Horseshoe Crab Anatomy

hi I'm Kris Oakley here at the aquarium of Alabama I'm one of our players I'm here today with dr. Ruth Carmichael to talk about horseshoe crabs in honor of international horseshoe crab day here at our ray tank here hey welcome thank you everybody for joining us for international horseshoe crab day and we just thought we'd spend a little bit of time introducing you to horseshoe crabs and we've got a male and a female here that we want to show you if you want to just look at the overall structure of the horseshoe crab the main parts of the body are the head which is also called the per soma and the abdomen the back part which is called the Epistle OMA and the tail or the telson and some of the cool features of horseshoe crabs if you look right on they have a really cool compound eye that you guys might be able to get a good look at they're very often horseshoe crabs are covered with other kinds of organisms that live on the surface and we'll see that in a minute when we pull out the mail but this female is she's pretty clean and pretty slick horseshoe crabs have a really amazing immune system so they're able to fight off a lot of types of diseases and infections and actually their blood is used as the gold standard for testing all medical supplies and equipment that we use so if you've ever had an injection for example of a drug or you've ever had stitches any of those products were tested with horseshoe crab blood to make sure that it's safe to be used on humans so they're really really important to us and if you want to look right here at the hinge area that's actually right under there is the heart which is where they take the blood that's actually used to make the compounds that are important for protecting people so we're gonna go ahead and turn this girl over and now we're looking at the underside of her and you guys will notice that I'm holding her by her head or her purse oma and that's the best way to hold a horseshoe crab you don't want to pick him up by the tail because you can really hurt them if you pick them up by the tail but you all them like this and you can really get a good look underneath so what we're looking at is all of her legs and she's got some walking legs but she'll also know that she's got these really cool-looking pusher feet and these kind of look like flowers and those are used for pushing and digging into the sand because they will bury themselves for example to build nests when they want to lay their eggs in the sand and right in here in the middle at the base of the lakes these are called the NASA bases because they're used for actually chewing and that's the mouth inside and so you can see they're really kind of hairy all those hairs have a lot of sensors on them that are used it's like a big tongue and then they'll rub those legs together at the base to pull in food into kind of macerate food or grind it up a little bit as they're eating so they'll pull it right in there but she's all clean so you can see all of her hairs and everything so cool I will go ahead and see if she wants to take a little bit of it's a weird way to eat but we'll see if she wants to take a little food in if she smells it and decides to take it in and if you look just behind the legs she's kind of curled up on us now this is a defensive maneuver that crabs do if you look behind the legs you'll see all of these little folds here underneath there is where she has her gills oh look at that she's taking the food in good girl like a little vacuum cleaner out in the wild these animals will eat any kind of thing that's in the sand they sort of act like little vacuum cleaners so as they burrow through the sand they'll actually take in their food but they'll also take in the sand itself and they'll kind of clean particles from the sand and then when they release their feces they sort of are releasing that that clean sand it's been cleaned of all the organics all right so let's look underneath and see we can get a good look at her gills under here so the gills are how they breathe and if we just look under this these flaps she may not want to show us today the first flap I also want to be gentle so we don't hurt her at all the first flap is actually where they have their reproductive parts so if you can see those two slits down there that's actually how we know a male from a female because the female has these broad slits to release eggs and a male has little points where he will release his sperm or Milt and sew hers right there her two little slits where she releases eggs and then behind that these are called the book gills and I'm going to put her in the water and see if she'll flap her gills a little bit sometimes she will but if we open these up a little bit you'll be able to see all the little flaps underneath there we go all those little flaps are the gills that they use for breathing so they're all underneath here and then last but not least right under the tail here guess what that is yes what's beneath the tail that's where the lease comes out right that's the anus very good all right go ahead and flip her back over a couple of other things to notice on the female now this is a young female so she doesn't have a lot of mating scars but the males will clasp on to the back of the female you can kind of see these two little Mark's here and I'll show you the claspers on the male in just a minute but the male will clasp on and hold on to the female for mating and socially usually get some scars along here where his shell has rubbed into her shell and you'll also I want you to notice the front of the female is fairly flat in the front there's not much of an arch and so we'll contrast that to the male in just a second all right we would you bring him out seeing as there are males been through a little bit can I swap out with you thanks he's been through a few things here but one of this is actually you can see this better in the water he's got algae growing all over the surface and that's pretty common especially as the crabs get a little bit older their shells normally produce what's called an egg zu date which is a slick substance that is sort of an anti fouling substance but that decreases as they get older so they'll often especially if they're kept in in aquaria they may get some algae like this on the surface or they may get barnacles or other kinds of animals that live on and that's pretty common there's actually a book even entitled living on Limulus all about the creatures that live on horseshoe crabs and use horseshoe crabs for habitat so you can see he's all got the same parts as the female well we're gonna flip him over and notice actually notice his the front of his shell see how big that arch is compared to the females and that's so that he can accommodate her body when they're mating so if we compare him to the female do you have her alright I just want to show how this would work so in mating the mill will actually am Plex or hook on to the female this way and so he has that higher persona arch to accommodate her back and then he'll hook on he's got special front leg so he knows we flip him over he looks just like her except his front legs instead of being all pincers like hers see how these are pincers his front legs are these little boxer claws and these little boxer claws are especially modified he doesn't like me they're especially modified to grab on to that female shell during mating they look like little fists right and then he's also got the same pusher feet behind and the same Gill setup and let's see if we can get him to show us a little bit there we go now let's look under his flap see if we can see those reactional turn around see if we can see those reproductive structures a little bit better see where the female had the broad slits he's got points so that's our introduction to basic horseshoe crab anatomy and we really appreciate you guys tuning in to take a look at our crabs today and we'll see you in another video shortly to talk a little bit about how these animals grow and molt so come back and 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Channel: Dauphin Island Sea Lab

Views: 12,962

Rating: 4.9056048 out of 5

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Id: rmlOAlodt54

Length: 8min 16sec (496 seconds)

Published: Fri Jun 19 2020