In Its Time, The Sea Will Come To You

Two years ago we vacationed on the shore in Delaware, staying in a dune-hugger cottage on a narrow spit of sand between the bay and an expansive estuary.  It was quiet, few other cottages, and fewer still other vacationers.  The wildlife was the draw for us, the abundance of birds was astounding.
This summer we're returning to Delaware, this time staying in Broadkill Beach, which is much more popular than Prime Hook, where we stayed last time.  It's impossible to be at the beach, at least for me, and not think of sea-level rise and what this means for communities on this shifting front line.  Depending on how quickly the glaciers of Antarctica and Greenland continue to melt, nearly all of the seaside towns on the Delaware Bay will be under water.  This will effect man much more than nature, as I believe that the wildlife will simply adapt, and the terrain is in a constant state of flux regardless.  It lends a sort of bitter sweetness to the experience, being in a place that can't remain.

Desiccation is a Beach

Horseshoe Crab, Limulus polyphemus, Delaware Bay, DE, 2014


I didn't have much interest in the horseshoe crab before we spent a week on the beach in Delaware and were surrounded by them.  Curiosity got the best of me, as it almost always does, and lucky for me that our cottage rental had several books on the local flora, fauna, and even covered the geology of the region.
Above are two female horseshoe crabs, dorsal and ventral views.  The exposed pincers on the left specimen are what gives away the sex.  When sexing a horseshoe crab you simply turn them over and and look at the first set of pincers.  If they're pincer-like in appearance, then it's a female.  If they look like tiny boxing gloves, then it's a male.  The boxing glove-like appendage aids the male in mounting and holding on to the larger female.
While walking the beach we discovered many small, desiccated remains of horseshoe craps, and I brought a few home with me in a shoe box.  I should've paid closer attention because all of the specimens I gathered were female.  I'd based which ones to take on the condition of the remains, so that's my only excuse.
We're returning to the beach in Delaware this summer.  With luck I'll find a good example of a dead male horseshoe crab that's in one piece.

Sex On The Beach

Horseshoe Crabs Mating, Prime Hook Beach, DE, 2014

Horseshoe crabs are often referred to as 'living fossils', having emerged during the Paleozoic Era, 540 million years ago.  Not many creatures survive eon after eon, so there's got to be something advantageous about their method of reproduction.  The male, who is smaller than the female (common among arthropods), mounts the female and she digs a hole in the sand where she deposits several thousand eggs at a time, and then he releases his sperm over them.  While shore birds consume many of the eggs, enough survive to continue the species.