138-412: See Taxonomy Scorpions are predatory arachnids of the order Scorpiones . They have eight legs and are easily recognized by a pair of grasping pincers and a narrow, segmented tail, often carried in a characteristic forward curve over the back and always ending with a stinger . The evolutionary history of scorpions goes back 435 million years . They mainly live in deserts but have adapted to
276-510: A clade within the pulmonate Arachnida (those with book lungs). Arachnida is placed within the Chelicerata , a subphylum of Arthropoda that contains sea spiders and horseshoe crabs , alongside terrestrial animals without book lungs such as ticks and harvestmen . The extinct Eurypterida , sometimes called sea scorpions, though they were not all marine, are not scorpions; their grasping pincers were chelicerae , not homologous with
414-455: A mutation (the deletion of two nucleotides ) that inactives it. These changes are explained by the fact that its prey does not need to be subdued. Several groups of predatory fish have the ability to detect, track, and sometimes, as in the electric ray , to incapacitate their prey by sensing and generating electric fields . The electric organ is derived from modified nerve or muscle tissue. Physiological adaptations to predation include
552-418: A better choice. If it chooses pursuit, its physical capabilities determine the mode of pursuit (e.g., ambush or chase). Having captured the prey, it may also need to expend energy handling it (e.g., killing it, removing any shell or spines, and ingesting it). Predators have a choice of search modes ranging from sit-and-wait to active or widely foraging . The sit-and-wait method is most suitable if
690-851: A broad range of taxa including arthropods. They are common among insects, including mantids, dragonflies , lacewings and scorpionflies . In some species such as the alderfly , only the larvae are predatory (the adults do not eat). Spiders are predatory, as well as other terrestrial invertebrates such as scorpions ; centipedes ; some mites , snails and slugs ; nematodes ; and planarian worms . In marine environments, most cnidarians (e.g., jellyfish , hydroids ), ctenophora (comb jellies), echinoderms (e.g., sea stars , sea urchins , sand dollars , and sea cucumbers ) and flatworms are predatory. Among crustaceans , lobsters , crabs , shrimps and barnacles are predators, and in turn crustaceans are preyed on by nearly all cephalopods (including octopuses , squid and cuttlefish ). Seed predation
828-467: A defensive posture. Some species stridulate to warn off predators by rubbing certain hairs, the stinger or the claws. Certain species have a preference for using either the claws or stinger as defense, depending on the size of the appendages. A few scorpions, such as Parabuthus , Centruroides margaritatus , and Hadrurus arizonensis , squirt venom in a narrow jet as far as 1 meter (3.3 ft) to warn off potential predators, possibly injuring them in
966-465: A defensive posture. Some species stridulate to warn off predators by rubbing certain hairs, the stinger or the claws. Certain species have a preference for using either the claws or stinger as defense, depending on the size of the appendages. A few scorpions, such as Parabuthus , Centruroides margaritatus , and Hadrurus arizonensis , squirt venom in a narrow jet as far as 1 meter (3.3 ft) to warn off potential predators, possibly injuring them in
1104-582: A food trap, mechanical stimulation, and electrical impulses to eventually catch and consume its prey. Some carnivorous fungi catch nematodes using either active traps in the form of constricting rings, or passive traps with adhesive structures. Many species of protozoa ( eukaryotes ) and bacteria ( prokaryotes ) prey on other microorganisms; the feeding mode is evidently ancient, and evolved many times in both groups. Among freshwater and marine zooplankton , whether single-celled or multi-cellular, predatory grazing on phytoplankton and smaller zooplankton
1242-477: A huge gulp of water and filtering it through their feathery baleen plates. Pursuit predators may be social , like the lion and wolf that hunt in groups, or solitary. Once the predator has captured the prey, it has to handle it: very carefully if the prey is dangerous to eat, such as if it possesses sharp or poisonous spines, as in many prey fish. Some catfish such as the Ictaluridae have spines on
1380-725: A kill, and the coyote can be either solitary or social. Other solitary predators include the northern pike, wolf spiders and all the thousands of species of solitary wasps among arthropods, and many microorganisms and zooplankton . Under the pressure of natural selection , predators have evolved a variety of physical adaptations for detecting, catching, killing, and digesting prey. These include speed, agility, stealth, sharp senses, claws, teeth, filters, and suitable digestive systems. For detecting prey , predators have well-developed vision , smell , or hearing . Predators as diverse as owls and jumping spiders have forward-facing eyes, providing accurate binocular vision over
1518-417: A ladder-like configuration; they contain cysts which produce spermatozoa . Both tubes end in a spermiduct , one on each side of the mesosoma. They connect to glandular symmetrical structures called paraxial organs, which end at the genital orifice. These secrete chitin -based structures which come together to form the spermatophore . The "tail" or metasoma consists of five segments and the telson , which
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#17327727197291656-415: A ladder-like configuration; they contain cysts which produce spermatozoa . Both tubes end in a spermiduct , one on each side of the mesosoma. They connect to glandular symmetrical structures called paraxial organs, which end at the genital orifice. These secrete chitin -based structures which come together to form the spermatophore . The "tail" or metasoma consists of five segments and the telson , which
1794-539: A long distance, sometimes for hours at a time. The method is used by human hunter-gatherers and by canids such as African wild dogs and domestic hounds. The African wild dog is an extreme persistence predator, tiring out individual prey by following them for many miles at relatively low speed. A specialised form of pursuit predation is the lunge feeding of baleen whales . These very large marine predators feed on plankton , especially krill , diving and actively swimming into concentrations of plankton, and then taking
1932-445: A patch and decide whether to spend time searching for prey in it. This may involve some knowledge of the preferences of the prey; for example, ladybirds can choose a patch of vegetation suitable for their aphid prey. To capture prey, predators have a spectrum of pursuit modes that range from overt chase ( pursuit predation ) to a sudden strike on nearby prey ( ambush predation ). Another strategy in between ambush and pursuit
2070-425: A powerful selective effect on prey, and the prey develop antipredator adaptations such as warning coloration , alarm calls and other signals , camouflage , mimicry of well-defended species, and defensive spines and chemicals. Sometimes predator and prey find themselves in an evolutionary arms race , a cycle of adaptations and counter-adaptations. Predation has been a major driver of evolution since at least
2208-785: A predator, while small prey might prove hard to find and in any case provide less of a reward. This has led to a correlation between the size of predators and their prey. Size may also act as a refuge for large prey. For example, adult elephants are relatively safe from predation by lions, but juveniles are vulnerable. Members of the cat family such as the snow leopard (treeless highlands), tiger (grassy plains, reed swamps), ocelot (forest), fishing cat (waterside thickets), and lion (open plains) are camouflaged with coloration and disruptive patterns suiting their habitats. In aggressive mimicry , certain predators, including insects and fishes, make use of coloration and behaviour to attract prey. Female Photuris fireflies , for example, copy
2346-421: A preferred target is scarce. When prey have a clumped (uneven) distribution, the optimal strategy for the predator is predicted to be more specialized as the prey are more conspicuous and can be found more quickly; this appears to be correct for predators of immobile prey, but is doubtful with mobile prey. In size-selective predation, predators select prey of a certain size. Large prey may prove troublesome for
