Fully grown, it can reach a leg span of almost 4 metres (13 feet), a body size of up to 37 centimetres (15 inches) and a weight of up to 20 kilograms (44 pounds). [13], Female crabs carry the fertilized eggs attached to their abdominal appendages until they hatch into tiny planktonic larvae. The males have the longer chelipeds;[4] females have much shorter chelipeds, which are shorter than the following pair of legs. The Japanese spider crab will migrate to shallow waters (160 feet) during the breeding months of Spring (January to April). The biggest (legged): Japanese spider crab There is a debate as to whether this guy is the heaviest crab or not, but it definitely has the longest legs: these crabs can reach up to 12 feet (3.7 m) from claw to claw — that’s as long as a small car, to put things in perspective. The Japanese spider crab can survive even if it looses three of its walking legs. The males have the longer chelipeds; females have much shorter chelipeds, which are shorter than the following pair of legs. Enter a search request and press enter. It has a rounded body covered with stubby projections and long slim legs. It is thought that the optimum rearing temperature for all larval stages is between 15 °C-18 °C, with survival temperatures ranging from 11 °C-20 °C. [21] This proportionality explains, as in other Decapod Crustaceans, that spine size decreases as specimens grow older. [5], Once hatched, these larvae undergo four stages of development before they mature into adulthood. *NOTE* Polar Bears DO Live In Japan. Another differentiating feature is the supraorbital eave. It is the subject of fishery and is considered a delicacy. The genus Onicinopus has a semi-hardened body which allows the basal segment of the antennae, which articulates with the head capsule, to move. Today I want to write about the longest crabs in the world, the Japanese spider crabs. They are found most often in the Sagami, Suruga, and Tosa bays, as well as off the coast of the Kii peninsula. As a large decorator crab, the Japanese spider crab adorns its exoskeleton with algae and sponges to increase its camouflage to hide from predators like octopuses and fish. Giant Japanese spider crab is the largest arthropod’s representative. The smallest species has a shell that is around 8mm (0.3in) long, while the massive Japanese spider crab has a shell up to 50cm (20in) long. Aquarium Hours 10:00 a.m. - 5:30 p.m.; Festival Hours 5:30 p.m. - 9:30 p.m. Their Japanese name, Taka-Ashi-Gani, translates to “tall legs crab”. Miers. Adult males have very long front legs where the claws are located, but they are still shorter than the ambulatory legs of females, located in the back of the carapace and are used to move. Despite it's spindly, spider-like appearance, the Japanese spider crab is absurdly huge. Upon picking up the object with the crab's slender chelipeds, the chelae is used to twist and tear off the organism, such as a worm tube or sponge, from the substrate that it currently resides on.

[8] The Japanese name for this species is taka-ashi-gani, (japanese: たかあしがに), literally translating to “tall legs crab.” It also has a unique molting behavior that occurs for 103 minutes, in which the crab loses its mobility and starts molting its carapace rear and ends with molting its walking legs. [18] It was moved to the genus Inachus by Wilhem de Haan in 1839, but placed in a new subgenus, Macrocheira. [23] One of the primary methods of recovery of the species being utilized is restocking artificially cultured juvenile crabs in fisheries. Spider crabs come in a range of sizes. They can weigh up to 20 kilograms(44 pounds). What are ammonites, and how did they come ... And many can fly—either to escape predators or to find new sources of food, water, and shelter. Here is a Japanese spider crab on the bottom of the sea floor having a nice stroll. It is believed that living this arthropod canup to a hundred years. Japanese spider crab facts! The Japanese spider crab (タカアシガニ takaashigani, lit. A study has shown that nearly 3 quarters of these crabs are missing at least one limb. The Japanese spider crab is yet another deep-sea crustacean that makes the list. The Japanese spider crabs lack of sense of vision, but they compensate this lack, with their quite developed sense of hearing. [11] Unlike other species of crab, like the Chilean crab Acanthonyx petiveri, the Japanese spider crab does not specifically look for matching colors to blend into their environment; they simply camouflage in a way that disguises their entire structure. The Japanese spider crab has the greatest leg span of any arthropod, reaching up to 3.7 metres (12.1 ft) from claw to claw. [21] Like Oncinopus, the genus Macrocheira also has a seven segmented abdomen and a basal segment of antennae that is mobile, Macrocheira also has orbital parts, the eye socket and features around it, that are similar to differentiated genera. The long legs are considered weak, and giant spider crabs are often seen missing one leg. (20 kg). [1] Placed in the family Inachidae, M. kaempferi does not fit cleanly into that group, and it may be necessary to erect a new family just for the genus Macrocheira. [23] The population has decreased in number due to overfishing, forcing fishermen into exploring deeper waters to catch them. That subgenus was raised to the rank of genus in 1886 by Edward J. [23], "Systema Brachyurorum: Part I. Macrocheira Kaempferi undergoes two zoeal stages and a megalopa stage before it reaches adulthood. During the larval stages, Macrocheira kaempferi is found near the surface as the planktonic forms drift with ocean currents. [4] The Japanese spider crab is "occasionally collected for food,"[22] and