112-530: Agkistrodon contortrix (the copperhead, a snake ), Dinemellia dinemelli (the white-faced buffalo-weaver, a bird ), various extinct ornithischian dinosaurs , Chelonia mydas (the green sea turtle ), Anurognathus (an extinct pterosaur ), and Alligator mississippiensis (the american alligator, a crocodilian ) Sauria is the clade of diapsids containing the most recent common ancestor of Archosauria (which includes crocodilians and birds ) and Lepidosauria (which includes squamates and
224-463: A camouflage pile. Eastern copperheads breed in late summer, but not every year; sometimes, females produce young for several years running, then do not breed at all for a time. Mating is sometimes preceded by male combat. Females give birth to live young, each of which is about 20 cm (8 in) in total length. The typical litter size is four to seven, but as few as one, or as many as 20 may be seen. Females are capable of storing sperm for up to
336-574: A bony secondary palate which completely separates the oral and nasal cavities. The necks of turtles are highly flexible, possibly to compensate for their rigid shells. Some species, like sea turtles, have short necks while others, such as snake-necked turtles , have long ones. Despite this, all turtle species have eight neck vertebrae , a consistency not found in other reptiles but similar to mammals . Some snake-necked turtles have both long necks and large heads, limiting their ability to lift them when not in water. Some turtles have folded structures in
448-635: A brightly colored tail to attract frogs and perhaps lizards, a behavior termed caudal luring (see video: [1] ). Sight, odor, and heat detection are used in locating prey, although after the prey has been envenomated, odor and taste become the primary means of tracking. Smaller prey items and birds are often seized and held in the mouth until dead, while larger prey items are typically bitten, released, and then tracked until dead. Copperheads occasionally feed on carrion. Gravid females typically fast, although some individuals occasionally take small volumes of food. An individual may eat up to twice its body mass in
560-467: A darker brown or black within one year. Adults grow to a typical length (including tail) of 50–95 cm (20–37 in). In most of North America, the eastern copperhead favors deciduous forest and mixed woodlands. It may occupy rock outcroppings and ledges, but is also found in low-lying, swampy regions. During the winter, it hibernates in dens or limestone crevices, often together with timber rattlesnakes and black rat snakes . The eastern copperhead
672-513: A hot day, and to fall naturally to around 29 °C (84 °F) by night. Some giant tortoises seek out shade to avoid overheating on sunny days. On Grand Terre Island , food is scarce inland, shade is scarce near the coast, and the tortoises compete for space under the few trees on hot days. Large males may push smaller females out of the shade, and some then overheat and die. Adult sea turtles, too, have large enough bodies that they can to some extent control their temperature. The largest turtle,
784-446: A mean of roughly 197.4 g ( 6 + 15 ⁄ 16 oz). Females do not typically exceed 60 to 66 cm ( 23 + 1 ⁄ 2 to 26 in), and have a mean body mass of 119.8 g ( 4 + 7 ⁄ 32 oz). The maximum length reported for this species is 134.6 cm (53 in) for A. c. mokasen (Ditmars, 1931). Brimley (1944) mentions a specimen of A. c. mokasen from Chapel Hill, North Carolina , that
896-416: A propulsive force twice as large, and swim six times as fast, as freshwater turtles. The swimming efficiency of young marine turtles is similar to that of fast-swimming fish of open water, like mackerel . Compared to other reptiles, turtles tend to have reduced tails, but these vary in both length and thickness among species and between sexes. Snapping turtles and the big-headed turtle have longer tails;
1008-698: A sexual mode of reproduction to an asexual mode. The type of parthenogenesis that likely occurs is automixis with terminal fusion , a process in which two terminal products from the same meiosis fuse to form a diploid zygote. This process leads to genome-wide homozygosity , expression of deleterious recessive alleles, and often to developmental failure ( inbreeding depression ). Both captive-born and wild-born A. contortrix snakes appear to be capable of this form of parthenogenesis. Although venomous, eastern copperheads are generally not aggressive and bites are rarely fatal. Copperhead venom has an estimated lethal dose around 100 mg, and tests on mice show its potency
1120-404: A softshell turtle may dive underwater and bury itself under the sea floor. If a predator persists, the turtle may bite or discharge from its cloaca. Several species produce foul-smelling chemicals from musk glands. Other tactics include threat displays and Bell's hinge-back tortoise can play dead . When attacked, big-headed turtle hatchlings squeal, possibly startling the predator. Turtles are
1232-461: A species may change with age, sex, and season, and may also differ between populations. In many species, juveniles are generally carnivorous but become more herbivorous as adults. With Barbour's map turtle , the larger female mainly eats mollusks while the male usually eats arthropods . Blanding's turtle may feed mainly on snails or crayfish depending on the population. The European pond turtle has been recorded as being mostly carnivorous much of
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#17327733921391344-401: A specific area, such as a beach, leaving the eggs to hatch unattended. The young turtles leave that area, migrating long distances in the years or decades in which they grow to maturity, and then return seemingly to the same area every few years to mate and lay eggs, though the precision varies between species and populations. This "natal homing" has appeared remarkable to biologists, though there
1456-419: A turtle is unique among vertebrates and serves to protect the animal and provide shelter from the elements. It is primarily made of 50–60 bones and consists of two parts: the domed, dorsal (back) carapace and the flatter, ventral (belly) plastron . They are connected by lateral (side) extensions of the plastron. The carapace is fused with the vertebrae and ribs while the plastron is formed from bones of
1568-450: A worm-like appendage on its tongue that it uses to lure fish into its mouth. Tortoises are the most herbivorous group, consuming grasses, leaves, and fruits. Many turtle species, including tortoises, supplement their diet with eggshells, animal bones, hair, and droppings for extra nutrients. Turtles generally eat their food in a straightforward way, though some species have special feeding techniques. The yellow-spotted river turtle and
