Makes the Dinosaurs Look Like Infants

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Atlantic Horseshoe Crab

Limulus polyphemus[i]

Horseshoe crabs. These things have been around forever. Just about anyway. Exactly how long have they been around? About 450 million years,[ii] which is a pretty fucking long time. Just to give you an idea of how long that is, it is almost twice as long as the oldest known dinosaur, and they appeared a little over 230 million years ago.[iii] The dinosaurs (not including birds, but I will get into that in some other post) are long gone, and yet those horseshoe crabs are still kicking, so I guess they are doing something right.

They were once thought to be crustaceans like lobsters and crabs, but are actually more closely related to arachnids than anything.[iv] In fact, if you flip a horseshoe crab over and look at its belly, it actually does look kinda spidery.  Also, horseshoe crabs are more closely related to the ancient trilobite than anything else living today.[v] And like their ancient kin, these guys look totally prehistoric.

In order to grow, the need to shed their exoskeletons, which they do several times in their life.[vi] Before they shed their exoskeletons (also known as molting) they will head to the edges of a tidal flat and bury themselves for protection.[vii] And when they do molt, they grow by as much as 25 to 30%.[viii] The body mass was already there, it is just that their exoskeleton was getting too tight. The molts are frequently mistaken for dead horseshoe crabs, however you can tell the difference first by looking for a seam in the front of the exoskeleton, a pale color to the molt, as well as not finding a nasty dead rotting shellfish odor.[ix] Also dead horseshoe crabs will attract a lot of seagulls,[x]  whom apparently find rotting things on the beach to be quite tasty. Horseshoe crabs also tend to molt at about the exact same time and as a result, shortly afterwards the beach will be covered with their molts.[xi] I encountered this once in Hyannis and there were horseshoe crab shells were all over the beach. At first, I thought there was something wrong, but was later informed that this is completely normal. They stop molting when they reach adulthood,[xii] and the female can grow up to two feet in length – which is about 25 to 30% larger than the male.[xiii]

There are four species of horseshoe crab,[xiv] and only one lives in New England: The Atlantic Horseshoe Crab.[xv] The other three are found in Asia,[xvi] and they won’t be covered in this post. As for the one species found here, they can be found in coastal areas all across the region.[xvii]

These guys are of major economic importance. They are harvested for bait for eels, whelk and conch.[xviii] And because of this they have been overfished.[xix] They have also suffered some habitat loss,[xx] which has also affected their numbers, which overall have been in decline,[xxi] especially here in New England,[xxii] though in other areas they are doing much better. There is also an ecotourism industry around these guys creating a bunch of jobs. Apparently people like looking at them[xxiii], but then again in all fairness they are quite unusual. And then there is the medicinal aspects to this animal, more about that below.

When the Spanish conquistadors arrived in Florida, they named a bay after them which is now called Cockroach Bay because they somehow thought these things were giant cockroaches and they lived in huge numbers there at the time.[xxiv] And when the French arrived to North America in 1604, they brought some back and called them the King Crab,[xxv] probably impressed by their size along with unusual shape. However, don’t confuse them for the king crabs found in restaurants and supermarkets, as these guys contain tetrodoxin,[xxvi] the same stuff found in fugu, and yes that can kill you.[xxvii] The roe however, is edible but reportedly tastes like ass.[xxviii]

Horseshoe crabs are a huge fucking boatload of weird ass shit.  For starters, they swim upside down.[xxix] They also have a crapload of eyes all over their body. They got the two big compound eyes on their prosoma – which is kinda like their head and part of their torso combined[xxx] – plus tiny eyes right next to them, a tiny eye right in the middle of the head, eyes on their bellies and their tail can detect light,[xxxi] though probably not all that well. They can also regrow lost limbs.[xxxii] It is thought that they live to be between 20 and forty years in the wild.[xxxiii] So they live for a pretty damned long time.

There is also some unusual stuff involving horseshoe crabs involving medical research. In 1967, three guys won the Nobel Prize in Medicine for their work in horseshoe crab eyes. Apparently, they used their research to figure out how eyes work.[xxxiv] Another odd thing about them is that they have blue blood, which is based on copper instead of iron.[xxxv] This blood also contains a type of blood cell called an amoebocyte, which the tendency to clot when bacterial endotoxins are present, and because of this it is used to test medical equipment.[xxxvi]

As you may have noticed the horseshoe crab has a long pointy tail, it looks wicked sharp. A lot of people think they use it for hunting or self-defense, but that is not the case. It is actually quite harmless. It is called a “telson” which might be helpful knowledge the next time you play Scrabble, even though it won’t get you that many points. That telson is used to flip itself over when stranded on its back