2484-820: A relatively narrow field of view, whereas prey animals often have less acute all-round vision. Animals such as foxes can smell their prey even when it is concealed under 2 feet (60 cm) of snow or earth. Many predators have acute hearing, and some such as echolocating bats hunt exclusively by active or passive use of sound. Predators including big cats , birds of prey , and ants share powerful jaws, sharp teeth, or claws which they use to seize and kill their prey. Some predators such as snakes and fish-eating birds like herons and cormorants swallow their prey whole; some snakes can unhinge their jaws to allow them to swallow large prey, while fish-eating birds have long spear-like beaks that they use to stab and grip fast-moving and slippery prey. Fish and other predators have developed
2622-529: A sclerotized plate called the tergite . Ventrally , somites 3 to 7 are armored with matching plates called sternites . The ventral side of somite 1 has a pair of genital opercula covering the gonopore . Sternite 2 forms the basal plate bearing the pectines , which function as sensory organs. The next four somites, 3 to 6, all bear pairs of spiracles . They serve as openings for the scorpion's respiratory organs, known as book lungs . The spiracle openings may be slits, circular, elliptical or oval according to
2760-527: A sclerotized plate called the tergite . Ventrally , somites 3 to 7 are armored with matching plates called sternites . The ventral side of somite 1 has a pair of genital opercula covering the gonopore . Sternite 2 forms the basal plate bearing the pectines , which function as sensory organs. The next four somites, 3 to 6, all bear pairs of spiracles . They serve as openings for the scorpion's respiratory organs, known as book lungs . The spiracle openings may be slits, circular, elliptical or oval according to
2898-492: A scorpion can tolerate high osmotic pressure in its blood. Desert scorpions get most of their moisture from the food they eat but some can absorb water from the humid soil. Species that live in denser vegetation and in more moderate temperatures will drink water on plants and in puddles. A scorpion uses its stinger both for killing prey and defense. Some species make direct, quick strikes with their tails while others make slower, more circular strikes which can more easily return
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#17327727197293036-490: A scorpion can tolerate high osmotic pressure in its blood. Desert scorpions get most of their moisture from the food they eat but some can absorb water from the humid soil. Species that live in denser vegetation and in more moderate temperatures will drink water on plants and in puddles. A scorpion uses its stinger both for killing prey and defense. Some species make direct, quick strikes with their tails while others make slower, more circular strikes which can more easily return
3174-413: A scorpion is in the back of the cephalothorax, just above the esophagus . As in other arachnids, the nervous system is highly concentrated in the cephalothorax, but has a long ventral nerve cord with segmented ganglia which may be a primitive trait. The pedipalp is a segmented, clawed appendage used for prey immobilization, defense and sensory purposes. The segments of the pedipalp (from closest to
3312-411: A scorpion is in the back of the cephalothorax, just above the esophagus . As in other arachnids, the nervous system is highly concentrated in the cephalothorax, but has a long ventral nerve cord with segmented ganglia which may be a primitive trait. The pedipalp is a segmented, clawed appendage used for prey immobilization, defense and sensory purposes. The segments of the pedipalp (from closest to
3450-429: A shelter underneath stones a few centimeters long. Some may use burrows made by other animals including spiders, reptiles and small mammals. Other species dig their own burrows which vary in complexity and depth. Hadrurus species dig burrows as over 2 m (6 ft 7 in) deep. Digging is done using the mouth parts, claws and legs. In several species, particularly of the family Buthidae, individuals may gather in
3588-429: A shelter underneath stones a few centimeters long. Some may use burrows made by other animals including spiders, reptiles and small mammals. Other species dig their own burrows which vary in complexity and depth. Hadrurus species dig burrows as over 2 m (6 ft 7 in) deep. Digging is done using the mouth parts, claws and legs. In several species, particularly of the family Buthidae, individuals may gather in
3726-478: A significant amount of energy, to locate each food patch. For example, the black-browed albatross regularly makes foraging flights to a range of around 700 kilometres (430 miles), up to a maximum foraging range of 3,000 kilometres (1,860 miles) for breeding birds gathering food for their young. With static prey, some predators can learn suitable patch locations and return to them at intervals to feed. The optimal foraging strategy for search has been modelled using
3864-406: A small animal, gulping the prey in an extremely rapid movement when it is within range. Many smaller predators such as the box jellyfish use venom to subdue their prey, and venom can also aid in digestion (as is the case for rattlesnakes and some spiders ). The marbled sea snake that has adapted to egg predation has atrophied venom glands, and the gene for its three finger toxin contains
4002-523: A smaller area. For example, when mixed flocks of birds forage, the birds in front flush out insects that are caught by the birds behind. Spinner dolphins form a circle around a school of fish and move inwards, concentrating the fish by a factor of 200. By hunting socially chimpanzees can catch colobus monkeys that would readily escape an individual hunter, while cooperating Harris hawks can trap rabbits. Predators of different species sometimes cooperate to catch prey. In coral reefs , when fish such as
4140-412: A sting. About 25 species (fewer than one percent ) have venom capable of killing a human, which happens frequently in the parts of the world where they live, primarily where access to medical treatment is unlikely. Scorpions appear in art, folklore, mythology, and commercial brands. Scorpion motifs are woven into kilim carpets for protection from their sting. Scorpius is the name of a constellation;
4278-440: A variety of defences including the ability to hear the echolocation calls. Many pursuit predators that run on land, such as wolves, have evolved long limbs in response to the increased speed of their prey. Their adaptations have been characterized as an evolutionary arms race , an example of the coevolution of two species. In a gene centered view of evolution , the genes of predator and prey can be thought of as competing for
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4416-491: A variety of prey though some may be highly specialized; Isometroides vescus specializes on burrowing spiders. Prey size depends on the size of the species. Several scorpion species are sit-and-wait predators , which involves them waiting for prey at or near the entrance to their burrow. Others actively seek them out. Scorpions detect their prey with mechanoreceptive and chemoreceptive hairs on their bodies and capture them with their claws. Small animals are merely killed with
4554-491: A variety of prey though some may be highly specialized; Isometroides vescus specializes on burrowing spiders. Prey size depends on the size of the species. Several scorpion species are sit-and-wait predators , which involves them waiting for prey at or near the entrance to their burrow. Others actively seek them out. Scorpions detect their prey with mechanoreceptive and chemoreceptive hairs on their bodies and capture them with their claws. Small animals are merely killed with
4692-616: A very low metabolic rate , and a relatively inactive lifestyle. This enables some to survive six to twelve months of starvation. Most scorpions reproduce sexually, with male and female individuals; species in some genera, such as Hottentotta and Tityus , and the species Centruroides gracilis , Liocheles australasiae , and Ananteris coineaui have been reported, not necessarily reliably, to reproduce through parthenogenesis , in which unfertilized eggs develop into living embryos . Receptive females produce pheromones which are picked up by wandering males using their pectines to comb