1680-571: A year. Their size apart, the young are similar to the adults, but lighter in color, and with a yellowish-green-marked tip to the tail, which is used to lure lizards and frogs. A. contortrix males have longer tongue tie lengths than females during the breeding season, which may aid in chemoreception of males searching for females. Parthenogenesis is a natural form of reproduction in which growth and development of embryos occur without fertilization. A. contortrix can reproduce by facultative parthenogenesis, that is, they are capable of switching from
1792-410: A year. One study found an individual that ate eight times during an annual activity period, totaling 1.25 times its body mass. Predators of the eastern copperhead are not well known, but may include owls, hawks, opossums, bullfrogs, and other snakes. They will use anti-predatory behaviors to discourage predators. These include: move away or flee, musking, tail vibrating, mouth gaping, or curling up into
1904-501: Is "Carolina". Schmidt (1953) proposed the type locality be restricted to "Charleston, South Carolina". Unlike some other species of North American pit vipers, such as the timber rattlesnake and massasauga , the copperhead has mostly not re-established itself north of the terminal moraine after the last glacial period (the Wisconsin glaciation ), though it is found in southeastern New York and southern New England , north of
2016-898: Is a regional variant of A. c. laticinctus . Five subspecies have been recognized in the past, but recent genetic analysis shows that A c. contorix and two of the subspecies are monotypic, while Agkistrodon laticinctus (formerly Agkistrodon contortrix laticinctus ) and the fifth subspecies are a single distinct species. Agkistrodon contortrix contortrix ( Linnaeus , 1766) Agkistrodon contortrix ( Linnaeus , 1766) Agkistrodon contortrix laticinctus Gloyd & Conant , 1934 Agkistrodon laticinctus Gloyd & Conant , 1934 Agkistrodon contortrix mokasen Palisot de Beauvois , 1799 Agkistrodon contortrix Agkistrodon contortrix phaeogaster Gloyd, 1969 Agkistrodon contortrix Agkistrodon contortrix pictigaster Gloyd & Conant, 1943 Agkistrodon laticinctus Testudines Turtles are reptiles of
2128-412: Is also present on the flanks, next to the belly, and are largest and darkest in the spaces between the crossbands. The belly is the same color as the ground color, but may be a little whitish in part. At the base of the tail are one to three (usually two) brown crossbands followed by a gray area. In juveniles, the pattern on the tail is more distinct: 7–9 crossbands are visible, while the tip is yellow. On
2240-458: Is among the lowest of all pit vipers, and slightly weaker than that of its close relative, the cottonmouth . Copperheads often employ a "warning bite" when stepped on or agitated and inject a relatively small amount of venom, if any at all. "Dry bites" involving no venom are particularly common with the copperhead, though all pit vipers are capable of a dry bite. The fangs of dead pit vipers are capable of delivering venom in amounts that necessitate
2352-554: Is classified as least concern on the IUCN Red List of Threatened Species (v3.1, 2001). This means that relative to many other species, it is not at risk of extinction in the near future. The population trend was stable when assessed in 2007. Their venom has potential medicinal value to humans. In the Southern United States , copperheads are nocturnal during the hot summer, but are commonly active during
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#17327733921392464-504: Is experimental evidence that the embryos of Mauremys reevesii can move around inside their eggs to select the best temperature for development, thus influencing their sexual destiny. In other species, sex is determined genetically . The length of incubation for turtle eggs varies from two to three months for temperate species, and four months to over a year for tropical species. Species that live in warm temperate climates can delay their development . Hatching young turtles break out of
2576-539: Is high during this period but significantly decreases when they reach adulthood. Most species grow quickly during their early years and slow down when they mature. Turtles can live long lives. The oldest living turtle and land animal is said to be a Seychelles giant tortoise named Jonathan , who turned 187 in 2019. A Galápagos tortoise named Harriet was collected by Charles Darwin in 1835; it died in 2006, having lived for at least 176 years. Most wild turtles do not reach that age. Turtles keep growing new scutes under
2688-399: Is highest in a horizontal band with retinal cells packed about twice as densely as elsewhere. This gives the best vision along the visual horizon. Sea turtles do not appear to use polarized light for orientation as many other animals do. The deep-diving leatherback turtle lacks specific adaptations to low light, such as large eyes, large lenses, or a reflective tapetum . It may rely on seeing
2800-400: Is important in some species, and female green sea turtles are not always receptive. As such, they have evolved behaviors to avoid the male's attempts at copulation, such as swimming away, confronting the male followed by biting or taking up a refusal position with her body vertical, her limbs widely outspread, and her plastron facing the male. If the water is too shallow for the refusal position,
2912-574: Is known to feed on a wide variety of prey, including invertebrates (primarily arthropods ) and vertebrates . Like most pit vipers, the eastern copperhead is generally an ambush predator; it takes up a promising position and waits for suitable prey to arrive. As a common species within its range, it may be encountered by humans. Unlike other viperids, it often "freezes" instead of slithering away and fleeing, due to its habit of relying on excellent camouflage. Bites occur due to people unknowingly stepping on or near them. Copperhead bites account for half of
3024-464: Is made. Like most other New World vipers, copperheads exhibit defensive tail vibration behavior when closely approached. This species is capable of vibrating its tail in excess of 40 times per second— faster than almost any other nonrattlesnake snake species. The eastern copperhead is a diet generalist and is known to feed on a wide variety of prey, including invertebrates (primarily arthropods ) and vertebrates . A generalized ontogenetic shift in
3136-477: Is now plentiful evidence for it, including from genetics. How sea turtles navigate to their breeding beaches remains unknown. One possibility is imprinting as in salmon , where the young learn the chemical signature, effectively the scent, of their home waters before leaving, and remember that when the time comes for them to return as adults. Another possible cue is the orientation of the Earth's magnetic field at
