The first rule of scavenging at the beach is to return living creatures to the ocean if you find them washed up on shore. And most shell collectors are always looking to pick up a beautiful sand dollar and add it to their collection. But given their unassuming appearance, how do you tell if a sand dollar is still alive?
To tell if a sand dollar is alive, check for cilia or tiny spines over the creature’s body used to move. If you pick up a sand dollar and the spines are moving, it’s alive. The species is also usually purple or brown when it’s alive.
Because sea creatures like sand dollars are urchins and immobile, it can be hard to decipher whether they’re alive. This article will tell you how to check which ones are alive so you can return them to the water and continue searching for those that are no longer living.
1. It Is Submerged
While the sand dollar is pretty dormant, it’s still a creature that shows tendencies like other living animals. Some of these behaviors include:
- Movement
- Eating
- Burrowing
They spend their entire life underwater, and you can start to differentiate between a live and dead sand dollar depending on where you pick it up.
Sand dollars use their spines to move around on the ocean floor and to dig themselves into the sand to stay safe. These creatures also bury themselves to avoid choppy waters that could carry them onto the shore.
As they grow older, most sand dollars develop thicker outer shells to prevent them from floating away. Younger ones usually swallow small amounts of sand to weigh themselves down, so they aren’t carried away by the current. As such, the entire life of a sand dollar occurs underwater, and you’re more likely to find dead ones on land.
Searching in Shallow Water
Many collectors wade into shallow water during low tide to look for sand dollars to add to their collections. However, most sand dollars in the water are alive and should be left alone. Conversely, some creatures on the beach may be freshly washed up and should be returned to the ocean if you suspect they’re living.
Sometimes, you may not find any sand dollars on the beach and may need to wade into the water to locate them. You can walk into the shallow water and lightly stir the sand to see what’s underneath. You may get lucky and find a sand dollar, and fortunately, there are other ways to check if it’s still alive before you decide to take it home.
2. It Keeps Moving
As mentioned, sand dollars use their spines to travel across the ocean floor and dig underground. These spines capture and transport prey to the sand dollar’s mouth. They capture tiny organisms like larvae and plankton, moving them across the body with spines before consuming them. The spines are incredibly active and indicate whether they are alive.
When you pick up a sand dollar, observe the creature, and you may notice tiny hair-like structures squirming around on the surface. If you see any movement, the sand dollar is alive and well and should not go home with you for your collection.
Sometimes, as a sand dollar is transporting food across its body, the spines will bunch up in specific areas where the food is passing. If you notice any movement or bunching on the surface, the sand dollar is most likely alive, and you should let it go.
Dead sand dollars will lose their spines in a few days, and you will notice the difference. So if you see a sand dollar without spines, or the spines aren’t moving after holding it for a while, you can safely assume it’s dead and take it home. If not, quickly return it to the water, as they can’t survive long outside water.
3. It Doesn’t Change Color
Live sand dollars come in a range of colors. The pigmentation differs depending on a few factors, including the location and age of the creature. Here are a few colors you may see on a sand dollar:
- Brown
- Purple
- Red
- Tan
- Gray
However, sand dollars that wash up on the beach and are left there get bleached over time and turn completely white. So if you find a white sand dollar, you can bet it’s dead and add it to your collection.
In some cases, white sand dollars may return to the water due to the tides, and it’s safe to pick them up since they’re bleached. However, if you find a red or purple sand dollar, you can bet it’s still alive, and there’s no point picking it up to check for further evidence.
The only time you should consider checking if a sand dollar with color is alive is when you find one that’s grey or tan colored. Most sand dollars begin to fade after they die, and gray is the first color that shows up.
So if you find a gray sand dollar, it’s best to pick it up and check if it’s moving to confirm whether it’s dead or alive. Remember, though, that some sand dollars may be gray while alive, so it’s always best to leave them alone if you’re unsure.
Aside from colors, sand dollars typically have five openings on their body to allow the ocean currents to pass through without taking them along. With all the color and movement, you should be able to see these openings clearly. However, it’s easiest to spot these areas on a sand dollar that’s bleached white from no longer being alive.
4. It Secretes a Yellow Substance
If you’ve lifted a sand dollar out of the water and can’t tell whether it’s dead or alive, you can hold the creature for about a minute (not longer if you think it’s still alive). The sand dollar will secrete a yellow substance called echinochrome, which stains the hands.
Fortunately, this pigment is harmless, and you can wash it off with soap and water. This yellow stain is a sure sign that the sand dollar is alive and kicking, so return it to the ocean at once!
Bleaching Sand Dollars
The sand dollar got its name because once the shell is bleached by the sun, these creatures look like the coins used by old American and Spanish explorers. As such, their white appearance, tied to this history, is one of the many reasons people so badly want to collect sand dollars on the beach.
Let’s say you pick up a tan or gray sand dollar you think is dead. You can be much more confident it’s dead once it’s white and has no cilia.
So how long will it take to turn white? A dead sand dollar will take roughly one day to bleach when exposed to the sun. If you find a sand dollar you know is dead and want it to turn white, you can speed up the process by bleaching it and then exposing it to the sun.
To bleach a sand dollar, here’s what you have to do:
- Fill a bucket with bleach and water in equal parts.
- Place the sand dollar into the bucket for a few hours. If you have multiple dollars, consider adding to the solution, so there’s enough bleach in the water.
- Once you’ve left the shell in for a few hours, carefully remove it and place it on a towel to dry.
- Once the sand dollar has dried completely, place it outside in sunlight for however long you need to until the surface turns white.
- You may still notice a few yellow streaks on the surface, but these will disappear with time and more sun exposure.
When bleaching a sand dollar, it is crucial to take it out after a few hours. Otherwise, the bleach can affect the calcified shell and even permeate it, causing the sand dollar to start smelling like bleach.
Cleaning and Drying
After your sand dollar has been bleached, clean it out thoroughly to eradicate any foul smells. Even though it’s dead, there may still be remnants of the sea creature. For more information on why some shells stink, check out this article: Why Do Seashells Smell Bad? Causes and Solutions
Before you use the sand dollar to do a craft project or add it to your home decor, getting rid of the dirt is imperative to eradicate the possibility of foul odors. Cleaning and drying it up under the sun will also prevent it from attracting pests, like insects or rodents, which may be drawn to the smell.
Final Thoughts
Sand dollars make excellent beach souvenirs thanks to their unique design and the almost surreal ‘star’ imprinted on their surface. As such, you can use them to create ornaments, wall hanging, and even lampshades! And adding them to any home decor can create a distinct aesthetic.
Just be sure the sand dollar is dead before you bring it home. Here’s a reminder of how to check if it’s still alive:
- It is still bright and colorful.
- It secretes a yellowish substance.
- The spines on the sand dollar are moving.