4830-614: A very low metabolic rate , and a relatively inactive lifestyle. This enables some to survive six to twelve months of starvation. Most scorpions reproduce sexually, with male and female individuals; species in some genera, such as Hottentotta and Tityus , and the species Centruroides gracilis , Liocheles australasiae , and Ananteris coineaui have been reported, not necessarily reliably, to reproduce through parthenogenesis , in which unfertilized eggs develop into living embryos . Receptive females produce pheromones which are picked up by wandering males using their pectines to comb
4968-482: A wide range of environmental conditions, and can be found on all continents except Antarctica . There are over 2,500 described species , with 22 extant (living) families recognized to date. Their taxonomy is being revised to account for 21st-century genomic studies. Scorpions primarily prey on insects and other invertebrates , but some species hunt vertebrates . They use their pincers to restrain and kill prey, or to prevent their own predation. The venomous sting
5106-477: Is ballistic interception , where a predator observes and predicts a prey's motion and then launches its attack accordingly. Ambush or sit-and-wait predators are carnivorous animals that capture prey by stealth or surprise. In animals, ambush predation is characterized by the predator's scanning the environment from a concealed position until a prey is spotted, and then rapidly executing a fixed surprise attack. Vertebrate ambush predators include frogs, fish such as
5244-399: Is based on Soleglad and Fet (2003), which replaced Stockwell's older, unpublished classification. Further taxonomic changes are from papers by Soleglad et al. (2005). The extant taxa to the rank of family (numbers of species in parentheses ) are: Scorpions are found on all continents except Antarctica . The diversity of scorpions is greatest in subtropical areas; it decreases toward
5382-447: Is based on Soleglad and Fet (2003), which replaced Stockwell's older, unpublished classification. Further taxonomic changes are from papers by Soleglad et al. (2005). The extant taxa to the rank of family (numbers of species in parentheses) are: Scorpions are found on all continents except Antarctica . The diversity of scorpions is greatest in subtropical areas; it decreases toward the poles and equator, though scorpions are found in
5520-473: Is being revised to account for 21st-century genomic studies. Scorpions primarily prey on insects and other invertebrates , but some species hunt vertebrates . They use their pincers to restrain and kill prey, or to prevent their own predation. The venomous sting is used for offense and defense. During courtship, the male and female grasp each other's pincers and dance while he tries to move her onto his sperm packet . All known species give live birth and
5658-494: Is common, and found in many species of nanoflagellates , dinoflagellates , ciliates , rotifers , a diverse range of meroplankton animal larvae, and two groups of crustaceans, namely copepods and cladocerans . To feed, a predator must search for, pursue and kill its prey. These actions form a foraging cycle. The predator must decide where to look for prey based on its geographical distribution; and once it has located prey, it must assess whether to pursue it or to wait for
Scorpion - Misplaced Pages Continue
5796-866: Is into the clades Buthida and Iurida. The Bothriuridae diverged starting before temperate Gondwana broke up into separate land masses, completed by the Jurassic . The Iuroidea and Chactoidea are both seen not to be single clades, and are shown as " paraphyletic " (with quotation marks) in this 2018 cladogram. Chaeriloidea [REDACTED] Pseudochactoidea [REDACTED] Buthoidea [REDACTED] " Iuroidea " (part) Bothriuroidea [REDACTED] " Chactoidea " (part) " Iuroidea " (part) " Chactoidea " (part) Scorpionoidea [REDACTED] Carl Linnaeus described six species of scorpion in his genus Scorpio in 1758 and 1767; three of these are now considered valid and are called Scorpio maurus , Androctonus australis , and Euscorpius carpathicus ;
5934-810: Is into the clades Buthida and Iurida. The Bothriuridae diverged starting before temperate Gondwana broke up into separate land masses, completed by the Jurassic . The Iuroidea and Chactoidea are both seen not to be single clades, and are shown as " paraphyletic " (with quotation marks) in this 2018 cladogram. Chaeriloidea [REDACTED] Pseudochactoidea [REDACTED] Buthoidea [REDACTED] " Iuroidea " (part) Bothriuroidea [REDACTED] " Chactoidea " (part) " Iuroidea " (part) " Chactoidea " (part) Scorpionoidea [REDACTED] Carl Linnaeus described six species of scorpion in his genus Scorpio in 1758 and 1767; three of these are now considered valid and are called Scorpio maurus , Androctonus australis , and Euscorpius carpathicus ;
6072-421: Is not strictly a segment. The five segments are merely body rings; they lack apparent sterna or terga, and become larger distally. These segments have keels, setae and bristles which may be used for taxonomic classification. The anus is at the distal and ventral end of the last segment, and is encircled by four anal papillae and the anal arch. The tails of some species contain light receptors. The telson includes
6210-419: Is not strictly a segment. The five segments are merely body rings; they lack apparent sterna or terga, and become larger distally. These segments have keels, setae and bristles which may be used for taxonomic classification. The anus is at the distal and ventral end of the last segment, and is encircled by four anal papillae and the anal arch. The tails of some species contain light receptors. The telson includes
6348-518: Is restricted to mammals, birds, and insects but is found in almost all terrestrial ecosystems. Egg predation includes both specialist egg predators such as some colubrid snakes and generalists such as foxes and badgers that opportunistically take eggs when they find them. Some plants, like the pitcher plant , the Venus fly trap and the sundew , are carnivorous and consume insects . Methods of predation by plants varies greatly but often involves
6486-430: Is size. Prey that is too small may not be worth the trouble for the amount of energy it provides. Too large, and it may be too difficult to capture. For example, a mantid captures prey with its forelegs and they are optimized for grabbing prey of a certain size. Mantids are reluctant to attack prey that is far from that size. There is a positive correlation between the size of a predator and its prey. A predator may assess
6624-485: Is subdivided into a broad anterior portion, the mesosoma or pre-abdomen, and a narrow tail-like posterior, the metasoma or post-abdomen. External differences between the sexes are not obvious in most species. In some, the metasoma is more elongated in males than females. The cephalothorax comprises the carapace , eyes, chelicerae (mouth parts), pedipalps (which have chelae , commonly called claws or pincers) and four pairs of walking legs . Scorpions have two eyes on
6762-483: Is subdivided into a broad anterior portion, the mesosoma or pre-abdomen, and a narrow tail-like posterior, the metasoma or post-abdomen. External differences between the sexes are not obvious in most species. In some, the metasoma is more elongated in males than females. The cephalothorax comprises the carapace , eyes, chelicerae (mouth parts), pedipalps (which have chelae , commonly called claws or pincers) and four pairs of walking legs . Scorpions have two eyes on
6900-614: Is the romanization of the Greek σκορπίος – skorpíos , with no native IE etymology (cfr. Arabic ʕaqrab 'scorpion', Proto-Germanic *krabbô 'crab'). Scorpion fossils have been found in many strata , including marine Silurian and estuarine Devonian deposits, coal deposits from the Carboniferous Period and in amber . Whether the early scorpions were marine or terrestrial has been debated, and while they had book lungs like modern terrestrial species,
7038-423: Is then sucked into the gut in liquid form. Any solid indigestible matter (such as exoskeleton fragments) is trapped by setae in the pre-oral cavity and ejected. The sucked-in food is pumped into the midgut by the pharynx , where it is further digested. The waste passes through the hindgut and out of the anus. Scorpions can consume large amounts of food during one meal. They have an efficient food storage organ and
