There are few beach discoveries that feel quite as magical as finding a perfect sand dollar.
You are walking along a tropical beach, looking down at shells and pieces of coral, and suddenly there it is: a perfectly round, flat, almost porcelain looking disk buried in the sand.
It looks like some kind of ancient coin.
And in a way, it really is a coin from another world.
But there is an important secret about sand dollars that many beachcombers don't realize:
The beautiful white sand dollar you find on the beach is the skeleton of an animal.
Sand dollars are actually sea urchins
Sand dollars belong to the same broad group of animals as sea urchins and starfish: the echinoderms.
They are not shells.
They are not stones.
And they are definitely not coins.
A living sand dollar is covered in tiny movable spines and is generally much darker than the beautiful bleached white specimens people find washed up on beaches. Beneath those spines is a flattened body made largely of calcium carbonate.
The flat shape isn't accidental.
Sand dollars spend much of their lives buried in or moving through sandy sea floors, where their unusual shape allows them to live in an environment that would be extremely difficult for a normal sea urchin.
The famous flower is actually part of the animal
Pick up a sand dollar skeleton and you'll usually see a beautiful five petal pattern in the center.
It looks like a flower.
There is a reason.
The pattern is associated with the animal's five-part body organization, something shared by echinoderms such as starfish and sea urchins.
Depending on the species and condition of the specimen, you may also see tiny holes and intricate patterns across the surface.
A particularly intact specimen can look almost impossibly delicate.
And then you remember that this beautiful object was once a living animal crawling through the sand.
Panama has sand dollars on both coasts
This is where Panama becomes especially interesting.
The country has both a Caribbean coast and a Pacific coast, with an enormous variety of beaches, shallow marine habitats and islands.
Sand dollars occur in Panamanian waters, and researchers have documented several species.
For example, Leodia sexiesperforata has been recorded in Panama's Caribbean waters, including around Portobelo, where specimens have been found buried just beneath the sand in shallow water.
So if you're hoping to find one, don't just walk along the beach looking for white discs.
Look for living sand dollars in the shallow sandy seabed.
Portobelo is one particularly interesting place
The Caribbean coast around Portobelo is worth mentioning because sand dollar species have actually been documented there.
Researchers have recorded Leodia sexiesperforata from locations including Naranjo Arriba Bay and Minas Bay, and from Playa La Angosta in the Portobelo area, where it was found buried approximately 3 to 5 metres deep in the sand.
That last detail is important.
You may not find a sand dollar simply by strolling along the high tide line.
Some are living underwater and beneath the sand.
Bocas del Toro is worth exploring too
The beaches of Bocas del Toro provide another excellent place to explore Panama's sandy Caribbean coastline.
The archipelago has an enormous variety of beaches, from the easily accessible beaches of Isla Colón to the more remote beaches around Bastimentos and the spectacular Cayos Zapatilla.
But don't go to Bocas expecting someone to guarantee you a bag full of sand dollars.
That isn't how wildlife works.
The presence of sand dollars depends on the particular beach, seabed, tides, currents and season.
Instead, think of finding one as a treasure hunt.
The Pacific is different
Panama's Pacific coastline is a completely different beach environment.
It has stronger surf in many locations, large tidal movements and extensive sandy shores. The Pacific coast stretches from Chiriquí and Veraguas toward the Pearl Islands and beyond.
That enormous coastline means there are plenty of places worth exploring.
Areas around the Gulf of Chiriquí, Azuero Peninsula, Pearl Islands and other Pacific beaches can be fascinating for beachcombing and marine life.
But there is a trick.
Go at low tide.
This is probably the single most useful piece of advice for anyone looking for interesting marine life.
As the water retreats, it exposes areas that were underwater only a few hours earlier.
You can discover shells, crabs, tiny tide pools, sea urchins and other marine creatures.
And occasionally, your perfect sand dollar.
How to tell if your sand dollar is alive
This is important.
If you find a sand dollar that is dark, brownish, gray, purple or covered in tiny moving spines, leave it alone.
It is probably alive.
A living sand dollar should go straight back into the water.
The beautiful white specimens people usually collect are dead skeletons that have been naturally cleaned and bleached by the environment.
A living sand dollar is actually much more interesting than the souvenir version.
Watch closely and you may see tiny spines moving across its surface.
It is alive.
And it is doing some very strange things.
How does a sand dollar eat?
Sand dollars generally feed on tiny organic particles and microorganisms associated with the sediment.
Their body is covered in tiny structures that help move food particles toward their mouth.
Essentially, the animal is processing the sand around itself and extracting the tiny bits of edible material mixed into it.
Imagine spending your entire life lying under the sand, slowly moving through it and filtering dinner out of the sediment.
Not exactly glamorous.
But extremely effective.
Why do some sand dollars have little holes?
Those famous holes are called lunules.
They are one of the coolest adaptations of certain sand dollars.
The openings help water pass through the animal rather than simply pushing it around when waves or currents move over the sandy bottom.
Think of them as tiny built-in pressure relief systems.
Instead of behaving like a flat disk that gets easily swept away, the animal can remain much more stable in moving water.
Nature is an excellent engineer.
Finding one is better than buying one
If you find an empty sand dollar skeleton naturally washed onto the beach, it can be a wonderful little souvenir.
But don't start collecting living animals.
And don't assume that every beautiful shell, coral fragment or marine skeleton is automatically legal to remove from every beach or protected area.
Panama has extensive protected marine areas and national parks, and regulations can vary by location.
The safest rule is simple:
If it is alive, leave it alive.
If you're inside a protected area, check the local rules before taking anything.
The best sand dollar hunt
Forget walking along the beach at noon when the sun is blazing and everyone else is swimming.
Try going early in the morning or around low tide.
Walk slowly.
Look at the areas where waves have recently retreated.
Check shallow sandy areas.
Look for unusual circular shapes partially buried in the sand.
And don't just look for the classic white "coin."
A living sand dollar can be dark and almost completely camouflaged against the seabed.
That is when beachcombing becomes surprisingly addictive.
You find one strange object.
Then another.
Then suddenly you're walking along the beach staring at every patch of sand like a pirate searching for buried treasure.
And there is something wonderfully appropriate about finding them in Panama
Panama is a country of hidden things.
Hidden waterfalls.
Hidden jungle trails.
Hidden islands.
Animals hiding in trees.
Owls hiding in the darkness.
And beneath the shallow tropical water, there are animals hiding underneath the sand.
The next time you walk along a Panamanian beach and see what looks like a strange little white coin, stop.
Pick it up carefully.
Look at the five-petaled pattern.
Look at the tiny holes.
And remember that you're holding the remains of an animal that once lived beneath the tropical sea.
A sand dollar isn't really a treasure from the beach.
It is a tiny piece of Panama's underwater world that happened to wash up at your feet.