The Mysterious Appearance of the Ghost Crab
Ghost crabs are one of the most fascinating creatures found along sandy beaches worldwide With their eerie pale coloration and incredible speed, these crabs have captivated beachgoers for ages. But what exactly does a ghost crab look like? In this article, we’ll explore the unique physical characteristics and behaviors that define this cryptic crustacean
Title and Introduction
The ghost crab’s name offers the first clue about its appearance These crabs have a translucent white shell that seamlessly blends into the beach, making them seem to disappear like ghosts Their bodies are small, averaging 2-3 inches long, with a square shape when viewed from above. Their front pincers are a mismatching pair of different sizes. While they may look petite, ghost crabs make up for it with their lighting fast movements across the sand.
Color and Camouflage
The main color of ghost crabs is white or cream, providing ideal camouflage against the pale sands where they live. Their bodies are actually patterned with speckles and spots in shades of brown, yellow, and gray. These markings help ghost crabs further blend into the beach environment. The crabs are able to alter their coloration to match the specific sand color of a habitat. This adaptive color changing allows ghost crabs to become practically invisible!
Eyes and Vision
One unmistakable feature of ghost crabs are their eyes. Their eyeballs are perched high up on movable stalks that can rotate a full 360 degrees. This gives the crabs an incredibly wide field of vision to spot food, mates, and predators. The eyes themselves are very large relative to the crab’s small body. They have flattened corneas which are thought to reduce diffraction when spotting prey on land from their aquatic burrows.
Legs and Movement
Ghost crabs have five pairs of long, spindly walking legs. Their backmost pair of legs is the shortest, while the front legs are the longest. This leg length variation gives the crab a tilted stance. Having longer front legs allows them to move at high speeds, up to 10 mph across the sand! When startled, ghost crabs can zip away in the blink of an eye. They use just their first and second leg pairs when sprinting.
Claws and Digging
Male and female ghost crabs can be differentiated by their claws, or pincers. Males have one large claw for defense and attracting females, while the other claw is small. Females have two smaller, evenly sized claws used mainly for digging and grasping food. The inner surface of the claws bears short hair-like fibers that allow ghost crabs to trap and hold wet sand, creating a tight seal for their underground burrows near the shoreline.
Abdomen and Tail
Underneath the ghost crab’s square-shaped shell is a narrower abdomen, or tail section, which curls up under the body. Females carry clusters of thousands of eggs attached to abdominal hairs until they hatch. There is a small slender tail fan at the end of the abdomen which assists with swimming down into their burrows. Only the eyes and antennae are visible when a crab is fully retracted in its burrow.
Burrowing Behavior
Ghost crabs spend their days buried down in obliquely angled burrows dug deep into the wet sand. The tunnels can extend 3 feet down with varying widths. Ghost crabs are well-adapted for a semi-terrestrial life. Special gill chambers allow them to breathe underwater within burrows, while also extracting oxygen from the air if temporarily trapped on land. Pores in the shell surface also provide added respiratory exchange.
Nocturnal Habits
These crabs are primarily nocturnal, emerging from burrows at night to hunt for food across the darkened beach. Under cover of darkness, the crabs scour the high tide line for anything edible. You’re most likely to spot the ghosts crabs’ characteristic tracks and burrow holes dotting the sand during daylight hours. Sitting quietly at dusk provides the best opportunity to observe these cryptic crabs in action.
Conclusion
Galapagos ghost crabs in Galapagos
Where to see them: They can be seen on the beaches all around the Islands.
Even though you can see ghost crabs all day, they are most active at night, when they come out of their burrows to clean them or look for food.
Shorebirds and gulls are native predators but they are also preyed on by introduced rats, cats and dogs. They could also be at risk from marine plastic pollution.
There are currently no projects specifically focused on the conservation of the Galapagos ghost crab. But as part of our Plastic Pollution Free Galapagos program, we are working with others to figure out how dangerous marine plastic pollution is for wildlife.
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Together with partners from all over the Eastern Pacific, we are trying to clean up the Galapagos Islands of plastic pollution by finding out where it comes from, how it affects the environment, and how to solve the problem in new and creative ways.
How you can help
Please help us conserve the wildlife of Galapagos by donating today.
Ghost Crab Facts: the Crabs in Holes on Beaches | Animal Fact Files
How do you know if a ghost crab is a sand crab?
Ghost crabs, also called sand crabs, can be told from their boxy shape, their sometimes horned eyestalks, and the uneven size of their claws. They can move surprisingly quickly, and the fewer legs they use the faster they are.
What is a ghost crab?
Ghost crabs are a type of crab that is found on beaches around the world. They get their name from their ability to blend in with the sand, making them very hard to see. Ghost crabs are nocturnal creatures and spend most of their time in burrows that they dig in the sand. These burrows can be up to 3 feet deep and 6 feet wide.
What makes a ghost crab different from other crustaceans?
With several species to its name, each ghost crab possesses unique characteristics that make it stand out among other crustaceans. One common feature among all ghost crabs is their ghostly appearance. Their pale coloration provides excellent camouflage against the sandy beach backdrop, allowing them to blend seamlessly into their surroundings.
What color is a ghost crab?
Most ghost crabs have pale-colored bodies that blend in well with the sand, though they are capable of gradually changing body coloration to match their environments and the time of day. Some species are brightly colored, such as Ocypode gaudichaudii and Ocypode ryderi.