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#17327727197297176-423: Is then sucked into the gut in liquid form. Any solid indigestible matter (such as exoskeleton fragments) is trapped by setae in the pre-oral cavity and ejected. The sucked-in food is pumped into the midgut by the pharynx , where it is further digested. The waste passes through the hindgut and out of the anus. Scorpions can consume large amounts of food during one meal. They have an efficient food storage organ and
7314-507: Is used for offense and defense. During courtship, the male and female grasp each other's pincers and dance while he tries to move her onto his sperm packet . All known species give live birth and the female cares for the young as their exoskeletons harden, transporting them on her back. The exoskeleton contains fluorescent chemicals and glows under ultraviolet light. The vast majority of species do not seriously threaten humans, and healthy adults usually do not need medical treatment after
7452-456: The Cambrian period. At the most basic level, predators kill and eat other organisms. However, the concept of predation is broad, defined differently in different contexts, and includes a wide variety of feeding methods; moreover, some relationships that result in the prey's death are not necessarily called predation. A parasitoid , such as an ichneumon wasp , lays its eggs in or on its host;
7590-513: The Carboniferous Period and in amber . Whether the early scorpions were marine or terrestrial has been debated, and while they had book lungs like modern terrestrial species, the most basal such as Eramoscorpius were likely still aquatic. Over 100 fossil species of scorpion have been described. The oldest found as of 2021 is Dolichophonus loudonensis , which lived during the Silurian, in present-day Scotland. Gondwanascorpio from
7728-506: The IUCN Red List ; Lychas braueri is classed as critically endangered (2014), Isometrus deharvengi as endangered (2016) and Chiromachus ochropus as vulnerable (2014). Scorpions are xerocoles , meaning they primarily live in deserts , but they can be found in virtually every terrestrial habitat including high-elevation mountains, caves, and intertidal zones . They are largely absent from boreal ecosystems such as
7866-465: The angel shark , the northern pike and the eastern frogfish . Among the many invertebrate ambush predators are trapdoor spiders and Australian Crab spiders on land and mantis shrimps in the sea. Ambush predators often construct a burrow in which to hide, improving concealment at the cost of reducing their field of vision. Some ambush predators also use lures to attract prey within striking range. The capturing movement has to be rapid to trap
8004-455: The common garter snake has developed a resistance to the toxin in the skin of the rough-skinned newt . Predators affect their ecosystems not only directly by eating their own prey, but by indirect means such as reducing predation by other species, or altering the foraging behaviour of a herbivore, as with the biodiversity effect of wolves on riverside vegetation or sea otters on kelp forests. This may explain population dynamics effects such as
8142-414: The grasshopper mouse and desert long-eared bat , which are also immune to their venom. In one study, 70% of the latter's droppings contained scorpion fragments. Scorpions host parasites including mites , scuttle flies , nematodes and some bacteria. The immune system of scorpions gives them resistance to infection by many types of bacteria. When threatened, a scorpion raises its claws and tail in
8280-410: The grasshopper mouse and desert long-eared bat , which are also immune to their venom. In one study, 70% of the latter's droppings contained scorpion fragments. Scorpions host parasites including mites , scuttle flies , nematodes and some bacteria. The immune system of scorpions gives them resistance to infection by many types of bacteria. When threatened, a scorpion raises its claws and tail in
8418-475: The grouper and coral trout spot prey that is inaccessible to them, they signal to giant moray eels , Napoleon wrasses or octopuses . These predators are able to access small crevices and flush out the prey. Killer whales have been known to help whalers hunt baleen whales . Social hunting allows predators to tackle a wider range of prey, but at the risk of competition for the captured food. Solitary predators have more chance of eating what they catch, at
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#17327727197298556-470: The host ) and parasitoidism (which always does, eventually). It is distinct from scavenging on dead prey, though many predators also scavenge ; it overlaps with herbivory , as seed predators and destructive frugivores are predators. Predators may actively search for or pursue prey or wait for it, often concealed. When prey is detected, the predator assesses whether to attack it. This may involve ambush or pursuit predation , sometimes after stalking
8694-463: The littoral zone of rivers in Romania, occupy specialized niches. Scorpions range in size from the 8.5 mm (0.33 in) Typhlochactas mitchelli of Typhlochactidae, to the 23 cm (9.1 in) Heterometrus swammerdami of Scorpionidae. The body of a scorpion is divided into two parts or tagmata : the cephalothorax or prosoma , and the abdomen or opisthosoma . The opisthosoma
8832-403: The littoral zone of rivers in Romania, occupy specialized niches. Scorpions range in size from the 8.5 mm (0.33 in) Typhlochactas mitchelli of Typhlochactidae, to the 23 cm (9.1 in) Heterometrus swammerdami of Scorpionidae. The body of a scorpion is divided into two parts or tagmata : the cephalothorax or prosoma , and the abdomen or opisthosoma . The opisthosoma
8970-465: The marginal value theorem . Search patterns often appear random. One such is the Lévy walk , that tends to involve clusters of short steps with occasional long steps. It is a good fit to the behaviour of a wide variety of organisms including bacteria, honeybees, sharks and human hunter-gatherers. Having found prey, a predator must decide whether to pursue it or keep searching. The decision depends on
9108-560: The order Scorpiones . They have eight legs and are easily recognized by a pair of grasping pincers and a narrow, segmented tail, often carried in a characteristic forward curve over the back and always ending with a stinger . The evolutionary history of scorpions goes back 435 million years . They mainly live in deserts but have adapted to a wide range of environmental conditions, and can be found on all continents except Antarctica . There are over 2,500 described species , with 22 extant (living) families recognized to date. Their taxonomy
9246-535: The tundra , high-altitude taiga , and mountain tops. The highest altitude reached by a scorpion is 5,500 meters (18,000 ft) in the Andes, for Orobothriurus crassimanus . As regards microhabitats , scorpions may be ground-dwelling, tree-loving , rock-loving or sand-loving . Some species, such as Vaejovis janssi , are versatile and are found in all habitats on Socorro Island , Baja California , while others such as Euscorpius carpathicus , endemic to
9384-480: The tundra , high-altitude taiga , and mountain tops. The highest altitude reached by a scorpion is 5,500 meters (18,000 ft) in the Andes, for Orobothriurus crassimanus . As regards microhabitats , scorpions may be ground-dwelling, tree-loving , rock-loving or sand-loving . Some species, such as Vaejovis janssi , are versatile and are found in all habitats on Socorro Island , Baja California , while others such as Euscorpius carpathicus , endemic to
9522-447: The vesicle , which contains a symmetrical pair of venom glands . Externally it bears the curved stinger, the hypodermic aculeus, equipped with sensory hairs. Each of the venom glands has its own duct to convey its secretion along the aculeus from the bulb of the gland to immediately near of the tip, where each of the paired ducts has its own venom pore. An extrinsic muscle system in the tail moves it forward and propels and penetrates with