They start breeding when they are nine years old.[xxxvii] Every year, in late spring and early summer, adult horseshoe crabs all go to the beach to mate and lay their eggs.[xxxviii] Usually they like to mate during the neap tide, which has something to do with the size of sand grains at that particular tide, because they get soaked with seawater a certain amount during each tide.[xxxix] They lay several thousand eggs per season: between 15,000 and 64,000,[xl] and these eggs are a major source for many kinds of shorebirds,[xli] and is a major food source for a bird called the red knot during migration.[xlii] They also prefer to breed often during full moons and at night, but some horseshoe crabs are less fussy and will fuck whenever, [xliii] I guess some of them are just too damned horny and just wanna party like a rock star. When they are done breeding they go back to the deeper waters of the continental shelf until next year.[xliv]

——————————————————————————————————————————————

Damn, this one was a lot of work! So much stuff about horseshoe crabs out there, and there was so much interesting stuff, yet I still left out a lot. Otherwise this would be one hell of a long ass post and would take me about three times as long to write it. Seems there is a lot of interest out there about these critters. And since it is late December I want to wish all you readers out there have a happy Chanukah, Kwanza, Yule, Saturnalia, Festivus or whatever holiday you celebrate this time of year.

[i] Author Unknown “Atlantic Horseshoe Crab” Wikipedia https://en.wikipedia.org/wiki/Atlantic_horseshoe_crab 14DEC2016

[ii] Author Unknown “Horseshoe Crab” Wikipedia https://en.wikipedia.org/wiki/Horseshoe_crab 14DEC2016

[iii] Author Unknown “Dinosaur” Wikipedia https://en.wikipedia.org/wiki/Dinosaur 14DEC2016

[iv] Author Unknown “Horseshoe Crab” Wikipedia https://en.wikipedia.org/wiki/Horseshoe_crab 16DEC2016

[v] Edgecombe, Misty “Horseshoe Crab Remains Mystery to Biologies” Bangor Daily News 2002 via National Geographic News http://news.nationalgeographic.com/news/2002/06/0621_020621_wirehorseshoecrab_2.html

[vi] Author Unknown “Molting” The Horseshoe Crab http://www.horseshoecrab.org/nh/molt.html 2003-2009

[vii] Author Unknown “Molting” The Horseshoe Crab http://www.horseshoecrab.org/nh/molt.html 2003-2009

[viii] Reynolds, Joe “Why so Many ‘Dead’ Horseshoe Crabs on the Beach?” Middletown Patch http://patch.com/new-jersey/middletown-nj/why-so-many-dead-horseshoe-crabs-on-the-beach 22SEP2013

[ix] Reynolds, Joe “Why so Many ‘Dead’ Horseshoe Crabs on the Beach?” Middletown Patch http://patch.com/new-jersey/middletown-nj/why-so-many-dead-horseshoe-crabs-on-the-beach 22SEP2013

[x] Reynolds, Joe “Why so Many ‘Dead’ Horseshoe Crabs on the Beach?” Middletown Patch http://patch.com/new-jersey/middletown-nj/why-so-many-dead-horseshoe-crabs-on-the-beach 22SEP2013

[xi] Reynolds, Joe “Why so Many ‘Dead’ Horseshoe Crabs on the Beach?” Middletown Patch http://patch.com/new-jersey/middletown-nj/why-so-many-dead-horseshoe-crabs-on-the-beach 22SEP2013

[xii] Author Unknown “Lifecycle” The Horseshoe Crab” http://www.horseshoecrab.org/info/lifecycle.html 22DEC2016

[xiii] Author Unknown “Atlantic Horseshoe Crab” Wikipedia https://en.wikipedia.org/wiki/Atlantic_horseshoe_crab 19DEC2016

[xiv] Author Unknown “Horseshoe Crab” Wikipedia https://en.wikipedia.org/wiki/Horseshoe_crab 14DEC2016

[xv] Author Unknown “Atlantic Horseshoe Crab” Wikipedia https://en.wikipedia.org/wiki/Atlantic_horseshoe_crab 14DEC2016

[xvi] Author Unknown “Atlantic Horseshoe Crab” Wikipedia https://en.wikipedia.org/wiki/Atlantic_horseshoe_crab 14DEC2016

[xvii] Author Unknown “Horseshoe Crab” National Wildlife Federation https://www.nwf.org/Wildlife/Wildlife-Library/Invertebrates/Horseshoe-Crab.aspx 1996-2016

[xviii] Author Unknown “Atlantic Horseshoe Crab” Wikipedia https://en.wikipedia.org/wiki/Atlantic_horseshoe_crab 14DEC2016