3248-426: Is often complex in aquatic species, both marine and freshwater, but simpler in the semi-aquatic mud turtles and snapping turtles. A male tortoise bobs his head, then subdues the female by biting and butting her before mounting. The male scorpion mud turtle approaches the female from the rear, and often resorts to aggressive methods such as biting the female's tail or hind limbs, followed by a mounting. Female choice
3360-453: Is possibly a fourth type of cone that detects ultraviolet , as hatchling sea turtles respond experimentally to ultraviolet light, but it is unknown if they can distinguish this from longer wavelengths. A freshwater turtle, the red-eared slider , has an exceptional seven types of cone cell. Sea turtles orient themselves on land by night, using visual features detected in dim light. They can use their eyes in clear surface water, muddy coasts,
3472-557: Is thickened and used for butting and ramming during combat. Shells vary in flexibility. Some species, such as box turtles , lack the lateral extensions and instead have the carapace bones fully fused or ankylosed together. Several species have hinges on their shells, usually on the plastron, which allow them to expand and contract. Softshell turtles have rubbery edges, due to the loss of bones. The leatherback turtle has hardly any bones in its shell, but has thick connective tissue and an outer layer of leathery skin. The turtle's skull
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3584-497: Is thought to prevent them from collapsing. During exhalation, the contraction of the transversus abdominis muscle propels the organs into the lungs and expels air. Conversely, during inhalation, the relaxing and flattening of the oblique abdominis muscle pulls the transversus back down, allowing air back into the lungs. Although many turtles spend large amounts of their lives underwater, all turtles breathe air and must surface at regular intervals to refill their lungs. Depending on
3696-551: Is unique among living amniotes (which includes reptiles, birds and mammals); it is solid and rigid with no openings for muscle attachment ( temporal fenestrae ). Muscles instead attach to recesses in the back of the skull. Turtle skulls vary in shape, from the long and narrow skulls of softshells to the broad and flattened skull of the mata mata . Some turtle species have developed large and thick heads, allowing for greater muscle mass and stronger bites. Turtles that are carnivorous or durophagous (eating hard-shelled animals) have
3808-562: Is usually interpreted to reference the distorted pattern of darker bands across the snake's back, which are broad at the lateral base, but "pinched" into narrow hourglass shapes in the middle at the vertebral area. Adults grow to a typical length (including tail) of 50–95 cm (20–37 in). Some may exceed 1 m (3 ft 3 in), although that is exceptional for this species. Males do not typically exceed 74 to 76 cm (29 to 30 in) and weigh from 101.5 to 343 g ( 3 + 9 ⁄ 16 to 12 + 1 ⁄ 8 oz), with
3920-510: The Ancient Greek word χελώνη ( chelone ) 'tortoise'. Testudines is the official order name due to the principle of priority . The term chelonian is used as a formal name for members of the group. The largest living species of turtle (and fourth-largest reptile ) is the leatherback turtle , which can reach over 2.7 m (8 ft 10 in) in length and weigh over 500 kg (1,100 lb). The largest known turtle
4032-853: The Late Cretaceous and Cenozoic , members of the pleurodire families Bothremydidae and Podocnemididae became widely distributed in the Northern Hemisphere due to their coastal habits. The oldest known soft-shelled turtles and sea turtles appeared during the Early Cretaceous . Tortoises originated in Asia during the Eocene . A late surviving group of stem-turtles, the Meiolaniidae , survived in Australasia into
4144-737: The Middle Triassic , and Eorhynchochelys of the Late Triassic lacked carapaces and plastrons but had shortened torsos, expanded ribs, and lengthened dorsal vertebrae. Also in the Late Triassic, Odontochelys had a partial shell consisting of a complete bony plastron and an incomplete carapace. The development of a shell reached completion with the Late Triassic Proganochelys , with its fully developed carapace and plastron. Adaptations that led to
4256-570: The bioluminescence of prey when hunting in deep water. Turtles have no ear openings; the eardrum is covered with scales and encircled by a bony otic capsule , which is absent in other reptiles. Their hearing thresholds are high in comparison to other reptiles, reaching up to 500 Hz in air, but underwater they are more attuned to lower frequencies. The loggerhead sea turtle has been shown experimentally to respond to low sounds, with maximal sensitivity between 100 and 400 Hz. Turtles have olfactory (smell) and vomeronasal receptors along
4368-403: The brackish -living diamondback terrapin secrete excess salt in a thick sticky substance from their tear glands . Because of this, sea turtles may appear to be "crying" when on land. Turtles, like other reptiles, have a limited ability to regulate their body temperature . This ability varies between species, and with body size. Small pond turtles regulate their temperature by crawling out of
4480-434: The copperhead , is a species of venomous snake , a pit viper , endemic to eastern North America; it is a member of the subfamily Crotalinae in the family Viperidae . The eastern copperhead has distinctive, dark brown, hourglass-shaped markings, overlaid on a light reddish brown or brown/gray background. The body type is heavy, rather than slender. Neonates are born with green or yellow tail tips, which progress to
4592-402: The coracoid . Both the shoulder and pelvic girdles of turtles are located within the shell and hence are effectively within the rib cage. The trunk ribs grow over the shoulder girdle during development. The shell is covered in epidermal (outer skin) scales known as scutes that are made of keratin , the same substance that makes up hair and fingernails. Typically, a turtle has 38 scutes on
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4704-596: The larynx or glottis that vibrate to produce sound. Other species have elastin -rich vocal cords . Due to their heavy shells, turtles are slow-moving on land. A desert tortoise moves at only 0.22–0.48 km/h (0.14–0.30 mph). By contrast, sea turtles can swim at 30 km/h (19 mph). The limbs of turtles are adapted for various means of locomotion and habits and most have five toes. Tortoises are specialized for terrestrial environments and have column-like legs with elephant-like feet and short toes. The gopher tortoise has flattened front limbs for digging in
