I agree the horseshoe crab is quite possibly the scariest looking creature along the shoreline. However, what makes this animal so amazing it that underneath that tough pointy chitin exoskeleton is a sweetheart of an animal. The horseshoe has survived since before the time of the dinosaurs and it is primarily due to the amazing ability to adapt to all conditions (Darwin – ring a bell?).

The shells that you may see washed up along the coast line are probably molts. The horseshoe crabs have to shed their exoskeleton just like any other crustacean. They grow on average a quarter the size each time they shed – until a certain point of course. Females grow to be approximately two feet across and males and a bit smaller (that helps for the for reproductive reasons).

The pointy tail (telson) is not going to sting you at all. It is what helps the animal turn itself over when the ocean flips it a bit. For ten months out of the year horseshoe crabs live in the depths of the ocean floor. They are most often seen coming to the shore in May and June.

Image (c) FreeFoto.com

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  1. Bernard Sypniewski

    Scary-shmary. I think that they are kinds cute. Are they related to trilobites (or any other kind of bytes)?

  2. Biitz

    wow, ok I spent a REALLY long time last night trying to figure out what these things were. They’ve been washing up on our beach like crazy after the storm we had last week. Thanks for helping me ID them. :D

  1. 1 Beach Chair Scientists and Beyond at Cephalopodcast

    [...] the science behind life in the ocean or along the seashore.” So far there are entries on horseshoe crabs, seaweed and ocean [...]

  2. 2 Are horseshoe crab dangerous? « Beach Chair Scientist

    [...] 23, 2009 in Ocean No. I mentioned in the very first BCS blog entry that the horseshoe crab is a “sweetheart of an animal” and I will continue to defend [...]




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