BOO!!
If you follow us on Instagram, then you’ve seen that for the month of October we featured an especially spooky specimen in all of our pictures. As today is Halloween, I think we are all a little more aware of things that… shall we say… go bump in the night? One of those things is our friend, the ghost crab. Covering sandy shores from the Atlantic to the Indo-Pacific, these creepy crustaceans blend in with their environment when they emerge from their burrows in the dead of night. In our collection we have more than 50 ghost crab specimens belonging to 3 different species. Each more spooky than the last…
To really understand why we chose to feature the ghost crab for Spooktober, we should first talk about what makes them unique. Ghost crabs belong to a small group within the Order Decapoda (5 pairs of legs) and the Family Ocypodidae. This family contains two major groups of crabs- fiddler crabs and ghost crabs meaning these little guys are pretty closely related but not exactly the same. One difference between these two groups is that both male and female ghost crabs have one enlarged claw while only male fiddler crabs display this trait- and their enlarged extremity is significantly larger than that of a male ghost crab. These little guys are semi-terrestrial so they spend some time in the water soaking their gills, and the rest of their time on land haunting night beach walkers who dare to disturb them…
In the interest of full transparency, we have to admit that ghost crabs aren’t actually very scary critters. To be honest, they are pretty cute little fellas. Their name comes from their (super)natural abilities. Ghost crabs have evolved to alter their coloration slightly to match their environment and time of day, and they can run up to 10 mph. These qualities make them difficult to spot (think Casper the friendly ghost). They are also nocturnal which means they are more active at night (in case you’ve never heard of an owl or bat- other spooky creatures). If you’ve ever taken a stroll along the beaches of the Atlantic coast and seen holes with piles of sand next to them and teeny tiny foot prints, you are likely staring at the home of a ghost crab. These burrows can be anywhere from 2 to 4 feet deep and are usually only home to one ghost crab at a time. Similar to Freddy Krueger, they don’t make good roommates. Sand dispersal patterns outside of ghost crab burrows may be related to courtship behaviors. These haunted burrows can be found anywhere from the high tide line to the dunes and in some cases have an emergency exit in addition to the front door (not a bad idea on nights like tonight).
While their name made them a perfect candidate for our All Hallows’ Eve Creature Feature, these little guys are well-deserving of the spotlight for multiple reasons. Ghost crabs are commonly used as indicators of human activity on beach fronts. In places like North Carolina and South Carolina where the beaches and the tourism they bring mean a great deal to our economy, measuring human activity is crucial. Unfortunately, this means that the more human activity, the more likely it is that ghost crab burrows are being destroyed and ghost crab populations are on the decline. There have been some efforts to protect this small group of crustaceans, but as they are predators and don’t bring nearly as much money to our economy as tourists do, these conservation efforts aren’t high on many people’s lists. Conservation efforts directed at other species can sometimes harm ghost crabs even more. They prey on things like turtle eggs which are highly protected in some areas. In those situations, ghost crab burrows are destroyed to keep them away from turtle nests. And ghost crab “hunting” is really more of a family pastime during night time strolls along the beach than a source of income. On the rare occasion that these ghoulish little guys are benefiting from human intervention, they are likely just indirectly benefiting from efforts to protect the coast for other reasons.
Another reason they deserved the spotlight this month is because of their fascinating eyes. Their eye stalks are very tall, even by crustacean standards. Typically, their eye stalks are longer than the space between them and they allow them to see 360°. So the next time you are taking your romantic midnight stroll along the beach, just remember…the ghost crabs are watching you.
Written by Andie Woodson.
Thanks for joining us for this Special Spooky Creature Feature! If you would like to follow the everyday adventures of our lab, check us out on Twitter and Instagram at @BWWilliamsLab. We hope you enjoyed learning about the ghosts of the coast as much as we did. If so, please share it with your friends and let us know in the comments! Signed, the NMI Lab.
Sources
https://animaldiversity.org/accounts/Ocypode/classification/
http://txmarspecies.tamug.edu/invertfamilydetails.cfm?famnameID=Ocypodidae
http://eol.org/pages/313161/details
https://en.wikipedia.org/wiki/Ghost_crab
http://www.dnr.sc.gov/cwcs/pdf/Ghostcrab.pdf
For more awesome information about Ghost Crabs, check out this blog from our friend Tony Martin!