Meet Nature's 7 Most Extraordinary Crab Species - Animalassic
Crabs, a diverse group of crustaceans, showcase a stunning array of adaptations that have captivated researchers and enthusiasts alike. From the deep sea to tropical shores, these creatures exhibit an astonishing range of sizes, colors, and behaviors. Some sport elaborate camouflage to blend seamlessly with their surroundings, while others wield something as unique as symbiotic venomous punching gloves for self-defense. Each species possesses unique traits that reflect its evolutionary journey and ecological niche, making them a fascinating subject of study and admiration.
Let's delve into the fascinating world of these extraordinary crab species, exploring their habitats, behaviors, and remarkable features that set them apart in the realm of nature's wonders.
H eikegani Crab
Heikegani were used by Carl Sagan in his popular science television series Cosmos: A Personal Voyage as an example of unintentional artificial selection, an interpretation originally published by Julian Huxley in 1952. According to this hypothesis, the crabs with shells resembling samurai were thrown back to the sea by fishermen out of respect for the Heike warriors, while those not resembling samurai were eaten, giving the former a greater chance of reproducing. Therefore, the more closely the crabs resembled a samurai face, the more probable they would be spared and thrown back to the sea.
This idea has met with some skepticism. Joel Martin, For instance, Joel Martin points out that humans don't eat Heikegani, so there's no pressure for shell patterns resembling faces, unlike what Sagan suggested. The ridges on the shell actually serve a functional purpose as attachment sites for muscles. Similar patterns are found on the shells of other crab species worldwide, including many fossil species.
J apanese Spider Crab
The Japanese spider crab (Macrocheira kaempferi) is a species of marine crab and is the largest one that inhabits the waters around Japan, weighing up to 19 kg. It has the largest known leg-span of any arthropod, measuring around 3.7 meters. The Japanese name for this species is taka-ashi-gani (Japanese: たかあしがに), which literally translates to 'tall legs crab.' It progresses through three primary larval stages along with a prezoeal stage to attain its great size. Due to its colossal proportions, it is sometimes referred to as a real-life kaiju. Though it is reported to have a gentle disposition despite its ferocious appearance and size.
The Japanese spider crab was first described by Western science in 1836 by Coenraad Jacob Temminck under the name 'Maja kaempferi'. Temminck, in his original description, noted that the crab was recognized by the locals for the serious injuries they can inflict with thier strong claws.
Two fossil species of this genus have been discovered, M. ginzanensis and M. yabei, both from the Miocene era of Japan.
These giant crabs are sought after by crab fisheries and are considered a delicacy in Japan. In order to prevent overexploitation from endangering the species, conservation efforts have been implemented to safeguard these creatures and their populations from overfishing.
B oxer Crab
Lybia tessellata, commonly known as the pom-pom crab or boxer crab, is a small crab species endemic to the Hawaiian Islands. Its distinctive feature lies in its peculiar habit of carrying stinging sea anemones in each of its claws, resembling pom-poms or boxing gloves. This behavior serves as both a defensive mechanism against predators and a potential means to stun prey. In ancient times, this intriguing creature was even utilized by individuals claiming to possess sorcerous abilities.
Unlike most crabs, it possesses relatively unarmored chelae, making it less adept at both defense and feeding. However, this vulnerability is offset by its ingenious use of sea anemones. The anemones it carries are small sea anemones, usually Bunodeopsis spp. or Triactis producta, in each chela, holding its chelipeds out horizontally while moving around. The sea anemones it holds are grasped delicately with its chelae and held in place by several small spines, while the chelipeds are held out horizontally while moving around.
Unlike most crabs, it possesses relatively unarmored chelae, making it less adept at both defense and feeding. However, this vulnerability is offset by its ingenious use of sea anemones. The anemones it carries are small sea anemones, usually Bunodeopsis spp. or Triactis producta, in each chela, holding its chelipeds out horizontally while moving around. The sea anemones it holds are grasped delicately with its chelae and held in place by several small spines, while the chelipeds are held out horizontally while moving around.
When attacked by a potential predator, it will threaten the aggressor with an anemone, the tentacles of which are well-armed with cnidocytes (stinging cells). It is unable to feed itself with its chelae and uses the tentacles of the anemones to collect food particles, which it then removes with its mobile maxillipeds.