9660-446: The vesicle , which contains a symmetrical pair of venom glands . Externally it bears the curved stinger, the hypodermic aculeus, equipped with sensory hairs. Each of the venom glands has its own duct to convey its secretion along the aculeus from the bulb of the gland to immediately near of the tip, where each of the paired ducts has its own venom pore. An extrinsic muscle system in the tail moves it forward and propels and penetrates with
9798-525: The Devonian is among the earliest-known terrestrial animals on the Gondwana supercontinent. Some Palaeozoic scorpions possessed compound eyes similar to those of eurypterids. The Triassic fossils Protochactas and Protobuthus belong to the modern clades Chactoidea and Buthoidea respectively, indicating that the crown group of modern scorpions had emerged by this time. The Scorpiones are
9936-709: The ability of predatory bacteria to digest the complex peptidoglycan polymer from the cell walls of the bacteria that they prey upon. Carnivorous vertebrates of all five major classes (fishes, amphibians, reptiles, birds, and mammals) have lower relative rates of sugar to amino acid transport than either herbivores or omnivores, presumably because they acquire plenty of amino acids from the animal proteins in their diet. To counter predation, prey have evolved defences for use at each stage of an attack. They can try to avoid detection, such as by using camouflage and mimicry . They can detect predators and warn others of their presence. If detected, they can try to avoid being
10074-733: The ability to crush or open the armoured shells of molluscs. Many predators are powerfully built and can catch and kill animals larger than themselves; this applies as much to small predators such as ants and shrews as to big and visibly muscular carnivores like the cougar and lion . Predators are often highly specialized in their diet and hunting behaviour; for example, the Eurasian lynx only hunts small ungulates . Others such as leopards are more opportunistic generalists, preying on at least 100 species. The specialists may be highly adapted to capturing their preferred prey, whereas generalists may be better able to switch to other prey when
10212-417: The aculeus, while an intrinsic muscle system attached to the glands pumps venom through the stinger into the intended victim. The stinger contains metalloproteins with zinc, hardening the tip. The optimal stinging angle is around 30 degrees relative to the tip. Most scorpion species are nocturnal or crepuscular , finding shelter during the day in burrows, cracks in rocks and tree bark. Many species dig
10350-413: The aculeus, while an intrinsic muscle system attached to the glands pumps venom through the stinger into the intended victim. The stinger contains metalloproteins with zinc, hardening the tip. The optimal stinging angle is around 30 degrees relative to the tip. Most scorpion species are nocturnal or crepuscular , finding shelter during the day in burrows, cracks in rocks and tree bark. Many species dig
10488-584: The assault. When animals eat seeds ( seed predation or granivory ) or eggs ( egg predation ), they are consuming entire living organisms, which by definition makes them predators. Scavengers , organisms that only eat organisms found already dead, are not predators, but many predators such as the jackal and the hyena scavenge when the opportunity arises. Among invertebrates, social wasps such as yellowjackets are both hunters and scavengers of other insects. While examples of predators among mammals and birds are well known, predators can be found in
10626-684: The back (dorsal) and belly (pectoral) which lock in the erect position; as the catfish thrashes about when captured, these could pierce the predator's mouth, possibly fatally. Some fish-eating birds like the osprey avoid the danger of spines by tearing up their prey before eating it. In social predation, a group of predators cooperates to kill prey. This makes it possible to kill creatures larger than those they could overpower singly; for example, hyenas , and wolves collaborate to catch and kill herbivores as large as buffalo, and lions even hunt elephants. It can also make prey more readily available through strategies like flushing of prey and herding it into
10764-596: The body outward) are coxa, trochanter, femur, patella, tibia (including the fixed claw and the manus) and tarsus (moveable claw). A scorpion has darkened or granular raised linear ridges, called "keels" or "carinae" on the pedipalp segments and on other parts of the body; these are useful as taxonomic characters . Unlike those of some other arachnids, the legs have not been modified for other purposes, though they may occasionally be used for digging, and females may use them to catch emerging young. The legs are covered in proprioceptors , bristles and sensory setae . Depending on
10902-594: The body outward) are coxa, trochanter, femur, patella, tibia (including the fixed claw and the manus) and tarsus (moveable claw). A scorpion has darkened or granular raised linear ridges, called "keels" or "carinae" on the pedipalp segments and on other parts of the body; these are useful as taxonomic characters . Unlike those of some other arachnids, the legs have not been modified for other purposes, though they may occasionally be used for digging, and females may use them to catch emerging young. The legs are covered in proprioceptors , bristles and sensory setae . Depending on
11040-458: The chamber to refill. The 7th and last somite does not bear appendages or any other significant external structures. The mesosoma contains the heart or "dorsal vessel" which is the center of the scorpion's open circulatory system . The heart is continuous with a deep arterial system which spreads throughout the body. Sinuses return deoxygenated blood ( hemolymph ) to the heart; the blood is re-oxygenated by cardiac pores. The mesosoma also contains
11178-456: The chamber to refill. The 7th and last somite does not bear appendages or any other significant external structures. The mesosoma contains the heart or "dorsal vessel" which is the center of the scorpion's open circulatory system . The heart is continuous with a deep arterial system which spreads throughout the body. Sinuses return deoxygenated blood ( hemolymph ) to the heart; the blood is re-oxygenated by cardiac pores. The mesosoma also contains
11316-401: The claws, particularly by large-clawed species. Larger and more aggressive prey is given a sting. Scorpions, like other arachnids, digest their food externally. The chelicerae, which are very sharp, are used to pull small amounts of food off the prey item into a pre-oral cavity below the chelicerae and carapace. The digestive juices from the gut are egested onto the food, and the digested food
11454-399: The claws, particularly by large-clawed species. Larger and more aggressive prey is given a sting. Scorpions, like other arachnids, digest their food externally. The chelicerae, which are very sharp, are used to pull small amounts of food off the prey item into a pre-oral cavity below the chelicerae and carapace. The digestive juices from the gut are egested onto the food, and the digested food
11592-527: The corresponding astrological sign is Scorpio . A classical myth about Scorpius tells how the giant scorpion and its enemy Orion became constellations on opposite sides of the sky. The word scorpion originated in Middle English between 1175 and 1225 AD from Old French scorpion , or from Italian scorpione , both derived from the Latin scorpio , equivalent to scorpius , which
11730-416: The costs and benefits involved. A bird foraging for insects spends a lot of time searching but capturing and eating them is quick and easy, so the efficient strategy for the bird is to eat every palatable insect it finds. By contrast, a predator such as a lion or falcon finds its prey easily but capturing it requires a lot of effort. In that case, the predator is more selective. One of the factors to consider
11868-707: The cycles observed in lynx and snowshoe hares. One way of classifying predators is by trophic level . Carnivores that feed on herbivores are secondary consumers; their predators are tertiary consumers, and so forth. At the top of this food chain are apex predators such as lions . Many predators however eat from multiple levels of the food chain; a carnivore may eat both secondary and tertiary consumers. This means that many predators must contend with intraguild predation , where other predators kill and eat them. For example, coyotes compete with and sometimes kill gray foxes and bobcats . Chactoidea see Taxonomy Scorpions are predatory arachnids of