[xix] Foderaro, Lisa W. “A Bird, A Crab, and a Shared Fight to Survive” New York Times 05JUN2012 http://www.nytimes.com/2012/06/06/nyregion/red-knots-horseshoe-crabs-and-fight-to-survive-in-delaware-bay.html

[xx] Author Unknown “Atlantic Horseshoe Crab” Wikipedia https://en.wikipedia.org/wiki/Atlantic_horseshoe_crab 18DEC2016

[xxi] Author Unknown “Atlantic Horseshoe Crab” Wikipedia https://en.wikipedia.org/wiki/Atlantic_horseshoe_crab 18DEC2016

[xxii] MacAdam, Heather Dune “Horseshoe Crab Count Under Way on East Coast” National Geographic http://news.nationalgeographic.com/news/2014/05/140516-horseshoe-crabs-long-island-blood-coagulant-conch-bait-quadrat-protocol-red-knots-science-world/  Published 17MAY2014

[xxiii] Author Unknown “Conservation” The Horseshoe Crab http://www.horseshoecrab.org/con/con.html 2003-2009

[xxiv] Grant, David “Living on Limulus” The Horseshoe Crab http://www.horseshoecrab.org/info/ecology.html 21DEC2016

[xxv] Grant, David “Living on Limulus” The Horseshoe Crab http://www.horseshoecrab.org/info/ecology.html 21DEC2016

[xxvi] Author Unknown “Horseshoe Crab Should You Eat Horseshoe Crab” How to Cook Crab Legs http://www.crablegshowtocook.com/Eat-Horseshoe-Crab.html 21DEC2016

[xxvii] Author Unknown “Tetrodoxin” Wikipedia https://en.wikipedia.org/wiki/Tetrodotoxin 21DEC2016

[xxviii] Author Unknown “Horseshoe Crab Should You Eat Horseshoe Crab” How to Cook Crab Legs http://www.crablegshowtocook.com/Eat-Horseshoe-Crab.html 21DEC2016

[xxix] Author Unknown “Horseshoe Crab” Wikipedia https://en.wikipedia.org/wiki/Horseshoe_crab 15DEC2016

[xxx] Author Unknown “Horseshoe Crab” Wikipedia https://en.wikipedia.org/wiki/Horseshoe_crab 21DEC2016

[xxxi] Author Unknown “Horseshoe Crab” Wikipedia https://en.wikipedia.org/wiki/Horseshoe_crab 18DEC2016

[xxxii] Author Unknown “Atlantic Horseshoe Crab” Wikipedia https://en.wikipedia.org/wiki/Atlantic_horseshoe_crab 19DEC2016

[xxxiii] Author Unknown “Atlantic Horseshoe Crab” Wikipedia https://en.wikipedia.org/wiki/Atlantic_horseshoe_crab 21DEC2016

[xxxiv] Author Unknown  “Haldan Keffer Hartline” Wikipedia https://en.wikipedia.org/wiki/Haldan_Keffer_Hartline 14DEC2014

[xxxv] Author Unknown “Horseshoe Crab” Wikipedia https://en.wikipedia.org/wiki/Horseshoe_crab 15DEC2016

[xxxvi] Author Unknown “Horseshoe Crab” Wikipedia https://en.wikipedia.org/wiki/Horseshoe_crab 15DEC2016

[xxxvii] Author Unknown “Atlantic Horseshoe Crab” Wikipedia https://en.wikipedia.org/wiki/Atlantic_horseshoe_crab 21DEC2016

[xxxviii] Author Unknown “Lifecycle” The Horseshoe Crab” http://www.horseshoecrab.org/info/lifecycle.html 16DEC2016

[xxxix] Author Unknown “Lifecycle” The Horseshoe Crab” http://www.horseshoecrab.org/info/lifecycle.html 16DEC2016

[xl] Author Unknown “Horseshoe Crab” Wikipedia https://en.wikipedia.org/wiki/Horseshoe_crab 19DEC2016

[xli] Author Unknown “Lifecycle” The Horseshoe Crab” http://www.horseshoecrab.org/info/lifecycle.html 16DEC2016

[xlii] Author Unknown “Atlantic Horseshoe Crab” Wikipedia https://en.wikipedia.org/wiki/Atlantic_horseshoe_crab 19DEC2016

[xliii] Author Unknown “Lifecycle” The Horseshoe Crab” http://www.horseshoecrab.org/info/lifecycle.html 16DEC2016

[xliv] Author Unknown “Atlantic Horseshoe Crab” Wikipedia https://en.wikipedia.org/wiki/Atlantic_horseshoe_crab 16DEC2016

 

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