Back in 1983, when I was in primary school at Old Kings Elementary School in Flagler Beach, FL, located near 9805 N Ocean Shore Blvd, Palm Coast, United States, one day, I went to the school lab for the first time and saw a dead sand dollar’s dried skeleton.
I curiously asked an older student, who replied that it was an extinct thing, no longer present in the world, just like the dinosaurs.
Since then, I have become curious about marine life and eventually earned a PhD in Marine Biology from the University of Florida (UF).
You may also find sand dollars at beaches or souvenir shops, & wonder: Is a sand dollar alive? Are sand dollars poisonous to humans lying on the beaches?
So, Let me explain with a brief answer.
Sand dollars or snapper biscuits are creatures from the phylum Echinoderms, with about 150 to 250 species and around 750 fossil species. These species are distributed across various genera within the order, reflecting a rich evolutionary history and diversity.
Sand dollars are related to sea stars and sea urchins. They are found on the ocean floor at depths of 30 to 90 meters (100 to 300 feet). Living sand dollar can grow up to 10 cm (4 inches) in diameter. They feed on the decomposers of the ocean like like bacteria, fungi, alage phytoplankton, larvae, and small plant and animal matter by filtering out these particles from the water.
When sand dollars are dried and turn white, they are dead. However, if they are purple or brown, they are still alive.
Don’t remove sand dollars from the water, as they rely on a specific environment for survival.
Are Sand Dollars Alive You Find on Beaches?
Yes, sand dollars are living organisms if you find them in purple-brown color at beaches. They have a lifespan of about 6 to 10 years. They are closely related to sea urchins and sea stars, there are around 150 to 250 known living species of sand dollars.
Sand dollars live in groups called “beds.” According to Leah Biery of Sanibel Sea School, sand dollars have 50 hard bone plates made of calcium carbonate (CaCO3), called ossicles, which are connected by 60 muscles internally.
Sand dollars possess a nerve ring, digestive organs, and water-filled canals. Their bodies are covered with spine-like, hair-like structures called cilia, which indicate that sand dollars are alive. So, if you find them in purple or brown, leave them gently in their own environment.
Live sand dollars typically have moving cilia and appear purple or red in color. Their cilia fall off when they die, and the color fades, leaving behind a white skeleton. Alive sand dollars also secrete a harmless substance called echinochrome, which can temporarily stain your skin yellow.
How Can You Tell If a Sand Dollar is Alive?
Alive sand dollar is round with a flat front and back. If you see a sand dollar covered with tiny, velvety hairs called cilia, which are actually its spines and appear gray, brown, or reddish-purple, then it’s a living sand dollar.
In contrast, a white, empty, dried skeleton is dead. If you shake a dead sand dollar, it will make a sizzling sound. These are often found in abundance on beaches. Learn how to clean sand dollars at your home with proven steps explained by a marine biologist
Whenever in my leisure time i visit the best beaches in Florida for Seashells collection, I find live sand dollars too along with dried skletons but gently place them back into the water which is perfect for them.
If you look closely and touch the spines on a live sand dollar, they feel like hundreds of tiny, fuzzy fingers moving. After a few seconds, your skin may turn yellow, but it is not harmful; it is just a sign that the sand dollar is alive (so avoid taking it out of the water).
These spines help the sand dollar filter food and also serve as gills. Sand dollars consume sand particles to add weight, helping them resist strong ocean waves.
One Important Note:
Many people who visit beaches for seashelling collect live sand dollars without realizing they are killing them. If you decide to take them home, only collect white, dead sand dollars. You can learn about how to identify different types of seashells a complete guide for beachcombers.
How Do You Know If a Sand Dollar is Alive?
A living sand dollar has a purple or brown color, and you can see the spines on its body moving. When you place it on your palm, it may feel like hundreds of tiny fingers touching you. The fuzzy feel comes from its feelers (spines); gently touching it may leave a yellow stain on your palm or fingers.
Attention:
Don’t take a live sand dollar out of the water. Within a few minutes out of the water, they can die, as they depend on water for oxygen. Just think—could you survive without oxygen?
How To Identify Live Sand Dollars on Beaches?
Beachcombing is my favorite hobby, and when I visit, I often educate people there about marine life. In 2023, a beachcomber from Virginia took a live sand dollar(Mellita quinquiesperforata) at Sanibel and put it in her bag. I gently explained that it was a live sand dollar.