12006-993: The eggs hatch into larvae, which eat the host, and it inevitably dies. Zoologists generally call this a form of parasitism , though conventionally parasites are thought not to kill their hosts. A predator can be defined to differ from a parasitoid in that it has many prey, captured over its lifetime, where a parasitoid's larva has just one, or at least has its food supply provisioned for it on just one occasion. There are other difficult and borderline cases. Micropredators are small animals that, like predators, feed entirely on other organisms; they include fleas and mosquitoes that consume blood from living animals, and aphids that consume sap from living plants. However, since they typically do not kill their hosts, they are now often thought of as parasites. Animals that graze on phytoplankton or mats of microbes are predators, as they consume and kill their food organisms, while herbivores that browse leaves are not, as their food plants usually survive
12144-404: The evolution of mimicry. Avoidance is not necessarily an evolutionary response as it is generally learned from bad experiences with prey. However, when the prey is capable of killing the predator (as can a coral snake with its venom), there is no opportunity for learning and avoidance must be inherited. Predators can also respond to dangerous prey with counter-adaptations. In western North America,
12282-431: The extreme changes in temperature from day to night or between seasons; Pectinibuthus birulai lives in a temperature range of −30–50 °C (−22–122 °F). Scorpions that live outside deserts prefer lower temperatures. The ability to resist cold may be related to the increase in the sugar trehalose when the temperature drops. Some species hibernate . Scorpions appear to have resistance to ionizing radiation . This
12420-430: The extreme changes in temperature from day to night or between seasons; Pectinibuthus birulai lives in a temperature range of −30–50 °C (−22–122 °F). Scorpions that live outside deserts prefer lower temperatures. The ability to resist cold may be related to the increase in the sugar trehalose when the temperature drops. Some species hibernate . Scorpions appear to have resistance to ionizing radiation . This
12558-600: The eyes. Some Ananteris species can shed parts of their tail to escape predators. The parts do not grow back, leaving them unable to sting and defecate, but they can still catch small prey and reproduce for at least eight months afterward. Scorpions generally prey on insects, particularly grasshoppers , crickets , termites , beetles and wasps . Other prey include spiders, solifugids , woodlice and even small vertebrates including lizards, snakes and mammals. Species with large claws may prey on earthworms and mollusks. The majority of species are opportunistic and consume
12696-598: The eyes. Some Ananteris species can shed parts of their tail to escape predators. The parts do not grow back, leaving them unable to sting and defecate, but they can still catch small prey and reproduce for at least eight months afterward. Scorpions generally prey on insects, particularly grasshoppers , crickets , termites , beetles and wasps . Other prey include spiders, solifugids , woodlice and even small vertebrates including lizards, snakes and mammals. Species with large claws may prey on earthworms and mollusks. The majority of species are opportunistic and consume
12834-427: The female cares for the young as their exoskeletons harden, transporting them on her back. The exoskeleton contains fluorescent chemicals and glows under ultraviolet light. The vast majority of species do not seriously threaten humans, and healthy adults usually do not need medical treatment after a sting. About 25 species (fewer than one percent ) have venom capable of killing a human, which happens frequently in
12972-431: The larvae of coccinellid beetles (ladybirds) , alternate between actively searching and scanning the environment. Prey distributions are often clumped, and predators respond by looking for patches where prey is dense and then searching within patches. Where food is found in patches, such as rare shoals of fish in a nearly empty ocean, the search stage requires the predator to travel for a substantial time, and to expend
13110-722: The late 19th century in Sheerness in England at 51°N, while Paruroctonus boreus lives as far north as Red Deer, Alberta , at 52°N. A few species are on the IUCN Red List ; Lychas braueri is classed as critically endangered (2014), Isometrus deharvengi as endangered (2016) and Chiromachus ochropus as vulnerable (2014). Scorpions are xerocoles , meaning they primarily live in deserts , but they can be found in virtually every terrestrial habitat including high-elevation mountains, caves, and intertidal zones . They are largely absent from boreal ecosystems such as
13248-429: The light signals of other species, thereby attracting male fireflies, which they capture and eat. Flower mantises are ambush predators; camouflaged as flowers, such as orchids , they attract prey and seize it when it is close enough. Frogfishes are extremely well camouflaged, and actively lure their prey to approach using an esca , a bait on the end of a rod-like appendage on the head, which they wave gently to mimic
13386-612: The modern clades Chactoidea and Buthoidea respectively, indicating that the crown group of modern scorpions had emerged by this time. The Scorpiones are a clade within the pulmonate Arachnida (those with book lungs). Arachnida is placed within the Chelicerata , a subphylum of Arthropoda that contains sea spiders and horseshoe crabs , alongside terrestrial animals without book lungs such as ticks and harvestmen . The extinct Eurypterida , sometimes called sea scorpions, though they were not all marine, are not scorpions; their grasping pincers were chelicerae , not homologous with
13524-519: The most basal such as Eramoscorpius were likely still aquatic. Over 100 fossil species of scorpion have been described. The oldest found as of 2021 is Dolichophonus loudonensis , which lived during the Silurian, in present-day Scotland. Gondwanascorpio from the Devonian is among the earliest-known terrestrial animals on the Gondwana supercontinent. Some Palaeozoic scorpions possessed compound eyes similar to those of eurypterids. The Triassic fossils Protochactas and Protobuthus belong to
13662-483: The order Scorpiones in 1837. He divided it into four families, the six-eyed scorpions "Scorpionides", the eight-eyed scorpions "Buthides", the ten-eyed scorpions "Centrurides", and the twelve-eyed scorpions "Androctonides". More recently, some twenty-two families containing over 2,500 species of scorpions have been described, with many additions and much reorganization of taxa in the 21st century. There are over 100 described taxa of fossil scorpions. This classification
13800-478: The order Scorpiones in 1837. He divided it into four families, the six-eyed scorpions "Scorpionides", the eight-eyed scorpions "Buthides", the ten-eyed scorpions "Centrurides", and the twelve-eyed scorpions "Androctonides". More recently, some twenty-two families containing over 2,500 species of scorpions have been described, with many additions and much reorganization of taxa in the 21st century. There are over 100 described taxa of fossil scorpions. This classification
13938-434: The other hand, the fitness cost of a given lost dinner is unpredictable, as the predator may quickly find better prey. In addition, most predators are generalists, which reduces the impact of a given prey adaption on a predator. Since specialization is caused by predator-prey coevolution, the rarity of specialists may imply that predator-prey arms races are rare. It is difficult to determine whether given adaptations are truly
14076-504: The other three are dubious names. He placed the scorpions among his "Insecta aptera" (wingless insects), a group that included Crustacea, Arachnida and Myriapoda . In 1801, Jean-Baptiste Lamarck divided up the "Insecta aptera", creating the taxon Arachnides for spiders, scorpions, and acari (mites and ticks), though it also contained the Thysanura , Myriapoda and parasites such as lice. German arachnologist Carl Ludwig Koch created
