This article will introduce you to several types of crabs with peculiar characteristics and behaviors. Featuring a broad spectrum, this post will offer a fascinating glimpse into our planet’s splendid biodiversity.
Behind every pincer and shell is an intriguing study of survival and adaptation. Let us take a deep dive into the many types of crab.
Fun Fact: Did you know the Blue Crab is not blue? Its name comes from the blue tint of its claws and carapace. However, these crabs can also turn greenish-brown or even red.
The blue crab lives in the Gulf of Mexico and the western Atlantic Ocean. Besides blue claws, female blue crabs also have a dash of red on their pincers. Moreover, they eat algae, snails, and fish, though they eat other blue crabs occasionally. Fishers catch these crabs during molting, hence their other name, “soft shell crab.”
Fun Fact: Did you know that the Dungeness crab gets its name from the coastal town of Dungeness in Washington State? This crab species has sweet and tender meat, a popular choice for seafood lovers.
These crabs have oval-shaped, purplish-brown shells and claws tipped in white. You can also find them up to 300 meters underwater, disappearing into the sandy or muddy seafloor to avoid predators.
As nocturnal animals, the Dungeness Crabs emerge to look for their next meal, including fish, clams, marine worms, and other crustaceans. Their broad diet gives their flesh a rich, buttery, and sweet taste.
Fun Fact: Did you know that the Red King Crab is not only one of the largest crab species but also one of the longest-living crabs in the world? These creatures can live up to 30 years in the wild.
The red king crab lives in the Bering Sea, the Gulf of Alaska, the icy shores of Japan, and the Kamchatka Peninsula. Moreover, this crab has robust claws and long, spiny legs. Male red king crabs weigh up to five feet long and weigh 24 pounds.
Additionally, they live at frigid depths of 90 to 200 meters with temperatures between 34-38 degrees Fahrenheit.
Fun Fact: Did you know that hermit crabs are not true crabs? While they may look like typical crabs with hard exoskeletons and pincers, hermit crabs belong to a different group called Paguroidea. Their shells are also empty seashells; they must find larger shells to accommodate their growing bodies. Moreover, they can swap shells with other hermit crabs for more spacious and comfortable dwellings4.
Hermit crabs are soft-bodied members of the Paguroidea superfamily. Unlike most crabs, they live in borrowed sea snail shells, turning them into mobile shields against ocean predators. Despite the 'hermit' label, these crabs are social creatures, forming large colonies in the wild.
These little guys also feature in our list of animals that start with h alongside the horseshoe crab (below)
Fun Fact: Did you know that snow crabs can regenerate lost limbs? If a snow crab loses a leg or claw in a fight or accident, it can grow a new one in months. This regenerative ability allows them to survive their icy habitats.
Snow crabs inhabit the frosty depths of the northern Pacific and Atlantic Oceans; most of them live in the Bering Sea and off Canada’s coast. Like spiders, they have long, slender legs. They also flourish at depths of 2000 meters underwater. Moreover, snow crabs are massive; some have legs stretching up to five feet.
Fun Fact: Did you know that the Ghost Crab can scuttle across the sand at 10 miles per hour?
The nocturnal ghost crab has a pale body that helps it blend into sandy beaches. You can find them along the eastern shores of the United States and down to Brazil. Moreover, they can dig burrows up to four feet deep to avoid the sun. Additionally, their eyes are at the end of tall stalks, and they can turn 360 degrees, allowing them to spot food and threats without moving their bodies.
Fun Fact: Did you know that male fiddler crabs have one claw larger than their entire body? This claw does not only fight off rivals but also attracts females during courtship displays. Moreover, the male fiddler crab waves its giant claw in a mesmerizing dance2, almost like playing a fiddle, hence the name.
Fiddler crabs live in marshes, mangrove trees, and lagoons. Moreover, they burrow deep into the mud or sand, protecting them from predators. However, these burrows aerate the soil and help recycle nutrients.
Fun Fact: Did you know Florida stone crabs’ regenerative ability benefits humans? People eat them for their delicious claws, so fishers take only one claw instead of catching the entire animal. This sustainable fishing practice allows the crab to regrow its claw, ensuring a continuous supply.
If you spot a stone crab in Florida, you’ll likely see it has only one claw. The crab prefers the sunny coastal waters of the Sunshine State, which has adopted a sustainable fishing practice to help them thrive.
Fun Fact: Did you know that despite its name, the horseshoe crab is not a crab at all? It is more closely related to spiders and scorpions than to true crabs. Moreover, it has a long, pointed tail, further setting it apart from real crabs. These creatures have also existed for over 450 million years, making them one of the oldest living species on Earth!
The horseshoe crab has a carapace shaped like a horseshoe, which protects it from predators. Moreover, its long tail–or telson–guides the crab in the water like a rudder and helps the crab right itself if it gets flipped over. Additionally, its blood is blue, a result of copper-based molecules. This coloration allows doctors to detect bacterial contamination in vaccines and medical tools.