How could I tell? Its color was purple, and its spines were moving. I asked her to immediately place it back in the water, as it would die otherwise. She then asked, “Did it pee on me?” I explained that the yellow stain on her fingers was just a sign that it was alive.
Live sand dollars can move and respire oxygen through their spines, which have a velvety feel. This is a key difference from white sand dollar skeletons, which are dead.
How Long Can Sand Dollars Live Out of Water?
Sand dollars are fragile and sensitive marine living that can quickly succumb to stress when out of water. Depending on the environment, they can survive for a few minutes outside their aquatic environment.
Factors such as respiration through tube feet and gills, dehydration, and environmental conditions like humidity and temperature impact their survival. Prolonged exposure can kill them within minutes.
How Long Does a Sand Dollar Alive?
Sand dollars generally live 6 to 10 years, though some types, like the Pacific sand dollar, can live up to 15 years. How long they live depends on their environment, predators, and overall health.
1. Growth and Development
Different sand dollar species grow at different rates. For example, Echinarachnius parma reaches nearly its full size in about 6 years, while Mellita Grantii takes around 5 years. Growing to full size is important for their survival and ability to reproduce.
2. Environmental Influences
Several environmental factors affect how long sand dollars live.
a. Predators
Sea stars, crabs, and certain fish prey on sand dollars.
b. Habitat
Sand dollars prefer sandy or muddy areas in shallow waters. Pollution, temperature changes, and salinity can impact their health and reproduction ability.
c. Ocean Acidification
Rising carbon dioxide levels lower the ocean’s pH, making it harder for sand dollars to build their calcium-based skeletons, affecting their growth and reproduction.
Life Cycle of a Sand Dollar
Sand dollars go through four stages:
- Egg
- Larva
- Juvenile
- Adult
After fertilization, the eggs become swimming larvae, eventually settling on the ocean floor and growing into juvenile sand dollars. As adults, they contribute to the ecosystem by helping with nutrient cycling and sediment health.
How To Tell the Difference Between a Live and Dead Sand Dollar?
Difference Between Live and Dead Sand Dollar
1. Color
Live sand dollars are dark brown or purple. Dead ones are white or light.
2. Spines
Live sand dollars have tiny, soft spines. Dead ones are smooth and hard.
3. Movement
Live sand dollars can move a little. Dead ones don’t move at all.
4. Smell
Dead sand dollars can smell bad. Live ones don’t smell.
5. Inside
Live sand dollars have soft parts inside. Dead ones are empty.
Also Read:
- How to Clean Seashells Like a Pro [12 Bonus Tips ]
- Best Beaches for Seashells in Florida (A Local’s Guide with Expert Tips)
- Top 5 Seashell Identification Apps Recommended By A Marine Biologist
FAQs( Frequently Asked Questions)
What Does a Sand Dollar Look Like When It’s Brimming with Life?
A living sand dollar has tiny hairs to help it move. It looks soft and can be purple, green, or brown. It has star-shaped feet underneath to help it move.
Is It Ever Okay to Take a Sand Dollar Found in the Water?
It’s best not to take a living sand dollar from the water as it’s important for the ecosystem. If you find a dead one, it’s okay to keep it as a souvenir.
Can we touch a live sand dollar?
Yes, but you should not touch live sand dollars unnecessarily because Sand dollars are fragile marine creatures that can be easily damaged by physical contact.
What Would Happen If I Accidentally Touched a Sand Dollar with Something Living in It? Would It Hurt the Animal?
Touching a living sand dollar accidentally can hurt it. Your hand may not be clean, and if you transfer bacteria to it, it can die. Touching it forcefully may damage its body or cause stress. It’s best to avoid touching them.
Why Live Sand Dollars Are So Cool?
They are cute and rounded like biscuits, Live sand dollars have tiny hairs that help them move and eat. They can change color, to purple, green, or brown. Their star-shaped feet help them move along the sea floor, making them unique and interesting to watch.
A Live Sand Dollar vs. A Dead Sand Dollar?
A live sand dollar is soft, colorful, and moves with tiny hairs. A dead sand dollar is hard, white, and doesn’t move.
Conclusion
A sand dollar alive is a special ocean animal. If you find one on the beach, check if it’s alive. A live sand dollar is purple or brown with tiny, soft hairs. If it’s alive, gently place it back in the water so it can keep living. If it’s white and hard, it’s already dead, so taking it as a keepsake is okay.
Next time you’re on the beach, remember to look closely and protect these little ocean helpers.