4816-510: The order Testudines , characterized by a special shell developed mainly from their ribs. Modern turtles are divided into two major groups, the Pleurodira (side necked turtles) and Cryptodira (hidden necked turtles), which differ in the way the head retracts. There are 360 living and recently extinct species of turtles, including land-dwelling tortoises and freshwater terrapins . They are found on most continents, some islands and, in
4928-422: The painted turtle may filter feed by skimming the water surface with their mouth and throat open to collect particles of food. When the mouth closes, the throat constricts and water is pushed out through the nostrils and the gap in between the jaws. Some species employ a "gape-and-suck method" where the turtle opens its jaws and expands its throat widely, sucking the prey in. The diet of an individual within
5040-400: The pig-nosed turtle are the most specialized for swimming. Their front limbs have evolved into flippers while the shorter hind limbs are shaped more like rudders. The front limbs provide most of the thrust for swimming, while the hind limbs serve as stabilizers. Sea turtles such as the green sea turtle rotate the front limb flippers like a bird's wings to generate a propulsive force on both
5152-407: The shoulder girdle , sternum , and gastralia (abdominal ribs). During development, the ribs grow sideways into a carapacial ridge, unique to turtles, entering the dermis (inner skin) of the back to support the carapace. The development is signaled locally by proteins known as fibroblast growth factors that include FGF10 . The shoulder girdle in turtles is made up of two bones, the scapula and
5264-436: The tuatara ), and all its descendants. Since most molecular phylogenies recover turtles as more closely related to archosaurs than to lepidosaurs as part of Archelosauria , Sauria can be considered the crown group of diapsids, or reptiles in general. Depending on the systematics, Sauria includes all modern reptiles or most of them (including birds , a type of archosaur) as well as various extinct groups. Sauria lies within
5376-472: The "Polka Dot Ancestor" by Olivier Rieppel. The theory accounted for the evolution of fossil pareiasaurs from Bradysaurus to Anthodon , but not for how the ribs could have become attached to the bony dermal plates. More recent discoveries have painted a different scenario for the evolution of the turtle's shell. The stem -turtles Eunotosaurus of the Middle Permian , Pappochelys of
5488-502: The Wisconsin glaciation terminal moraine on Long Island . Eastern copperheads are habitat generalists which are species able to survive in different habitats (fragmented and unfragmented). Within its range, it occupies a variety of different habitats. In most of North America, it favors deciduous forest and mixed woodlands. It is often associated with rock outcroppings and ledges, but is also found in low-lying, swampy regions. During
5600-775: The analysis of Li et al . (2018). It places turtles within Diapsida but outside of Sauria (the Lepidosauromorpha + Archosauromorpha clade). † Parareptilia [REDACTED] † Captorhinidae [REDACTED] † Paleothyris [REDACTED] † Araeoscelidia [REDACTED] † Hovasaurus [REDACTED] † Youngina † Acerosodontosaurus † Claudiosaurus † Eunotosaurus † Pappochelys [REDACTED] † Eorhynchochelys [REDACTED] † Odontochelys Agkistrodon contortrix The eastern copperhead ( Agkistrodon contortrix ), also known simply as
5712-570: The availability of antivenom stated it used 1 Acp to 5 Acp depending on the symptoms and circumstances. Antivenom use however may not be necessary in the majority of cases, A study that analyzed 88 copperhead bite victims reported that all the victims survived and none required antivenom. This species was long considered to contain five subspecies listed below, but gene analysis suggests that A. c. laticinctus represents its own distinct species, while A. c. mokasen and A. c. phaeogaster are regional variants of A. c. contortrix , and A. c. pictigaster
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#17327733921395824-504: The back of the female's plastron. Aquatic turtles mount in water, and female sea turtles support the mounting male while swimming and diving. During copulation, the male turtle aligns his tail with the female's so he can insert his penis into her cloaca. Some female turtles can store sperm from multiple males and their egg clutches can have multiple sires. Turtles, including sea turtles, lay their eggs on land, although some lay eggs near water that rises and falls in level, submerging
5936-449: The carapace and 16 on the plastron, giving them 54 in total. Carapace scutes are divided into "marginals" around the margin and "vertebrals" over the vertebral column, though the scute that overlays the neck is called the "cervical". "Pleurals" are present between the marginals and vertebrals. Plastron scutes include gulars (throat), humerals, pectorals, abdominals, and anals. Side-necked turtles additionally have "intergular" scutes between
6048-404: The case of sea turtles , much of the ocean. Like other amniotes (reptiles, birds , and mammals ) they breathe air and do not lay eggs underwater, although many species live in or around water. Turtle shells are made mostly of bone ; the upper part is the domed carapace , while the underside is the flatter plastron or belly-plate. Its outer surface is covered in scales made of keratin ,
6160-408: The center, but darker towards the edges. They are about two scales wide or less at the midline of the back, but expand to a width of 6–10 scales on the sides of the body. They do not extend down to the ventral scales. Often, the crossbands are divided at the midline and alternate on either side of the body, with some individuals even having more half bands than complete ones. A series of dark brown spots
6272-509: The clade Sauria also help them be distinguished from stem-saurians in Diapsida or stem-reptiles in clade Sauropsida in the following categories based on the following regions of the body. However, some of these characters might be lost or modified in several lineages, particularly among birds and turtles; it is best to see these characters as the ancestral features that were present in the ancestral saurian. The cladogram shown below follows
6384-416: The crossbands were fused together longitudinally to form a continuous, undulating band, surmounted above by a dark stripe that was 2.0–2.5 scales wide. In another specimen, from Lowndes County, Alabama , the first three crossbands were complete, followed by a dark stripe that ran down either side of the body, with points of pigment reaching up to the midline in six places, but never getting there, after which