14214-446: The other three are dubious names. He placed the scorpions among his "Insecta aptera" (wingless insects), a group that included Crustacea, Arachnida and Myriapoda . In 1801, Jean-Baptiste Lamarck divided up the "Insecta aptera", creating the taxon Arachnides for spiders, scorpions, and acari (mites and ticks), though it also contained the Thysanura , Myriapoda and parasites such as lice. German arachnologist Carl Ludwig Koch created
14352-468: The parts of the world where they live, primarily where access to medical treatment is unlikely. Scorpions appear in art, folklore, mythology, and commercial brands. Scorpion motifs are woven into kilim carpets for protection from their sting. Scorpius is the name of a constellation; the corresponding astrological sign is Scorpio . A classical myth about Scorpius tells how the giant scorpion and its enemy Orion became constellations on opposite sides of
14490-621: The pincers (second appendages) of scorpions. Scorpiones is sister to the Tetrapulmonata , a terrestrial group of pulmonates containing the spiders and whip scorpions. This 2019 cladogram summarizes: Pycnogonida (sea spiders) [REDACTED] Xiphosura (horseshoe crabs) [REDACTED] † Eurypterida (sea scorpions) [REDACTED] ( ticks , harvestmen , etc) [REDACTED] [REDACTED] Araneae (spiders) [REDACTED] Pedipalpi ( whip scorpions , etc) [REDACTED] Recent studies place pseudoscorpions as
14628-556: The pincers (second appendages) of scorpions. Scorpiones is sister to the Tetrapulmonata , a terrestrial group of pulmonates containing the spiders and whip scorpions. This 2019 cladogram summarizes: Pycnogonida (sea spiders) [REDACTED] Xiphosura (horseshoe crabs) [REDACTED] † Eurypterida (sea scorpions) [REDACTED] ( ticks , harvestmen , etc) [REDACTED] [REDACTED] Araneae (spiders) [REDACTED] Pedipalpi ( whip scorpions , etc) [REDACTED] Recent studies place pseudoscorpions as
14766-546: The poles and equator, though scorpions are found in the tropics. Scorpions did not occur naturally in Great Britain but were accidentally introduced by humans, and have now established a population. New Zealand , and some of the islands in Oceania , have in the past had small populations of introduced scorpions, but they were exterminated. Five colonies of Euscorpius flavicaudis have established themselves since
14904-538: The prey an opportunity to escape. Some frogs wait until snakes have begun their strike before jumping, reducing the time available to the snake to recalibrate its attack, and maximising the angular adjustment that the snake would need to make to intercept the frog in real time. Ballistic predators include insects such as dragonflies, and vertebrates such as archerfish (attacking with a jet of water), chameleons (attacking with their tongues), and some colubrid snakes . In pursuit predation, predators chase fleeing prey. If
15042-549: The prey are dense and mobile, and the predator has low energy requirements. Wide foraging expends more energy, and is used when prey is sedentary or sparsely distributed. There is a continuum of search modes with intervals between periods of movement ranging from seconds to months. Sharks, sunfish , Insectivorous birds and shrews are almost always moving while web-building spiders, aquatic invertebrates, praying mantises and kestrels rarely move. In between, plovers and other shorebirds , freshwater fish including crappies , and
15180-413: The prey flees in a straight line, capture depends only on the predator's being faster than the prey. If the prey manoeuvres by turning as it flees, the predator must react in real time to calculate and follow a new intercept path, such as by parallel navigation , as it closes on the prey. Many pursuit predators use camouflage to approach the prey as close as possible unobserved ( stalking ) before starting
15318-428: The prey's body. However, the "life-dinner" principle of Dawkins and Krebs predicts that this arms race is asymmetric: if a predator fails to catch its prey, it loses its dinner, while if it succeeds, the prey loses its life. The metaphor of an arms race implies ever-escalating advances in attack and defence. However, these adaptations come with a cost; for instance, longer legs have an increased risk of breaking, while
15456-433: The prey, given that the attack is not modifiable once launched. Ballistic interception is the strategy where a predator observes the movement of a prey, predicts its motion, works out an interception path, and then attacks the prey on that path. This differs from ambush predation in that the predator adjusts its attack according to how the prey is moving. Ballistic interception involves a brief period for planning, giving
15594-497: The prey. If the attack is successful, the predator kills the prey, removes any inedible parts like the shell or spines, and eats it. Predators are adapted and often highly specialized for hunting, with acute senses such as vision , hearing , or smell . Many predatory animals , both vertebrate and invertebrate , have sharp claws or jaws to grip, kill, and cut up their prey. Other adaptations include stealth and aggressive mimicry that improve hunting efficiency. Predation has
15732-509: The price of increased expenditure of energy to catch it, and increased risk that the prey will escape. Ambush predators are often solitary to reduce the risk of becoming prey themselves. Of 245 terrestrial members of the Carnivora (the group that includes the cats, dogs, and bears), 177 are solitary; and 35 of the 37 wild cats are solitary, including the cougar and cheetah. However, the solitary cougar does allow other cougars to share in
15870-414: The pursuit. Pursuit predators include terrestrial mammals such as humans, African wild dogs, spotted hyenas and wolves; marine predators such as dolphins, orcas and many predatory fishes, such as tuna; predatory birds (raptors) such as falcons; and insects such as dragonflies . An extreme form of pursuit is endurance or persistence hunting , in which the predator tires out the prey by following it over
16008-402: The reproductive system. The female gonads are made of three or four tubes that run parallel to each other and are connected by two to four transverse anastomoses . These tubes are the sites for both oocyte formation and embryonic development. They connect to two oviducts which connect to a single atrium leading to the genital orifice. Males have two gonads made of two cylindrical tubes with
16146-401: The reproductive system. The female gonads are made of three or four tubes that run parallel to each other and are connected by two to four transverse anastomoses . These tubes are the sites for both oocyte formation and embryonic development. They connect to two oviducts which connect to a single atrium leading to the genital orifice. Males have two gonads made of two cylindrical tubes with
16284-470: The result of coevolution, where a prey adaptation gives rise to a predator adaptation that is countered by further adaptation in the prey. An alternative explanation is escalation , where predators are adapting to competitors, their own predators or dangerous prey. Apparent adaptations to predation may also have arisen for other reasons and then been co-opted for attack or defence. In some of the insects preyed on by bats, hearing evolved before bats appeared and
16422-550: The same shelter; bark scorpions may aggregate up to 30 individuals. In some species, families of females and young sometimes aggregate. Scorpions prefer areas where the temperature remains in the range of 11–40 °C (52–104 °F), but may survive temperatures from well below freezing to desert heat. Scorpions can withstand intense heat: Leiurus quinquestriatus , Scorpio maurus and Hadrurus arizonensis can live in temperatures of 45–50 °C (113–122 °F) if they are sufficiently hydrated. Desert species must deal with
16560-547: The same shelter; bark scorpions may aggregate up to 30 individuals. In some species, families of females and young sometimes aggregate. Scorpions prefer areas where the temperature remains in the range of 11–40 °C (52–104 °F), but may survive temperatures from well below freezing to desert heat. Scorpions can withstand intense heat: Leiurus quinquestriatus , Scorpio maurus and Hadrurus arizonensis can live in temperatures of 45–50 °C (113–122 °F) if they are sufficiently hydrated. Desert species must deal with
