Education Blog

What’s that? The Atlantic Ghost Crab!

Ghost_Crab_image

During an ocean beach field trip in mid-November, an observant student found a dead, almost completely intact Atlantic Ghost Crab, Ocypode quadrata. It smelled bad, so none of the students wanted it for a keepsake, but I was fascinated with the crab, so I took it home to observe it more closely.

The carapace, or body of the crab, measures 1.5 inches in length, (males grow to 2 inches at maturity) and it’s the largest Ghost Crab I have ever seen. But that’s not saying much, because I’ve only seen about 3 or 4 in my entire life!  I realized I knew very little about Ghost Crabs, so I am sharing a few tidbits that I have learned in the past week.

Ocypode quadrata has a square-like shaped carapace, large eyestalks, unequal sized claws (in both male and female), long “hairy” walking legs, and is colored light tan or greyish white. They are well very camouflaged as they quickly move across the sand, and are active primarily at night, so that might be where the common name “Ghost Crab” originates. Their general range extends from Rhode Island to Brazil, but I found an article published in the Vineyard Gazette that reports a recent surge in their population on Martha’s Vineyard beaches. Local wildlife biologists speculate that climate change may be responsible for the crab’s expanding range. Their growing population coupled with the crab’s aggressive nature might mean that the Vineyard’s nesting piping plovers (a threatened and even endangered species in some states) are contending with an additional predator. Ghost crabs eat plover eggs and have been observed chasing the chicks.

Ghost Crabs burrow in the sand and are generally terrestrial, heading to the water to wet their gills, and for females, to keep their eggs moist. According to an article on the Chesapeake Bay Program’s website, Ghost Crabs can rotate their long-stalked eyes 360 degrees! They can also make three sounds by either striking the ground with their claws, rubbing their legs together or emitting a bubbling sound.

The dead Ghost Crab found by that student is drying out on my deck. I’m hoping a hungry raccoon doesn’t snatch it away, as I’d like to add this fascinating crab to our educator’s specimen collection.