6496-436: The darkness of the deep ocean, and also above water. Unlike in terrestrial turtles, the cornea (the curved surface that lets light into the eye) does not help to focus light on the retina, so focusing underwater is handled entirely by the lens, behind the cornea. The cone cells contain oil droplets placed to shift perception toward the red part of the spectrum, improving color discrimination. Visual acuity, studied in hatchlings,
6608-478: The day during the spring and fall. Unlike other viperids, they often "freeze" instead of slithering away, and as a result, many bites occur due to people unknowingly stepping on or near them. This tendency to freeze most likely evolved because of the extreme effectiveness of their camouflage. When lying on dead leaves or red clay, they can be almost impossible to notice. They frequently stay still even when approached closely, and generally strike only if physical contact
6720-428: The diet include various invertebrates, e.g. millipedes ( Diplopoda ), spiders ( Arachnida ), beetles ( Coleoptera ), dragonflies ( Odonata ), grasshoppers ( Orthoptera ), and mantids ( Mantidae ), as well as numerous species of vertebrates, including salamanders, frogs, lizards, snakes, small turtles, small birds, young opossums, squirrels, chipmunks, rabbits, bats, shrews, moles, rats, and mice. Like most pit vipers,
6832-928: The diet occurs, with juveniles feeding on higher percentages of invertebrates and ectotherms , and adults feeding on a higher percentage vertebrate endotherms . Both juveniles and adults, though, feed on invertebrates and vertebrates opportunistically. The diet is also known to vary among geographic populations. Studies conducted at various locations within the range of the eastern copperhead ( A. contortrix ), including Tennessee, Kentucky , Kansas , and Texas , identified some consistently significant prey items included cicadas ( Tibicen ), caterpillars ( Lepidoptera ), lizards ( Sceloporus and Scincella ), voles ( Microtus ), and mice ( Peromyscus ). Accounts of finding large numbers of copperheads in bushes, vines, and trees seeking newly emerged cicadas, some as high as 40 feet above ground, have been reported from Texas by various herpetologists. Other items documented in
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#17327733921396944-462: The eastern copperhead is generally an ambush predator; it takes up a promising position and waits for suitable prey to arrive. One exception to ambush foraging occurs when copperheads feed on insects such as caterpillars and freshly molted cicadas. When hunting insects, copperheads actively pursue their prey. They possess facial pit organs which is a complex infrared-imaging system that allows accurate and precise strikes on potential prey. Juveniles use
7056-595: The eggs. While most species build nests and lay eggs where they forage, some travel miles. The common snapping turtle walks 5 km (3 mi) on land, while sea turtles travel even further; the leatherback swims some 12,000 km (7,500 mi) to its nesting beaches. Most turtles create a nest for their eggs. Females usually dig a flask-like chamber in the substrate. Other species lay their eggs in vegetation or crevices. Females choose nesting locations based on environmental factors such as temperature and humidity, which are important for developing embryos. Depending on
7168-450: The entire group. The name of the order, Testudines ( / t ɛ ˈ s tj uː d ɪ n iː z / teh- STEW -din-eez ), is based on the Latin word testudo 'tortoise'; and was coined by German naturalist August Batsch in 1788. The order has also been historically known as Chelonii ( Latreille 1800) and Chelonia (Ross and Macartney 1802), which are based on
7280-526: The environment using landmarks and a map-like system resulting in accurate direct routes towards a goal. Navigation in turtles have been correlated to high cognition function in the medial cortex region of the brain. When sensing danger, a turtle may flee, freeze or withdraw into its shell. Freshwater turtles flee into the water, though the Sonora mud turtle may take refuge on land as the shallow temporary ponds they inhabit make them vulnerable. When startled,
7392-784: The evolution of the shell may have originally been for digging and a fossorial lifestyle. The oldest known members of the Pleurodira lineage are the Platychelyidae , from the Late Jurassic . The oldest known unambiguous cryptodire is Sinaspideretes , a close relative of softshell turtles, from the Late Jurassic of China. Turtles became highly diverse during the Cretaceous, as climatic conditions in this period were favourable for their global dispersal. During
7504-530: The females resort to beaching themselves, as the males do not follow them ashore. All turtles fertilize internally; mounting and copulation can be difficult. In many species, males have a concave plastron that interlocks with the female's carapace. In species like the Russian tortoise , the male has a lighter shell and longer legs. The high, rounded shape of box turtles are particular obstacles for mounting. The male eastern box turtle leans backward and hooks onto
7616-471: The gulars. Turtle scutes are usually structured like mosaic tiles, but some species, like the hawksbill sea turtle , have overlapping scutes on the carapace. The shapes of turtle shells vary with the adaptations of the individual species, and sometimes with sex . Land-dwelling turtles are more dome-shaped, which appears to make them more resistant to being crushed by large animals. Aquatic turtles have flatter, smoother shells that allow them to cut through
7728-633: The head are insulated by fat around the neck. Most turtle species are opportunistic omnivores; land-dwelling species are more herbivorous and aquatic ones more carnivorous . Generally lacking speed and agility, most turtles feed either on plant material or on animals with limited movements like mollusks, worms, and insect larvae. Some species, such as the African helmeted turtle and snapping turtles, eat fish, amphibians, reptiles (including other turtles), birds, and mammals. They may take them by ambush but also scavenge. The alligator snapping turtle has
7840-453: The head are usually 9 large symmetrical plates, 6–10 (usually 8) supralabial scales , and 8–13 (usually 10) sublabial scales . The color pattern consists of a pale tan to pinkish-tan ground color that becomes darker towards the foreline, overlaid with a series of 10–18 (13.4) crossbands. Characteristically, both the ground color and crossband pattern are pale in A. c. contortrix . These crossbands are light tan to pinkish-tan to pale brown in
