Horseshoe crab Facts

Horseshoe crab Facts
Horseshoe crab is a type of marine arthropod. Despite its name, horseshoe crab is not a crab (it shares more similarities with spiders and scorpions than with crabs). There are 4 species of horseshoe crab: one in the North America and three in the southeast Asia. Horseshoe crabs live on the muddy flats and sandy bottoms in the shallow coastal waters. They haven't changed much for the past 445 million years (since the time they appeared on the planet), hence the nickname "living fossils". Habitat destruction and uncontrolled collecting from the ocean led to drastic reduction in the number of horseshoe crabs in the previous century. These creatures are classified as near threatened today.
Interesting Horseshoe crab Facts:
Horseshoe crab can reach 8 to 24 inches in length and 2.2 to 9.9 pounds of weight. Females are much larger than males.
Horseshoe crab has hard outer shell, called carapace, shaped like a horseshoe. It is green or brown colored. Horseshoe crab has five pairs of legs and long tail. First pair of legs is shaped like pincers and used for feeding. Thin plates on the abdomen, called book gills, are used for breathing.
Horseshoe crab has large compound eyes on the sides of carapace, five eyes on top of the body and two eyes on the bottom side. They are used to facilitate detection of mating partners and navigation in the ocean.
Horseshoe crab has long, rigid tail that is used as a rudder and to rotate animal from the back to the feet when it flips over.
Horseshoe crab has blue blood due to hemocyanin, blood pigment which contains copper. Its blood also contains amoebocytes (type of blood cells) that are used in numerous laboratories today for testing of sterility of medical equipment and drugs.
Adult horseshoe crabs walk on the sea floor. Young animals occasionally swim oriented upside down by using gills as paddles.
Horseshoe crab is nocturnal creature.
Horseshoe crab is a carnivore. It likes to eat aquatic worms, algae, clams and mussels.
Horseshoe crab uses upper parts of its legs to crush food before swallowing.
Mating season of horseshoe crabs takes place during the May and June.
Females dig holes in the sand and deposit eggs. They produce 60.000 to 120.000 eggs per season. Only 10% of eggs hatch and reach adulthood due to numerous predators.
Many migratory birds land on the shore to consume eggs and crabs on their ways to the wintering grounds. Eggs of horseshoe crab also represent important source of food for fish and sea turtles.
Larvae emerge from the nest usually after 5 weeks. They look like miniature version of adults with very short tail.
Males reach sexual maturity at the age of 8 to 9 years, females at the age of 10 to 11 years.
Horseshoe crab can survive 20 to 40 years in the wild.

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