Sunday, January 6, 2013

Hey, Where's the Rest of that Horseshoe Crab?

By B

Hi friends, are you ready to talk about horseshoe crabs? Good!

Horseshoe Crab Molt
Found in Bonner Park, Largo, FL

Lately I've been finding lots of what I thought were small dead horseshoe crabs. I wondered what was killing them. Then I noticed these horseshoe crabs don't weigh very much. I did a little reading (and asked my mom) and found out that these aren't really horseshoe crabs – they are just their exoskeletons!

(I love the word exoskeleton. We used to find lots of cicada exoskeletons when we lived in Kentucky.)

Things with hard shells can't grow as long as that shell is there. So they have to molt, or get rid of their shell for a while so they can get bigger. What a relief! I'm glad they weren't all dead. Plus the shed shells smell much better than dead crabs when you save them for your collection.

I hope you enjoyed this story about horseshoe crabs. Bye until next time!

Horseshoe Crab Facts from Lu:

*Horseshoe crabs are arthropods, a group that includes insects, spiders and crabs.
*They aren't really crabs – they're more closely related to spiders and scorpions.
*When horseshoe crabs are in love, they pair up and go to very shallow water (the intertidal region, between high and low tide) and the female lays up to 120,000 eggs. It is thought that, like sea turtles, they return to the same beach where they were born to lay their eggs.
*Horseshoe crabs have blue blood!
*Young horseshoe crabs molt several times a year, while older ones usually molt only once each year, usually in summer. (Which is probably why B was finding smaller molts this winter... though since this is Florida, some seasonal things are skewed, and I'd guess you can find adult sheds year-round.)

Save a Horseshoe Crab!

Horseshoe crab numbers are declining, for several reasons. Habitat loss is a biggie. They are also used as bait for whelk and eel traps, and their unique blood is harvested for medical use. (They are usually released after blood draw, but the mortality rate is still as high as 15% in some cases.)

Many will also die during mating season when they are flipped on their backs as the tide is going out. In the water they can usually right themselves, but on land they'll die of exposure unless you help. Save a horseshoe crab's life by simply flipping her (or him) back over. They are absolutely harmless – they don't bite or pinch. Don't pick them up by their tail, which is deceptively fragile. Just grasp them by the side of the shell, turn them over and help save the species.

You can also help by reporting signs of spawning to the Florida Horseshoe Crab Survey of the Florida Fish and Wildlife Conservation Commission. If you see two horseshoe crabs in love (as B and I put it) let them know!
(Florida horseshoe crabs can mate year-round, but mostly in spring. I'll try to remind you again around then.)


  1. Very interesting. I wonder why they are called, "Horseshoe crabs" when they look nothing like a horseshoe B?

    1. Hi Daddy!
      I think they do look like horseshoes!

  2. Hi from Japan, dear B! In Japan, they are called "Kabuto-Gani". Kabuto means samurai's helmet! So, they're Helmet-Crab! :D

    I always enjoy reading your lovely stories. Keep writing!

    your new friend, Kyoko (^-^)

    1. Hello Kyoko!
      Thank you for reading!
      Now I will always think of them as samurai crabs. They look so fierce! I read about samurais in a Magic Treehouse book.

  3. What an awesome connection from Japan! I like samurai crabs better!

  4. How come Danny's hands didn't receive a credit?