7952-500: The head, the crown is usually unmarked, except for a pair of small dark spots, one near the midline of each parietal scale . A faint postocular stripe is also present; diffuse above and bordered below by a narrow brown edge. Several aberrant color patterns for A. c. contortrix , or populations that intergrade with it, have also been reported. In a specimen described by Livezey (1949) from Walker County, Texas , 11 of 17 crossbands were not joined middorsally, while on one side, three of
8064-399: The laboratory, Florida red-bellied cooters can learn novel tasks and have demonstrated a long-term memory of at least 7.5 months. Similarly, giant tortoises can learn and remember tasks, and master lessons much faster when trained in groups. Tortoises appear to be able to retain operant conditioning nine years after their initial training. Studies have shown that turtles can navigate
8176-416: The larger total group Sauropsida , which also contains various stem -reptiles which are more closely related to reptiles than to mammals. Prior to its modern usage, "Sauria" was used as a name for the suborder occupied by lizards , which before 1800 were considered crocodilians. Sauria was historically used as a partial equivalent for Squamata (which contains lizards and snakes). The redefinition to cover
8288-510: The last common ancestor of archosaurs and lepidosaurs was the result of papers by Jacques A. Gauthier and colleagues in the 1980s. Genomic studies and comprehensive studies in the fossil record suggest that turtles are closely related to archosaurs as part of Sauria, and not to the non-saurian parareptiles as previously thought. In a 2018 cladistic analysis, Pantestudines (turtles and close relatives) were placed within Diapsida but outside of Sauria. The synapomorphies or characters that unite
8400-1025: The last four crossbands on the tail were also complete. A specimen found in Terrebonne Parish, Louisiana had a similar striped pattern, with only the first and last two crossbands being normal. The eastern copperhead is found in North America; its range within the United States is in Alabama , Arkansas , Connecticut , Delaware , Florida , Georgia , Illinois , Indiana , Iowa , Kansas , Kentucky , Louisiana , Maryland , Massachusetts , Mississippi , Missouri , Nebraska , New Jersey , New York , North Carolina , Ohio , Oklahoma , Pennsylvania , South Carolina , Tennessee , Texas , Virginia , and West Virginia . In Mexico , it occurs in Chihuahua and Coahuila . The type locality
8512-633: The latter uses it for balance while climbing. The cloaca is found underneath and at the base, and the tail itself houses the reproductive organs. Hence, males have longer tails to contain the penis. In sea turtles, the tail is longer and more prehensile in males, who use it to grasp mates. Several turtle species have spines on their tails. Turtles make use of vision to find food and mates, avoid predators, and orient themselves. The retina 's light-sensitive cells include both rods for vision in low light, and cones with three different photopigments for bright light, where they have full-color vision. There
8624-408: The leatherback, can swim in the waters off Nova Scotia , which may be as cold as 8 °C (46 °F), while their body temperature has been measured at up to 12 °C (22 °F) warmer than the surrounding water. To help keep their temperature up, they have a system of countercurrent heat exchange in the blood vessels between their body core and the skin of their flippers. The vessels supplying
8736-549: The lungs via the pulmonary artery , or to the body via the aorta . The ability to separate the two outflows varies between species. The leatherback has a powerful muscular ridge enabling almost complete separation of the outflows, supporting its actively swimming lifestyle. The ridge is less well developed in freshwater turtles like the sliders ( Trachemys ). Turtles are capable of enduring periods of anaerobic respiration longer than many other vertebrates. This process breaks down sugars incompletely to lactic acid , rather than all
8848-447: The lungs, as in other amniotes, so they have had to evolve special adaptations for respiration. The lungs of turtles are attached directly to the carapace above while below, connective tissue attaches them to the organs. They have multiple lateral (side) and medial (middle) chambers (the numbers of which vary between species) and one terminal (end) chamber. The lungs are ventilated using specific groups of abdominal muscles attached to
8960-458: The material of hair, horns, and claws. The carapace bones develop from ribs that grow sideways and develop into broad flat plates that join up to cover the body. Turtles are ectotherms or "cold-blooded", meaning that their internal temperature varies with their direct environment. They are generally opportunistic omnivores and mainly feed on plants and animals with limited movements. Many turtles migrate short distances seasonally. Sea turtles are
9072-854: The most likely result found by an analysis of turtle relationships using both fossil and genetic evidence by M.S. Lee, in 2013. This study found Eunotosaurus , usually regarded as a turtle relative, to be only very distantly related to turtles in the clade Parareptilia . † Araeoscelidia [REDACTED] † Claudiosaurus [REDACTED] † Younginiformes [REDACTED] Lepidosauromorpha [REDACTED] † Eosauropterygia [REDACTED] † Placodontia [REDACTED] † Sinosaurosphargis † Odontochelys † Proganochelys Testudines [REDACTED] † Choristodera [REDACTED] † Prolacertiformes [REDACTED] † Rhynchosauria [REDACTED] † Trilophosaurus [REDACTED] Archosauriformes [REDACTED] The cladogram below follows
9184-756: The most likely result found by another analysis of turtle relationships, this one using only fossil evidence, published by Rainer Schoch and Hans-Dieter Sues in 2015. This study found Eunotosaurus to be an actual early stem-turtle, though other versions of the analysis found weak support for it as a parareptile. † Kuehneosauridae [REDACTED] Rhynchocephalia [REDACTED] Squamata [REDACTED] † Eosauropterygia [REDACTED] † Placodontia [REDACTED] † Sinosaurosphargis † Eunotosaurus † Pappochelys [REDACTED] † Odontochelys † Proganochelys Testudines [REDACTED] Archosauromorpha [REDACTED] [REDACTED] The cladogram below follows
9296-508: The most powerful bites. For example, the durophagous Mesoclemmys nasuta has a bite force of 432 lbf (1,920 N). Species that are insectivorous , piscivorous (fish-eating), or omnivorous have lower bite forces. Living turtles lack teeth but have beaks made of keratin sheaths along the edges of the jaws. These sheaths may have sharp edges for cutting meat, serrations for clipping plants, or broad plates for breaking mollusks . Sea turtles, and several extinct forms, have evolved
