Look out for mating crabs on South Carolina beaches, officials say. Here’s why

Do you think moonlit beaches are romantic? Watch your step, because so do horseshoe crabs.

Spawning season has arrived for the blue-blooded arthropods, and South Carolina wildlife officials are asking people to keep an eye out for them — for research purposes.

Horseshoe crabs prefer to keep underwater, McClatchy News reported, but every year in spring and summer they emerge from the sea, huddle close together on beaches, and carry out the important business of laying and fertilizing eggs.

“It’s a huge spring orgy,” a Beaufort fisherman told McClatchy.

They often do this at night, and they’ve been doing it for at least 445 million years.

Witness anything like that recently? The state Department of Natural Resources wants you to report it.

“Help be our eyes and ears on the beach,” SCDNR said in a Facebook post Friday, along with a video showing the kinds of horseshoe crab formations to look out for, ranging from clusters to conga lines.

While groups can be large in size, they don’t have to be. Any time two or more horseshoe crabs are spotted on the beach during spawning season, near enough that they’re touching, odds are good they’re trying to reproduce, according to wildlife officials.

“If you see groups of horseshoe crabs like this, please report their location to us.”

Department biologists are trying to track the spots where horseshoe crabs come ashore to lay their eggs, according to SCDNR.

The department has created an online reporting document, with questions like the number of crabs spotted, the time of day, and GPS coordinates of the breeding site.

“Your data will help us better understand these amazing animals and make informed decisions about our shared natural shorelines,” the document says.