Natural History

Horseshoe Crab

posted: 05/23/13
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Horseshoe Crab | Photo Caption: Excerpted from North America: A World in One Continent by Huw Cordey

The horseshoe crab is the oldest animal on the planet, a living fossil unchanged for 450 million years. With ten legs, two complex eyes and several simple ones, and a tail that acts like a rudder, it's a strange looking creature. Like crabs, it's an anthropod but horseshoe crabs are most closely related to spiders and scorpions.

The largest concentration of these ancient creatures can be found on the northeast seaboard of the U.S. Females produce about 80,000 eggs a year, and once they are fertilized she buries around 4,000 to 5,000 in the sand. Eventually there are more than one million miniature crabs growing beneath every square foot of beach.

How has this fascinating creature survived unchanged for so long? With these three special features: first, its hard, curved shell makes it a difficult target for predators; second, it can survive for up to a year without food; and third, it can withstand extreme temperatures.

EXPLORE THE SAVAGE COASTS: Lion's Mane Jellyfish | Manatee | Killer Whale | Olive Ridley Sea Turtle | Bottlenose Dolphin | Horseshoe Crab | Peregrine Falcon | Spinner Shark | Gray Whale | Moon Jellyfish | All North American Animals

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