prettiest shells you can find, and stumbled across a full sand dollar? Or half of it?
But do you actually know what one looks like when they’re alive?
There arenβt many of these unique creatures to be found, so letβs dive beneath the surface to discover the metal-eating, hardcore animals who survive in the places their ocean friends thought inhospitable.
When describing it to you for the first time, maybe mom or dad, grandma or grandpa called them smooth, round, or even silky. But did grandma ever call themβ¦ fuzzy? The truth is, these elusive critters look nothing like what you find in the sand at low tide. When these creatures are alive, they arenβt white. While youβd never imagine it, theyβre actually grayish-purple and fuzzy!
Ok, maybe it isn’t fuzz, but it sure looks that way!
You may see these creatures all the time, but Iβll bet you never realized theyβre this unique!
The βshellβ you may pick up on beach day is actually the skeleton of this unique creature. And it’s a pretty cool one, at that. The structure of their skeleton is a feat of evolution that allows sand dollars to stay on the sandy seafloor, strong currents and allβa place most marine life finds inhospitable. Their βfuzzβ is actually tiny spines, tube feet, and pincers!
If you pick up any sand dollar and observe it edge-on, it looks like an airplane wing alive with a flurry of activity: tiny spines, tube feet and miniature pincers called pedicellariae that carry out various tasks.
Amanda Heidt, KQED 1
Down on the sandy seafloor, the sand dollar has an average lifespan of 6 to 10 years, 2 and is most closely related to sea urchins. 3 Burrowing in the sand for protection and for food, 4 they stick up at all kinds of odd angles! They share the classic 5 βpetalsβ with their cousinsβsea urchins and starfishβand get this: they have no brains, just nerves. These former sea urchins evolved to be flat to reduce drag and slip through the currentβjust another way theyβve adapted to their harsh environment!
Ok, back up. Purple, fuzzy, metal-eating starfish relatives? This video turned my conception of this beach-comberβs prize on its head.
Not only is their look different from what youβd expect, but they are also hardcore – surviving in rough conditions and eating metal to weigh themselves down. Yeahβ¦ you read that right. As they shuffle along the seafloor on their small spines, they grab sand along the way, passing it up those spines and into the mouth. Eating the microscopic algae and bacteria on each grain, they grind up the sand but save the chunks of metal, swallowing them whole to ensure they can stay down on the seafloor without floating up or being swept away. 5
Itβs impossible not to be intrigued by these nostalgic creatures. What we might have thought was a cute souvenir to sit on our desks is actually the remnant of a tough, badass burrower. Take a look at this great video from Deep Look for a window into the life of a creature who you and I probably thought we knew a lot about!
Shoutout to Deep Look for this incredible view into a habitat we donβt often get to see. For more great science and nature content, check them out! I donβt know about you, but realizing that our assumptions about creatures like the sand dollar are totally incorrect opens a whole new door to the possibilities that exist out there.
Learning to adapt to our environment!
We humans should take notes from the sand dollar and learn to evolve, too! Maybe it isnβt by slimming down to an inch wide to reduce drag or swallowing metal to keep our feet on the ground, but there is certainly something to be learned about thinking outside the box and realizing that sometimes, the odd solutions are the best ones.
Perhaps itβs thinking differently about the way we exist in this new, online world thatβs been created in the last year. Maybe itβs learning more about the people around us so that we know how to best get through to them! Whatever it be, adapting to whatβs around us can be nothing but helpful.
And things are not always what they seem…
I never knew that picking up a sand dollar was akin to finding a femur – youβre just picking up a skeleton that used to be so much more!
The ocean is a challenging place to study. After all, itβs much easier to send a person into space than to the bottom of the ocean. 7 We know even less about the ocean floor than we do about Mars, Venus, or the Moon, 8 and on a planet where 95% of the ocean is unexplored, 9 who knows what possibilities lie beneath the surface.
For more intriguing animals who live in the solar systemβs most desolate places, check these articles out next!
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Read MoreAnd another important thing:
Next time you stumble upon a sand dollar on the beach, here are some guidelines to help you decide if itβs ok to take it home. Often us beach-goers accidentally take sand dollars while theyβre still alive, which is obviously not good. Before you take one home…
- Hold the sand dollar and watch its spines. If they move, itβs alive. (And if itβs alive, get it back in the water, stat!)
- Look at the color. If youβre seeing gray, brown, or purple, theyβre likely alive. If theyβre very white, theyβre dead and ok to take home.
- While alive, sand dollars secrete a substance that will turn your skin yellow. If you hold it and it leaves a yellow spot behind, itβs alive.
One other note: In many states, taking a live sand dollar from the beach is illegal, though laws vary about taking a dead one. βItβs best to check for signs at the beach, look at your state laws online or ask a lifeguard or warden working at the beach.β 10
11Hopefully next time youβre searching for a sand dollar or stumble upon one at the beach, youβll be able to shock your friends and family with your newfound sand dollar knowledge. And remember, if the sand dollars can evolve and adapt to crazy conditions, so can you.
Ellen
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Notes:
- Heidt, Amanda. βA Sand Dollarβs Breakfast Is Totally Metal.β KQED, 9 Aug. 2018, www.kqed.org/science/1932072/a-sand-dollars-breakfast-is-totally-metal. Accessed 21 July 2021.β ↩
- Monterey Bay Aquarium. βSand Dollar.β Montereybayaquarium.org, 2021, www.montereybayaquarium.org/animals/animals-a-to-z/sand-dollar. Accessed 21 July 2021.β ↩
- βEccentric Sand Dollar Β· University of Puget Sound.β Www2.Pugetsound.edu, www2.pugetsound.edu/academics/academic-resources/slater-museum/exhibits/marine-panel/eccentric-sand-dollar/. Accessed 21 July 2021.β ↩
- Ables, Jessica. βEchinarachnius Parma.β Animal Diversity Web, animaldiversity.org/accounts/Echinarachnius_parma/. ↩
- Heidt, Amanda. βA Sand Dollarβs Breakfast Is Totally Metal.β KQED, 9 Aug. 2018, www.kqed.org/science/1932072/a-sand-dollars-breakfast-is-totally-metal. Accessed 21 July 2021. ↩
- Deep Look. βA Sand Dollarβs Breakfast Is Totally Metal | Deep Look.β YouTube, 9 Oct. 2018, www.youtube.com/watch?v=dxZdBPDNiF4. Accessed 30 Oct. 2019.β ↩
- Stillman, Dan. βNASA – Oceans: The Great Unknown.β Nasa.gov, 2012, www.nasa.gov/audience/forstudents/5-8/features/oceans-the-great-unknown-58.html.β ↩
- Copley, Jon. βJust How Little Do We Know about the Ocean Floor?β Scientific American, 9 Oct. 2014, www.scientificamerican.com/article/just-how-little-do-we-know-about-the-ocean-floor/. Accessed 13 Dec. 2019. ↩
- Kershner, Kate. βDo We Really Know More about Space than the Deep Ocean?β HowStuffWorks, 7 Apr. 2015, science.howstuffworks.com/environmental/earth/oceanography/deep-ocean-exploration.htm. ↩
- Hoyt, Aliya. βIs It OK to Take Sand Dollars off the Beach?β HowStuffWorks, 6 June 2019, science.howstuffworks.com/environmental/conservation/issues/sand-dollars-off-beach.htm. Accessed 22 July 2021.β ↩
- Hoyt, Aliya. βIs It OK to Take Sand Dollars off the Beach?β HowStuffWorks, 6 June 2019, science.howstuffworks.com/environmental/conservation/issues/sand-dollars-off-beach.htm. Accessed 22 July 2021.β ↩