Fun Fact: Did you know that the coconut crab is not only the largest land-living arthropod but also the only species of crab that can climb trees? These fascinating creatures climb palm trees for coconuts, which they crack open with their powerful claws.
The coconut crab lives in the scattered tropical islands across the Indian and Pacific Oceans. However, besides coconuts, these crabs also eat seeds, other fruits, and the pith of fallen trees. They also won’t turn down the occasional carrion.
Fun Fact: Did you know that the mud crab can change their shell color to match their surroundings, making them nearly invisible to predators and prey alike?
The mud crab is also nocturnal1. Its dark and mottled shell helps it camouflage itself at the bottom of estuaries and mangroves from Africa to Asia, Australia, and the Pacific Islands. Moreover, this crab can survive in various salinities, often entering freshwater.
Fun Fact: Did you know that the Tasmanian Giant Crab is the largest in the world? These crustaceans can grow to a whopping 3 feet (1 meter) and weigh over 30 pounds (14 kilograms)!
Male Tasmanian giant crabs have massive, mismatched claws—one significantly larger than the other. However, females have equally sized claws. Males brandish their claws to put down rivals and attract potential mates.
Fun Fact: Did you know that the Christmas Island Red Crab undertakes one of the most impressive migrations in the animal kingdom? Around November or December, millions of these vibrant red crabs travel from the lush rainforests of Christmas Island to the island's coastline. This "Christmas Island crab migration" sees millions of red crabs scuttle across roads, climb trees, and even cross rivers to reach their breeding grounds.
Unlike most crabs, the Christmas Island Red Crab saves its marine adventures for annual migration. Their migration depends on the lunar calendar and the arrival of the wet season. When the migration begins, the crabs will stop at nothing to reach their breeding grounds, which often disrupts the island’s routines.
Fun Fact: Did you know that a sand crab, mole crab, or peekytoe crab filters tiny food particles from the sand? As waves wash over the beach, sand crabs extend their antennae to catch plankton and other organic matter. Then, they retract their antennae and consume the captured food.
The tiny sand crab has also mastered the art of camouflage. When necessary, the Sand Crab can vanish within seconds and plunge into the waters beneath, earning them the name “peekytoe crab.”
Fun Fact: Did you know the Yeti Crab is one of the deep sea's most mysterious creatures? Scientists discovered this crab in 2005 near hydrothermal vents in the depths of the Pacific Ocean.
The Yeti crab is covered in long, silky, hair-like strands called setae, which are also covered in bacteria that the crab cultivates and eats. Living in extreme conditions, the Yeti Crab thrives in deep-sea hydrothermal vents with intolerably high temperatures, releasing mineral-rich superheated water. However, scientists have yet to unravel this crab’s secrets and understand its survival mechanisms.
Fun Fact: Did you know the Japanese Spider Crabs have the longest leg span of the world’s arthropods since their legs can grow to 12 feet long?
Besides its spider-like legs, the Japanese spider crab is a master of camouflage, adorning its spiky carapace with sponges and other marine life. This disguise helps the crab move around underwater while avoiding predators. Moreover, the spikes on its shell help keep predators from getting too close.
Fun Fact: Did you know that Alaskan King Crabs can grow up to 6 feet long and weigh as much as 25 pounds, like a small dog?
This crab sits on its throne in the North Pacific Ocean. Moreover, it has a blue shell, adding color to its frigid underwater abode. Besides their size, Alaskan king crab legs can stretch up to five feet long.
Fun Fact: Did you know that the Sally Lightfoot crab quickly moves across rocks and even vertical surfaces?
The Sally Lightfoot Crab is the 'caretaker of the Galapagos Islands,’ removing parasites from marine iguanas. Moreover, humans do not treat this species as an edible crab; fishers use them as bait.
Fun Fact: Did you know that the Chinese Mitten Crab, also known as the Chinese Mitten Crab, can climb trees? While most crabs are primarily aquatic, the Mitten Crab has developed strong claws and leg muscles to climb trees and walls! They often climb obstacles when moving from freshwater to the ocean.
However, the Mitten Crab's uncanny ability to burrow can cause soil erosion and damage infrastructure. They are also an invasive species that can quickly dominate any new environment. For instance, females can lay up to a million eggs. Unsurprisingly, they can outcompete native species for resources and displace them from their natural habitat3.
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Detto, T., Backwell, P. R., Hemmi, J. M., & Zeil, J. (2006). Visually mediated species and neighbour recognition in fiddler crabs (Uca mjoebergi and Uca capricornis). Proceedings of the Royal Society B: Biological Sciences, 273(1598), 1661–1666.
Rudnick, D. A., Hieb, K., Grimmer, K. F., & Resh, V. H. (2003). Patterns and processes of biological invasion: The Chinese mitten crab in San Francisco Bay. Basic and Applied Ecology, 4(3), 249-262.
Hazlett, B. A. (1981). The behavioral ecology of hermit crabs. Annual Review of Ecology and Systematics, 12(1), 1-22.