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Watch Your Step!

Posted by
Steven (Chicagoland, United States) on 29 January 2020 in Animal & Insect and Portfolio.

Horseshoe crabs have been around for more than 300 million years, making them even older than dinosaurs. They look like prehistoric crabs, but are actually more closely related to scorpions and spiders. The horseshoe crab has a hard exoskeleton and 10 legs, which it uses for walking along the seafloor.

The body of the horseshoe crab is divided into three sections. The first section is the prosoma, or head. The name “horseshoe crab” originates from the rounded shape of the head, because just like the shoe on a horse’s foot, the head is round and U-shaped. It's the largest part of the body and contains much of the nervous and biological organs. The head has the brain, heart, mouth, nervous system, and glands—all protected by a large plate. The head also protects the largest set of eyes. Horseshoe crabs have nine eyes scattered throughout the body and several more light receptors near the tail. The two largest eyes are compound and useful for finding mates. The other eyes and light receptors are useful for determining movement and changes in moonlight.

The middle section of the body is the abdomen, or opisthosoma. It looks like a triangle with spines on the sides and a ridge in the center. The spines are movable and help protect the horseshoe crab. On the underside of the abdomen are muscles, used for movement, and gills for breathing.

The third section, the horseshoe crab’s tail, is called the telson. It's long and pointed, and although it looks intimidating, it is not dangerous, poisonous, or used to sting. Horseshoe crabs use the telson to flip themselves over if they happen to be pushed on their backs.

Photo captured October 8, 2019.

NIKON D7000 1/180 second F/6.7 ISO 200 52 mm

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By Marie from Entre By Marie et Montagnes, France

Very original crab I think I have not seen. Beautiful photo Steven

29 Jan 2020 5:23am

Ralf Kesper from Fröndenberg, Germany

Wonderful old living fossile.

29 Jan 2020 5:52am

Martine Girard from Brest, France

Très surprenant.

29 Jan 2020 6:05am

Ginnie Hart from Netherlands

Unbelievable, Steven, when you read about it like this. Lucky you to have found such a perfect specimen!

29 Jan 2020 6:09am

Jypyä Pop from Turku, Finland

Interesting animal. Thanks for the thorough description

29 Jan 2020 6:20am

yoshimiparis from France

in our climates in France we don't have that kind of crab

29 Jan 2020 6:31am

jpla from St Barthélémy, France

Une jolie découverte pour moi

29 Jan 2020 7:43am

Claudine/canelle from Lorient, France

Bravo pour la photo et explication , je n'en ai pas vu beaucoup ..

29 Jan 2020 7:57am

Pascale MD from Occitanie, France

Un animal vraiment surprenant qui a su passer les siècles.
Bonne journée Steven

29 Jan 2020 8:02am

Hiro from Kyoto, Japan

Wow, great find !

29 Jan 2020 9:24am

Existence Artistique from Angers, France

bien cette carapace

29 Jan 2020 9:25am

Le Krop from Charenton-le-Pont, France

Presque abstrait. Tableau ! C'est beau.

29 Jan 2020 9:26am

Shaun from Massachusetts, United States

Excellent look at the Horseshoe crab Steven.

29 Jan 2020 9:42am

Libouton Martine from Bousval, Belgium

Impressionnant !

29 Jan 2020 9:50am

Libouton Martine from Bousval, Belgium

Impressionnant !

29 Jan 2020 9:50am

Anne from France


29 Jan 2020 10:04am

Mhelene from Villiers-sur-Marne, France

Superb photo of the Horseshoe crab !! Never seen !

29 Jan 2020 10:38am