The family is together for a holiday weekend in Rhode Island. What do we do for entertainment? Crab porn, of course.
Limulus polyphemus, commonly known as the
horseshoe crab, is not really a crab but at all, but rather a
chelicerate arthropod more closely related to spiders and scorpions than crustaceans. Dating from the Paleozoic Era (570-248 million years ago), these "living fossils" have seen the trilobites, the dinosaurs, the mammoths and saber toothed tigers come and go. We humans are, to them, mere blips in evolutionary time. How have they endured so long? By having lots and lots and lots of sex. But how much
exactly? That is the question we sought to answer.
The scene: A New England beach at dusk. As the last wisps of pink fade from the sky, dramatic clouds pulsate with the flash of distant lightning, sending
frissons of romance across the sand and pebbles.
The team: A crack-crew of world-renown oceanographers armed with the most sophisticated equipment.
The task: Conduct the first-ever survey of
limulus in the area on this, the night of the full moon, when the high tides send the creatures into a literal MATING FRENZY. Danger is high, but Science, and Glory, command us on.
We arrive at the scene to a rude shock--a man dragging a full and heavy sack down the beach.We ask him what he is collecting. Horseshoe crabs, he replies. Sure enough, a glimpse inside the sack reveals four large specimens. We are here to survey them, mom tells the poacher. An awkward silence follows. We decide to begin the survey on the opposite side of the beach.
The blood of horseshoe crabs has an interesting property that makes them valuable detectors of infection. The blood of a single crab, extracted over its lifetime, can be worth up to $10,000. This value has put pressure on the crab population, but no one really knows how much. Hence the need for the survey we are conducting.
And our efforts are not in vain. Using advanced rope-and-stick technology, we divide the tidal zone into quadrants and search for breeding pairs.

Sure enough, all over the beach the crabs are doing it with the efficiency only 450 million years of evolution can generate (sensitive viewers should skip the next images).


Hot.
After counting the copulating crabs, we then set about tagging a few of them to evaluate their migratory behavior. This is the most dangerous part of the job.
Fortunately, the team is well trained and fearless, nimbly seizing the crabs before they can stab us with their deadly tail spikes (or something like that).




In the end, some 12 crabs were counted, including six in the act itself. Two were tagged. One poacher was turned back.
Though utlimately beaten back by the increasingly close and intense lightning storm, the team felt a considerable amount of pride after completing the survey.

Most importantly, rigorous scientific prodcuedres were followed at all times.