16698-478: The sister group of scorpions in the clade Panscorpiones, which together with Tetrapulmonata makes up the clade Arachnopulmonata. The internal phylogeny of the scorpions has been debated, but genomic analysis consistently places the Bothriuridae as sister to a clade consisting of Scorpionoidea and Chactoidea . The scorpions diversified between the Devonian and the early Carboniferous . The main division
16836-416: The sister group of scorpions in the clade Panscorpiones, which together with Tetrapulmonata makes up the clade Arachnopulmonata. The internal phylogeny of the scorpions has been debated, but genomic analysis consistently places the Bothriuridae as sister to a clade consisting of Scorpionoidea and Chactoidea . The scorpions diversified between the Devonian and the early Carboniferous . The main division
16974-550: The sky. The word scorpion originated in Middle English between 1175 and 1225 AD from Old French scorpion , or from Italian scorpione , both derived from the Latin scorpio , equivalent to scorpius , which is the romanization of the Greek σκορπίος – skorpíos , with no native IE etymology (cfr. Arabic ʕaqrab 'scorpion', Proto-Germanic *krabbô 'crab'). Scorpion fossils have been found in many strata , including marine Silurian and estuarine Devonian deposits, coal deposits from
17112-417: The specialized tongue of the chameleon, with its ability to act like a projectile, is useless for lapping water, so the chameleon must drink dew off vegetation. The "life-dinner" principle has been criticized on multiple grounds. The extent of the asymmetry in natural selection depends in part on the heritability of the adaptive traits. Also, if a predator loses enough dinners, it too will lose its life. On
17250-408: The species, the legs may have spines and spurs. The mesosoma or preabdomen is the broad part of the opisthosoma. In the early stages of embryonic development the mesosoma consist of eight segments, but the first segment disappear before birth, so the mesosoma in scorpions actually consist of segments 2-8. These anterior seven somites (segments) of the opisthosoma are each covered dorsally by
17388-403: The species, the legs may have spines and spurs. The mesosoma or preabdomen is the broad part of the opisthosoma. In the early stages of embryonic development the mesosoma consist of eight segments, but the first segment disappear before birth, so the mesosoma in scorpions actually consist of segments 2-8. These anterior seven somites (segments) of the opisthosoma are each covered dorsally by
17526-422: The species. There are thus four pairs of book lungs; each consists of some 140 to 150 thin lamellae filled with air inside a pulmonary chamber, connected on the ventral side to an atrial chamber which opens into a spiracle. Bristles hold the lamellae apart. A muscle opens the spiracle and widens the atrial chamber; dorsoventral muscles contract to compress the pulmonary chamber, forcing air out, and relax to allow
17664-420: The species. There are thus four pairs of book lungs; each consists of some 140 to 150 thin lamellae filled with air inside a pulmonary chamber, connected on the ventral side to an atrial chamber which opens into a spiracle. Bristles hold the lamellae apart. A muscle opens the spiracle and widens the atrial chamber; dorsoventral muscles contract to compress the pulmonary chamber, forcing air out, and relax to allow
17802-515: The stinger to a position where it can strike again. Leiurus quinquestriatus can whip its tail at a speed of up to 128 cm/s (50 in/s) in a defensive strike. Scorpions may be attacked by other arthropods like ants, spiders, solifugids and centipedes . Major predators include frogs, lizards, snakes, birds, and mammals. Meerkats are somewhat specialized in preying on scorpions, biting off their stingers and being immune to their venom. Other predators adapted for hunting scorpions include
17940-511: The stinger to a position where it can strike again. Leiurus quinquestriatus can whip its tail at a speed of up to 128 cm/s (50 in/s) in a defensive strike. Scorpions may be attacked by other arthropods like ants, spiders, solifugids and centipedes . Major predators include frogs, lizards, snakes, birds, and mammals. Meerkats are somewhat specialized in preying on scorpions, biting off their stingers and being immune to their venom. Other predators adapted for hunting scorpions include
18078-480: The substrate. Males begin courtship by moving their bodies back and forth, without moving the legs, a behavior known as juddering. This appears to produce ground vibrations that are picked up by the female. Predatory Predation is a biological interaction where one organism, the predator , kills and eats another organism, its prey . It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill
18216-684: The target of an attack, for example, by signalling that they are toxic or unpalatable , by signalling that a chase would be unprofitable, or by forming groups. If they become a target, they can try to fend off the attack with defences such as armour, quills , unpalatability, or mobbing; and they can often escape an attack in progress by startling the predator, playing dead , shedding body parts such as tails, or simply fleeing. Predators and prey are natural enemies, and many of their adaptations seem designed to counter each other. For example, bats have sophisticated echolocation systems to detect insects and other prey, and insects have developed
18354-478: The top of the cephalothorax, and usually two to five pairs of eyes along the front corners of the cephalothorax. While unable to form sharp images, their central eyes are amongst the most light sensitive in the animal kingdom, especially in dim light, which makes it possible for nocturnal species to use starlight to navigate at night. The chelicerae are at the front and underneath the carapace. They are pincer-like and have three segments and sharp "teeth". The brain of
18492-475: The top of the cephalothorax, and usually two to five pairs of eyes along the front corners of the cephalothorax. While unable to form sharp images, their central eyes are amongst the most light sensitive in the animal kingdom, especially in dim light, which makes it possible for nocturnal species to use starlight to navigate at night. The chelicerae are at the front and underneath the carapace. They are pincer-like and have three segments and sharp "teeth". The brain of
18630-533: The tropics. Scorpions did not occur naturally in Great Britain but were accidentally introduced by humans, and have now established a population. New Zealand , and some of the islands in Oceania , have in the past had small populations of introduced scorpions, but they were exterminated. Five colonies of Euscorpius flavicaudis have established themselves since the late 19th century in Sheerness in England at 51°N, while Paruroctonus boreus lives as far north as Red Deer, Alberta , at 52°N. A few species are on
18768-568: Was discovered in the early 1960s when scorpions were found to be among the few animals to survive nuclear tests at Reggane , Algeria. Desert scorpions have several adaptations for water conservation. They excrete insoluble compounds such as xanthine , guanine , and uric acid , not requiring water for their removal from the body. Guanine is the main component and maximizes the amount of nitrogen excreted. A scorpion's cuticle holds in moisture via lipids and waxes from epidermal glands, and protects against ultraviolet radiation . Even when dehydrated,
18906-567: Was discovered in the early 1960s when scorpions were found to be among the few animals to survive nuclear tests at Reggane , Algeria. Desert scorpions have several adaptations for water conservation. They excrete insoluble compounds such as xanthine , guanine , and uric acid , not requiring water for their removal from the body. Guanine is the main component and maximizes the amount of nitrogen excreted. A scorpion's cuticle holds in moisture via lipids and waxes from epidermal glands, and protects against ultraviolet radiation . Even when dehydrated,
19044-401: Was used to hear signals used for territorial defence and mating. Their hearing evolved in response to bat predation, but the only clear example of reciprocal adaptation in bats is stealth echolocation. A more symmetric arms race may occur when the prey are dangerous, having spines, quills, toxins or venom that can harm the predator. The predator can respond with avoidance, which in turn drives
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