even considered a delicacy in many parts of Japan and other areas in the region. The crab is known in Japan as “Taka-ashi-gani” which means “tall legs crab”. This crab is a decapod crustacean, which belongs to the group of spider crabs, so it is characterized for having a triangular shell and long legs. Females lay up to one million eggs. It’s got a resemblance with an awkward looking arachnid. Optimal temperatures see a 70% survival through the first zoeal stage which is greatly reduced to a 30% survival in the second zoeal and Megalopa stages. The spine of an adult giant crab is short and curves outward at the tip. [15] This surface water ranges between 12 °C and 15 °C during the hatching season (January to March). But Other Predators Are Possibly Dolphins, Squid, Octopuses And Sperm Whales. Japanese spider crab, Macrocheira kaempferi, at the Aquarium of the Pacific. Sign up to receive the latest news, upcoming events, and special offers! [12] They can lay up to 1.5 million eggs per season, and these eggs will hatch in 10 days on average. Only a few of the million offspring will survive to adulthood. As a large decorator crab, the Japanese spider crab adorns its exoskeleton with algae and sponges to increase its camouflage to hide from predators like octopuses and fish. [11], Japanese spider crabs are mostly found off the southern coasts of the Japanese island of Honshū, from Tokyo Bay to Kagoshima Prefecture. The Japanese name for this species is taka-ashi-gani literally translating to “tall legs crab.” Their armored exoskeletons help protect them from larger predators such as octopi, but giant spider crabs also use camouflage. Let’s meet this leggy denizen of the deep. This genus is similar in anatomical arrangement to the genus Oncinopus, seeming to preserve the earliest stage of anatomical evolution in the family Inachidae. If you continue using our website, we'll assume that you are happy to receive all cookies on this website and you agree to our Privacy Policy. They are omnivorous scavengers, feeding on any matter they can find on the seafloor and occasionally hunting for small invertebrates. [21] The antennulae which are segmented appendages between and below the eye stalks are connected to each other. Some have been known to scrape the ocean floor for plants and algae while others pry open the shells of mollusks. 18. [8] The Japanese name for this species is taka-ashi-gani, (Japanese: たかあしがに), literally translating to “tall legs crab.” It also has a unique molting behavior that occurs for 103 minutes, in which the crab loses its mobility and starts molting its carapace rear and ends with molting its walking legs. [15] Additionally, laws have been put into place in Japan which prohibit fishermen from harvesting spider crabs from January through April, which is during typical mating season when they are in shallower waters, and are more vulnerable to being caught. [11] This is most likely because Japanese spider crabs are nocturnally active, so instead of trying to disguise themselves when catching prey, they are actually just trying to avoid predators during the night. Not only does this mean that this crab could actually tower over you if it wanted to, but it also makes it the largest crab in the entire world. [17] The specific epithet commemorates Engelbert Kaempfer, a German naturalist who lived in Japan from 1690 to 1692 and wrote about the country's natural history. [1] As well as the single extant species, four species of the genus Macrocheira are known from fossils:[19][20], However, there is still evidence that the genus Macrocheira does come from this family in some way due to its anatomical arrangements. Pacific side of Japanese Islands, Konshu & Kyushu, Body 15 inches wide with leg span up to 15 feet, Carrion meat and decaying matter on the seabed. Since Japanese giant spider crabs have weak legs and move slowly, they need to hide from their predators, as they could never get away from them quickly enough. Mating behavior is rarely observed. Japanese spider crab performs on the ocean floor the same work as the bird vulture on land. Animals and Nature › Crustaceans › Crabs › Spider crabs › [23] This is a protection method that seeks to keep natural populations growing, and enables time for juvenile spider crabs to go through the early stages of their life cycle. Specifications: It’s the legs that make this crab big — its body stops growing at about 15 inches, but the legs keep growing and growing and can eventually extend 12 feet from claw to claw. This species goes through two zoeal stages (planktonic) and one megalopa stage, all of which happen rapidly. Then, through mechanical adhesion and secretions, the materials attach to the crab, and are able to regenerate, and colonize on the crab. Males have long chelipeds. An annotated checklist of extant Brachyuran crabs of the world", "Over het belang van Temminck's "Discours Préliminaire" voor de zoologische nomenclatuur", "Sizing ocean giants: patterns of intraspecific size variation in marine megafauna", "Japanese Spider Crabs Arrive at Aquarium", "Molting behavior of the giant spider crab, Macrocheira kaempferi in captivity", "Giant Japanese Spider Crab – Tennessee Aquarium", "Prezoeal Stage of Giant Spider Crab Macrocheira kaempferi (Crustacea, Decapoda, Majidae)", "Influence of temperature on survival and growth of larvae of the giant spider crab, "A classification of living and fossil genera of decapod crustaceans", https://en.wikipedia.org/w/index.php?title=Japanese_spider_crab&oldid=995567932, Creative Commons Attribution-ShareAlike License, This page was last edited on 21 December 2020, at 19:29.

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