Crab Amazing facts

35 Amazing and Interesting Facts about Crabs | Amazing Facts 4U 

  1. Both crabs and lobsters are decapods, or crustaceans with 10 limbs. Other decapods include crayfish, prawns, and shrimp.
  2. While lobsters have a long, segmented abdomen that sticks out at the back of their bodies, crabs have a similar but smaller abdomen that is curled up underneath the main shell. A crab’s shell is really a skeleton on the outside of its body. Insects and spiders also have external skeletons.
  3. Most crabs have flat bodies that enable them to squeeze into very narrow crevices. A group of crabs is called a cast.
  4. Spider Crab The Japanese Spider Crab may live up to 100 years.
  5. The largest crab in the world is the giant Japanese Spider Crab, which can measure up to 13 feet across.
  6. Crabs are also known as “spiders of the sea” because, like crabs, spiders have legs that bend at joints.
  7. There are two kinds of crabs. First are true crabs, or brachyurans, which have a very short abdomen and use four pairs of long legs for walking. True crabs include blue crabs, spider crabs, and ghost crabs. Second are false crabs, or anomurans, which have a longer abdominal section and fewer walking legs. False crabs include hermit crabs, king crabs, horseshoe crabs,  crab lice and squat lobsters.
  8. There are about 5,000 species of crabs. Only about 4,500 are true crabs. The other 500 types are false crabs.
  9. All crabs have claws on their two front legs. All crabs have one pair of pincers (chelipeds) and four pairs of walking legs.
  10. A crab can use its claws as a vice for crushing or like scissors for cutting. They can also be used like chopsticks to pick up food.
  11. Crabs have large compound eyes made up of hundreds of tiny lenses. Eyes are set on eyestalks which can move in different directions and allow a crab to see all around. The stalk helps a crab see while hiding under water, rock, coral, sand, or mud.
  12. The Sally Lightfoot crab is the most colorful crab in the world. It is red, orange, yellow, and white but not considered very edible by humans.
  13. Crabs live in more different places than any other sea animal. They are found almost everywhere in the ocean, including smoking volcanic vents thousands of feet below the surface. They also live under the ice in Antarctica. One type of crab even lives on land and climbs trees.
  14. Crab lice, also known as “pubic lice,” are parasitic insects that live on humans. They can live any place where there is hair, including pubic hair and eyelashes. They feed only on blood.
  15. The word “cancer” is related to the word “crab” in Latin. Greek physicians Hippocrates and Galen, among others, noted the similarity of swollen tumors with veins to crabs.
  16. The coconut crab is a giant hermit crab that lives on islands in the Pacific Ocean and the Indian Ocean. It weighs up to 10 pounds, making it the world’s largest land invertebrate.
  17. Male and female crabs can be distinguished by looking at their abdomens. In most male crabs, the form of the abdomen (pleon) is narrow and triangular, while the females have a broader, rounder abdomen. Additionally, female crabs have smaller claws than male crabs.
  18. A female crab lays millions of eggs at one time. She carries them underneath her body until the eggs hatch. Crabs hatch as tiny larvae, just the size of the head of a pin. Crab larvae float for several weeks before settling to the ocean floor to hatch.
  19. Crabs communicate by flapping their pincers or drumming their claws.
  20. Humans eat about 1.5 million tons of crab every year. In fact crabs make up 1/5 of all creatures that are caught from bodies of water around the world.
  21. The Japanese Blue Crab or the Horse crab is the most consumed crab in the world.
  22. Crab meat is very high in vitamin B12. Just 2–3 ounces of crab meat will supply an adult with the daily B12 requirement.
  23. True crabs can walk slowly in any direction, but when they need to hurry, they usually move sideways.
  24. Pea crabs are the smallest of all crabs and, not surprisingly, are about the size of a pea.
  25. Some crabs, such as the spider crab, disguise themselves by attaching living things, such as anemones, to their bodies. These living decorations not only camouflage the crab, but the anemones’ stings also discourage predators.
  26. Crabs are omnivores. They are usually not picky eaters and will eat bits of dead plants and animals, algae, worms, detritus, or other crustaceans.
  27. Crabs have several predators, including seagulls, sea otters, octopuses, and humans.
  28. A crab may lose a claw or leg in a fight. In time, the claw or leg grows back.
  29. Crabs can live on land as long as they keep their gills moist.
  30. Crabs often work together to get food and to protect their families.
  31. A crab’s shell does not grow or stretch. When a grab gets bigger, it must climb out its shell in a process called molting. When a crab molts, a crack forms along the shell and then the crab backs out of it. Most crabs molt six or seven times during their first year of life, and then they molt just once or twice a year.
  32. Crabs are invertebrates, which mean they don’t have a backbone. In fact, more than 95% of all kinds of animals are invertebrates.
  33. Horseshoe crabs are not crabs at all. They are not even crustaceans. They belong to class named Merostomata. They have hardly changed since the age of the dinosaurs, and their closest living relatives are spiders.
  34. While crabs do not have teeth inside their mouth, some crabs such as the decorator and brown crabs have teeth in their stomachs. These grind against one another when the stomach contracts to mash up food.
  35. Amazing fact is that crabs can contract a terrifying parasite called a sacculina, which effectively castrates a crab and makes it incubate and hatch the parasite’s eggs. Additionally, due to loss of nutrition, the crab’s natural ability to grow another claw for defense purposes is also lost. 

By Amazing Facts 4U Team

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