They can be found in shallow water in the tropical Indo-Pacific region, with their range extending from the Red Sea and the East African coast to Indonesia and New Guinea. It is found on sandy and gravelly seabeds, where it is well-camouflaged, and on live corals where it clings with its long, thin legs.
P ancake Crab
The Red egg crab, or Atergatis integerrimus, is a species of reef crab from the family Xanthidae. Similarly, like all xanthid crabs, the red egg crabs are highly poisonous, so much so that the toxins they contain are not destroyed by cooking, and no antidote is known for them.
Toxins present in the crab's body are similar to tetrodotoxin and paralytic shellfish toxin (saxitoxin) produced by puffer fish, which are synthesized by the bacteria of the genus Vibrio, mostly V. alginolyticus and V. parahaemolyticus, which live in symbiosis with the crab.
Among some internet users, these crabs are popularly known as 'Pancake crabs.' They are referred to as such because of their appearance they exhibit during their juvenile and sub-adult stages of life. The juveniles of the species are light brown with a white band around the edge of the body, which gives them an appearance similar to that of Dorayakis, a Japanese confection also known as Dora cakes.
As the crab becomes more mature, the size of the crab increases, the white band of the ridges shrinks, and the shell becomes darker in color and more oval-shaped, losing their dorayaki-like appearance and becoming more similar in appearance to pancakes, with the development of light white spots on the carapace.
The adults of the species have a large oval, somewhat egg-shaped body with a smooth edge, and the hue of their shells ranges from reddish-brown to bright red, usually with scattered white spots. The pincers are large and equal in size, with smooth, spoon-shaped black tips. Males may have larger pincers and lack hair on their walking legs.
The adults of the species have a large oval, somewhat egg-shaped body with a smooth edge, and the hue of their shells ranges from reddish-brown to bright red, usually with scattered white spots. The pincers are large and equal in size, with smooth, spoon-shaped black tips. Males may have larger pincers and lack hair on their walking legs.
Y eti Crab
Kiwa hirsuta, also known as the 'yeti crab,' is a species belonging to the family Kiwaidae. They typically measure approximately 15 cm (5.9 in) in length and are notable for the abundance of silky blond setae (resembling fur) covering their pereiopods (thoracic legs, including claws). This abundance of setae gives them a hairy and fuzzy appearance, due to which they are commonly referred to as "yeti lobsters" or "yeti crabs”, after the mythical yeti.
Despite its name, K. hirsuta isn't a crab or a lobster but a squat lobster, which is more closely related to crabs and hermit crabs than true lobsters. It belongs to a separate biological family called Kiwaidae, which currently has only four described species (K.hirsuta, K. araonae, K. puravida & Kiwa araonae). K. hirsuta was discovered in March 2005.It was found along the Pacific-Antarctic Ridge, 1,500 kilometers (930 mi) south of Easter Island at a depth of 2,200 meters (7,200 ft), living on hydrothermal vents. These vents provide hot water which forms the habitat where these crabs thrive.
Despite its name, K. hirsuta isn't a crab or a lobster but a squat lobster, which is more closely related to crabs and hermit crabs than true lobsters. It belongs to a separate biological family called Kiwaidae, which currently has only four described species (K.hirsuta, K. araonae, K. puravida & Kiwa araonae). K. hirsuta was discovered in March 2005.It was found along the Pacific-Antarctic Ridge, 1,500 kilometers (930 mi) south of Easter Island at a depth of 2,200 meters (7,200 ft), living on hydrothermal vents. These vents provide hot water which forms the habitat where these crabs thrive.
The crabs regulate their ecosystem by using their bristly arms to collect toxins released from the hydrothermal vents. The "bristly" pincers contain filamentous bacteria, which the creature may utilize to detoxify harmful minerals from the water emitted by the hydrothermal vents where it resides. This process is known as chemosynthesis. Lipid and isotope analyses provide evidence that epibiotic bacteria are the crab's primary food source and K. puravida has highly modified setae (hairs) on its 3rd maxilliped (a mouth appendage) which it uses to harvest these bacteria. Yeti crabs receive most of their essential nutrients from chemosynthetic episymbiotic bacteria which grows on hairlike setae.
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Fun Fact: Crabominable, the Woolly Crab Pokémon, takes its inspiration from the Yeti crab
C oconut Crab
The coconut crab (Birgus latro) is a terrestrial species of giant hermit crab and is also known as the robber crab or palm thief. It is both the largest living terrestrial arthropod and the largest living terrestrial invertebrate known, with a weight of up to 4.1 kg (9 lb) and a body length of up to 40 cm (16 in).