9408-424: The mouth. The escalation includes 21–25 (usually 23) rows of dorsal scales at midbody, 138–157 ventral scales in both sexes, and 38–62 and 37–57 subcaudal scales in males and females, respectively. The subcaudals are usually single, but the percentage thereof decreases clinally from the northeast, where about 80% are undivided, to the southwest of the geographic range where as little as 50% may be undivided. On
9520-401: The nasal cavity, the latter of which are used to detect chemical signals. Experiments on green sea turtles showed they could learn to respond to a selection of different odorant chemicals such as triethylamine and cinnamaldehyde , which were detected by olfaction in the nose. Such signals could be used in navigation. The rigid shell of turtles is not capable of expanding and making room for
9632-422: The natal beach. There is experimental evidence that turtles have an effective magnetic sense, and that they use this in navigation . Proof that homing occurs is derived from genetic analysis of populations of loggerheads, hawksbills, leatherbacks, and olive ridleys by nesting place. For each of these species, the populations in different places have their own mitochondrial DNA genetic signatures that persist over
9744-448: The neck of the urinary bladder and above the pubis . Arid-living tortoises have bladders that serve as reserves of water, storing up to 20% of their body weight in fluids. The fluids are normally low in solutes , but higher during droughts when the reptile gains potassium salts from its plant diet. The bladder stores these salts until the tortoise finds fresh drinking water. To regulate the amount of salt in their bodies, sea turtles and
9856-410: The only reptiles that migrate long distances to lay their eggs on a favored beach. Turtles have appeared in myths and folktales around the world. Some terrestrial and freshwater species are widely kept as pets. Turtles have been hunted for their meat, for use in traditional medicine, and for their shells. Sea turtles are often killed accidentally as bycatch in fishing nets. Turtle habitats around
9968-476: The only reptiles that migrate long distances, more specifically the marine species that can travel up to thousands of kilometers. Some non-marine turtles, such as the species of Geochelone (terrestrial), Chelydra (freshwater), and Malaclemys (estuarine), migrate seasonally over much shorter distances, up to around 27 km (17 mi), to lay eggs. Such short migrations are comparable to those of some lizards, snakes, and crocodilians. Sea turtles nest in
10080-406: The organs that pull and push on them. Specifically, it is the turtle's large liver that compresses the lungs. Underneath the lungs, in the coelomic cavity , the liver is connected to the right lung by the root , and the stomach is directly attached to the left lung, and to the liver by a mesentery . When the liver is pulled down, inhalation begins. Supporting the lungs is a wall or septum , which
10192-426: The previous scutes every year, allowing researchers to estimate how long they have lived. They also age slowly . The survival rate for adult turtles can reach 99% per year. Zoologists have sought to explain the evolutionary origin of the turtles, and in particular of their unique shells. In 1914, Jan Versluys proposed that bony plates in the dermis, called osteoderms , fused to the ribs beneath them, later called
10304-423: The resulting low oxygen levels. They can moderate the increase in acidity during anaerobic (non-oxygen-based) respiration by chemical buffering and they can lie dormant for months, in aestivation or brumation . The heart has two atria but only one ventricle . The ventricle is subdivided into three chambers. A muscular ridge enables a complex pattern of blood flow so that the blood can be directed either to
10416-444: The returned oxygenated blood through the body's tissues. The cardiopulmonary system has both structural and physiological adaptations that distinguish it from other vertebrates. Turtles have a large lung volume and can move blood through non-pulmonary blood vessels, including some within the heart, to avoid the lungs while they are not breathing. They can hold their breath for much longer periods than other reptiles and they can tolerate
10528-405: The shell using an egg tooth , a sharp projection that exists temporarily on their upper beak. Hatchlings dig themselves out of the nest and find safety in vegetation or water. Some species stay in the nest for longer, be it for overwintering or to wait for the rain to loosen the soil for them to dig out. Young turtles are highly vulnerable to predators, both in the egg and as hatchlings. Mortality
10640-414: The southern copperhead has been found to hold the protein contortrostatin that halts the growth of cancer cells in mice and also stops the migration of the tumors to other sites. However, this is an animal model , and further testing is required to verify safety and efficacy in humans. The antivenom CroFab is used to treat copperhead envenomations that demonstrate localized or systemic reactions to
10752-413: The species, immersion periods vary between a minute and an hour. Some species can respire through the cloaca , which contains large sacs that are lined with many finger-like projections that take up dissolved oxygen from the water. Turtles share the linked circulatory and pulmonary (lung) systems of vertebrates, where the three-chambered heart pumps deoxygenated blood through the lungs and then pumps
10864-830: The species, the number of eggs laid varies from one to over 100. Larger females can lay eggs that are greater in number or bigger in size. Compared to freshwater turtles, tortoises deposit fewer but larger eggs. Females can lay multiple clutches throughout a season, particularly in species that experience unpredictable monsoons . Most mother turtles do no more in the way of parental care than covering their eggs and immediately leaving, though some species guard their nests for days or weeks. Eggs vary between rounded, oval, elongated, and between hard- and soft-shelled. Most species have their sex determined by temperature . In some species, higher temperatures produce females and lower ones produce males, while in others, milder temperatures produce males and both hot and cold extremes produce females. There
10976-424: The substrate. Freshwater turtles have more flexible legs and longer toes with webbing , giving them thrust in the water. Some of these species, such as snapping turtles and mud turtles , mainly walk along the water bottom, as they would on land. Others, such as terrapins, swim by paddling with all four limbs, switching between the opposing front and hind limbs, which keeps their direction stable. Sea turtles and
