The spawning of horseshoe crabs is a ritual dating back to prehistoric times and, like the euphemism about the birds and the bees, their mating behavior also signals the arrival of spring.
Described by the Washington Post as “one of nature's longest-running — and oddest-looking — spring flings,” horseshoe crabs are making their way to shore and getting down to the age-old business of reproduction.
Because the animals are so vital to the environment, they're being monitored closely by scientists during mating season, according to a statement from Kelly Richmond of the Florida Fish and Wildlife Conservation Commission.
“Horseshoe crabs, often called living fossils, are an important part of the marine ecosystem,” she said. “Their eggs are a food source for animals. Birds, such as red knots, rely on horseshoe crab eggs to fuel their long migrations to nesting grounds.” Some fish species feast on the eggs, too.
Horseshoe crabs also are valuable to the medical world. Pharmaceutical companies use horseshoe crab blood to ensure that intravenous drugs and vaccine injections are bacteria-free and sterile. Scientists also are using horseshoe crabs in cancer research.
Each spring, large numbers of the tank-like creatures — which aren't crabs at all but are closely related to scorpions, spiders and ticks — move onto sandy beaches to mate and lay eggs. The ideal habitat generally includes coastal areas, bays and coves that are protected from significant wave action.
The horseshoe crab has a hard shell that looks like a flattened Army helmet, with 10 hairy legs beneath it and a long, spiny-looking tail they use to right themselves when flipped over by a wave. They're harmless to people and prey on clams, crustaceans, worms and other animals and even algae.
Beachgoers likely will have the best luck spotting amorous horseshoe crabs around high tide, just before, during or after a new or full moon.
The next two new moons are Sunday and April 29. The full moon will appear next on April 15 and again on May 14.
The state is asking for the public's help in identifying and collecting basic information about horseshoe crabs. Observers should count the crabs they see, note whether the creatures appear to be mating and, if possible, tally the number of juveniles. The young ones typically are four inches wide or smaller.
In addition, onlookers are asked to document the date, time, location and environmental conditions — such as tides and moon phases — of their sightings.
To report horseshoe crab activity, fill out an online survey at http://tinyurl.com/luv8epr; send an e-mail to horseshoe@MyFWC.com; or call (866) 252-9326.
The FWC survey program began in April 2002. As of last year, 2,831 reports from across the state had been submitted. For more on horseshoe crabs, visit http://tinyurl.com/kwf4xun.