Friday, January 19, 2018

Seen a Limulus Lately?

February 1, 2015 by · Leave a Comment 

limulus 1

What has 10 legs, blue blood, and predates the dinosaurs? No, it’s not a vampire super-hero, so let’s try another hint: You’ll find it crawling on our beaches in the summer.

If you guess the creature is some kind of spider, you’re not far off.  It’s sometimes called a sea spider, but we usually refer to it as the horseshoe crab! (I put the crab’s Latin name in the title to this story so you’d have to guess a bit.)

It’s called horseshoe because of the shape of its hard shell covering all those legs as well as hundreds of little muscles. The tail that sticks out the back of the shell acts as a rudder to guide the crab, somewhat like the rudder on our boats.

In the spring, a female horseshoe crab lays up to 80,000 eggs in the sand by the water line. Hungry migrating birds feed on many of them, but enough eggs survive to produce big families of horseshoe crabs. Like snakes, horseshoe crabs molt (change skin). Once all those legs and muscles outgrow that hard shell, they have to drop it to make way for the next one growing underneath. Young crabs molt several times during the first year of life.

Since the horseshoe crabs have been around for so long, we want to keep them safe.  Some of us take part in counting local ones each year, tagging some to see how far they go. One year, a horseshoe crab tagged in Northport was found in Coney Island!

If you ever spot an upside down horseshoe crab, carefully turn it over and put it back in the water. The crab should not harm you if you handle it with care, and you will have saved one of our most interesting creatures.

By Ann Fox

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