Coconut crabs are considered one of the most terrestrial-adapted decapods. Except as larvae, coconut crabs cannot swim, and they drown if left in water for more than an hour.
They use a special organ called a branchiostegal lung to breathe. This organ can be interpreted as a developmental stage between gills and lungs and is one of the most significant adaptations of the coconut crab to its habitat.These crabs also possess a stronger grip than any other known animal. The force exerted by their powerful claws can be up to 740 psi, which is approximately 90 times their own body weight and four to five times as strong as the force the human jaw can produce.
Coconut crabs have developed quite a reputation for being kleptomaniacs. Whenever they come across something shiny or potential food, these crabs seize the opportunity without hesitation. People have reported incidents of stolen items such as cutlery, pots and pans, whiskey bottles, shoes, camp stoves, machetes, wristwatches, and more. It seems that nothing is safe from the thieving antics of these crabs. Coconut crabs are not innately poisonous themselves, but they may become so depending on their diet, and cases of coconut crab poisoning have occurred.
They use a special organ called a branchiostegal lung to breathe. This organ can be interpreted as a developmental stage between gills and lungs and is one of the most significant adaptations of the coconut crab to its habitat.These crabs also possess a stronger grip than any other known animal. The force exerted by their powerful claws can be up to 740 psi, which is approximately 90 times their own body weight and four to five times as strong as the force the human jaw can produce.
Coconut crabs have developed quite a reputation for being kleptomaniacs. Whenever they come across something shiny or potential food, these crabs seize the opportunity without hesitation. People have reported incidents of stolen items such as cutlery, pots and pans, whiskey bottles, shoes, camp stoves, machetes, wristwatches, and more. It seems that nothing is safe from the thieving antics of these crabs. Coconut crabs are not innately poisonous themselves, but they may become so depending on their diet, and cases of coconut crab poisoning have occurred.
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Fun Fact: Crabominable's pre-evolution, Crabrawler, is based on the Coconut crab.
C andy Crab
The Candy Crab (Hoplophrys oatesi), also known as Oates's soft coral crab, commensal soft coral crab, and Dendronephthya crab, is a colorful species of crab in the family Epialtidae. It belongs to the monotypic genus Hoplophrys and is the sole member of the genus.
They are quite small in size, with an average length of 1.5 to 2 cm. As for the diet, they feed on plankton.Candy crabs inhabit various species of soft coral in the genus Dendronephthya. The crab camouflages itself by mimicking the colors of the polyps among which it hides and further enhances its camouflage by attaching polyps to its carapace. Colors vary depending on the color of the coral and may be white, pink, yellow, or red.
The first pair of legs of this species has small claws. The body has pointed spines with a red and white pattern, similar in appearance to the host coral. Candy crabs are a widespread species in the Indo-Pacific in tropical climates and can be found in the benthic zone at depths of 1–90 meters (3 ft 3 in – 295 ft 3 in).
References
- Hoplophrys Genus hoplophrys. iNaturalist. (n.d.-b). Retrived on March 28, 2024, from
https://www.inaturalist.org/taxa/51727-Birgus-latro - Coconut crab (Birgus Latro). iNaturalist. (n.d.-a). Retrived on March 28, 2024 from
https://www.inaturalist.org/taxa/51727-Birgus-latro
- Samurai Crab (heikeopsis japonica). iNaturalist. (n.d.-c). Retrived on March 28, 2024, from https://www.inaturalist.org/taxa/492228-Heikeopsis-japonica.
- Yeti Crabs (family Kiwaidae). iNaturalist. (n.d.-e).
Retrived on March 28, 2024, from https://www.inaturalist.org/taxa/69646-Kiwaidae /.
- Red Egg Crab (Atergatis integerrimus). (n.d.).
Retrived on March 28, 2024, from http://www.wildsingapore.com/wildfacts/crustacea/crab/xanthidae/integerrimus.htm .
- Boxer crab (Lybia tessellata). iNaturalist Guatemala. (n.d.).
Retrived on March 28, 2024, from https://guatemala.inaturalist.org/taxa/51177-Lybia-tessellata .
- Japanese spider crab (Macrocheira Kaempferi). iNaturalist. (n.d.-c).
Retrived on March 28, 2024, from https://www.inaturalist.org/taxa/127535-Macrocheira-kaempferi..
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