11088-405: The time they are in the egg to when they are adults. These vocalizations may serve to create group cohesion when migrating . The oblong turtle has a particularly large vocal range; producing sounds described as clacks, clicks, squawks, hoots, various kinds of chirps, wails, hooos , grunts, growls, blow bursts, howls, and drum rolls. Play behavior has been documented in some turtle species. In
11200-509: The treated snake bites in the United States. Five subspecies have been recognized in the past, but recent genetic analysis had yielded new species information. Its generic name is derived from the Greek words ankistron "hook, fishhook" and odon , variant of odous "tooth". The trivial name , or specific epithet , comes from the Latin contortus (twisted, intricate, complex), which
11312-473: The upstroke and on the downstroke. This is in contrast to similar-sized freshwater turtles (measurements having been made on young animals in each case) such as the Caspian turtle , which uses the front limbs like the oars of a rowing boat, creating substantial negative thrust on the recovery stroke in each cycle. In addition, the streamlining of the marine turtles reduces drag. As a result, marine turtles produce
11424-499: The use of antivenom. Bite symptoms include extreme pain, tingling, throbbing, swelling, and severe nausea. Damage can occur to muscle and bone tissue, especially when the bite occurs in the outer extremities such as the hands and feet, areas in which a large muscle mass is not available to absorb the venom. A bite from any venomous snake should be taken very seriously and immediate medical attention sought, as an allergic reaction and secondary infection are always possible. The venom of
11536-483: The venom. As many copperhead bites can be dry (no envenomation), CroFab is not given in the absence of a reaction (such as swelling) due to the risk of complications of an allergic reaction to the treatment. The antivenom can cause an immune reaction called serum sickness . Pain management , tetanus immunization, laboratory evaluation, and medical supervision in the case of complications are additional courses of action. In 2002, an Illinois poison control center report on
11648-449: The water and basking in the sun, while small terrestrial turtles move between sunny and shady places to adjust their temperature. Large species, both terrestrial and marine, have sufficient mass to give them substantial thermal inertia , meaning that they heat up or cool down over many hours. The Aldabra giant tortoise weighs up to some 60 kilograms (130 lb) and is able to allow its temperature to rise to some 33 °C (91 °F) on
11760-404: The water. Sea turtles in particular have streamlined shells that reduce drag and increase stability in the open ocean. Some turtle species have pointy or spiked shells that provide extra protection from predators and camouflage against the leafy ground. The lumps of a tortoise shell can tilt its body when it gets flipped over, allowing it to flip back. In male tortoises, the tip of the plastron
11872-403: The way to carbon dioxide and water as in aerobic (oxygen-based) respiration . They make use of the shell as a source of additional buffering agents for combating increased acidity, and as a sink for lactic acid. In sea turtles, the bladder is one unit and in most freshwater turtles, it is double-lobed. Sea turtle bladders are connected to two small accessory bladders, located at the sides to
11984-542: The winter, it hibernates in dens or limestone crevices, often together with timber rattlesnakes and black rat snakes . In the states around the Gulf of Mexico , however, this species is also found in coniferous forest . In the Chihuahuan Desert of West Texas and northern Mexico, it occurs in riparian habitats , usually near permanent or semipermanent water and sometimes in dry arroyos (brooks). This species
12096-688: The world are being destroyed. As a result of these pressures, many species are extinct or threatened with extinction. The word turtle is borrowed from the French word tortue or tortre 'turtle, tortoise '. It is a common name and may be used without knowledge of taxonomic distinctions. In North America, it may denote the order as a whole. In Britain, the name is used for sea turtles as opposed to freshwater terrapins and land-dwelling tortoises. In Australia, which lacks true tortoises (family Testudinidae), non-marine turtles were traditionally called tortoises, but more recently turtle has been used for
12208-582: The year but switching to water lilies during the summer. Some species have developed specialized diets such as the hawksbill, which eats sponges , the leatherback, which feeds on jellyfish , and the Mekong snail-eating turtle . While popularly thought of as mute, turtles make various sounds to communicate. One study which recorded 53 species found that all of them vocalized. Tortoises may bellow when courting and mating. Various species of both freshwater and sea turtles emit short, low-frequency calls from
12320-752: The years. This shows that the populations are distinct and that homing must be occurring reliably. Turtles have a wide variety of mating behaviors but do not form pair-bonds or social groups. In green sea turtles, females generally outnumber males. In terrestrial species, males are often larger than females and fighting between males establishes a dominance hierarchy for access to mates. For most semi-aquatic and bottom-walking aquatic species, combat occurs less often. Males of these species instead may use their size advantage to mate forcibly . In fully aquatic species, males are often smaller than females and rely on courtship displays to gain mating access to females. Courtship varies between species, and with habitat. It
12432-415: Was Archelon ischyros , a Late Cretaceous sea turtle up to 4.5 m (15 ft) long, 5.25 m (17 ft) wide between the tips of the front flippers, and estimated to have weighed over 2,200 kg (4,900 lb). The smallest living turtle is Chersobius signatus of South Africa, measuring no more than 10 cm (3.9 in) in length and weighing 172 g (6.1 oz). The shell of
12544-434: Was "four feet, six inches" (137.2 cm), but this may have been an approximation. The maximum length for A. c. contortrix is 132.1 cm (52 in) (Conant, 1958). The body is relatively stout and the head is broad and distinct from the neck. Because the snout slopes down and back, it appears less blunt than that of the cottonmouth, A. piscivorus . Consequently, the top of the head extends further forward than
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