The horseshoe crab is a hard-shelled invertebrate found on the sea floor in warmer climates. Despite it's name, the horseshoe crab is not actually a crab (or crustacean) and is in fact more closely related to arachnids such as spiders and scorpions.
There are four different species of horseshoe crab found inhabiting the
warmer shallows off the coasts of India, Japan, Indonesia, the eastern
USA, and the Gulf of Mexico.
The horseshoe crab has a hard outer shell, five pairs of legs and a long, thin tail which the horseshoe crab uses for changing direction whilst swimming rather than as a defensive weapon.
The appearance of the horseshoe crab is thought to have changed very
little from when it first evolved around 500 million years ago.
Horseshoe crabs breathe using book gills, which are thin plates found on
the abdomen of the horseshoe crab.
Horseshoe crabs are generally nocturnal animals, coming out of the shadows in the darkness in order to hunt for food. As carnivorous animals,
horseshoe crabs only eat meat including sea worms, small molluscs and
crustaceans. Thanks to their armoured casing, horseshoe crabs have few
natural predators and are primarily hunted by sharks and sea turtles.
Humans also widely hunt the horseshoe crab around the world, along with
coastal birds that pick the horseshoe crabs out of the shallows.
Female horseshoe crabs are known to lay between 60,000 to 120,000 eggs at a time. After mating, the female horseshoe crab lays her eggs into a hole in the sand which she then covers up to protect them. Today, the horseshoe crab
is still found widely along the world's warmer coastlines although
horseshoe crab populations in certain areas are suffering from high
levels of water pollution and over-fishing. Source
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