Mesozoic Mystery Tour; June 1998; Scientific American Magazine; by Zorpette; 2 Page(s)
Flatlands, Brooklyn, is not the kind of place to which one generally travels to reflect, awestruck, on an indescribably ancient natural pageant. But this is exactly what I did last year, on a breezy evening when the moon was full, and the summer solstice was only a day away.
Every year horseshoe crabs and their evolutionary ancestors have crawled shoreward in a mating ritual that is perhaps 400 million years old. The procession starts out on the continental shelves, where the creatures subsist on mussels, worms and other bottom dwellers. Once during their lives, in spring or early summer, the females trek in to shore to lay in the intertidal region. The coupling is best viewed during the unusually high tides of a full or new moon, when the females creep to the edge of the waterline, each with a male clinging to her posterior in the tenacious copulative embrace known as amplexus. In Florida the migration peaks in March and April; in Delaware Bay the traffic is usually heaviest around April and May; in the northeast U.S., June and July is generally the best time to view the spectacle.