Terrestrial locomotion has evolved as animals adapted from aquatic to terrestrial environments. Locomotion on land raises different problems than that in water, with reduced friction being replaced by the effects of gravity. There are three basic forms of locomotion found among terrestrial animals Legged – Moving by using appendages Limbless locomotion – moving without legs using the body itself as a propulsive structure. Rolling – rotating the body over the substrate Movement on appendages is the most common form of terrestrial locomotion, it is the basic form of locomotion of two major groups with many terrestrial members, the vertebrates and the arthropods. Important aspects of legged locomotion are posture, the number of legs, the functional structure of the leg and foot. There are many gaits, ways of moving the legs to locomote, such as walking, running, or jumping. Appendages can be used for movement in a lot of ways: the posture, the way the body is supported by the legs, is an important aspect.
There are three main ways in which vertebrates support themselves with their legs – sprawling, semi-erect, erect. Some animals may use different postures in different circumstances, depending on the posture's mechanical advantages. There is no detectable difference in energetic cost between stances; the "sprawling" posture is the most primitive, is the original limb posture from which the others evolved. The upper limbs are held horizontally, while the lower limbs are vertical, though upper limb angle may be increased in large animals; the body may drag along the ground, as in salamanders, or may be elevated, as in monitor lizards. This posture is associated with trotting gaits, the body flexes from side-to-side during movement to increase step length. All limbed reptiles and salamanders use this posture, as does the platypus and several species of frogs that walk. Unusual examples can be found among amphibious fish, such as the mudskipper, which drag themselves across land on their sturdy fins.
Among the invertebrates, most arthropods – which includes the most diverse group of animals, the insects – have a stance best described as sprawling. There is anecdotal evidence that some octopus species can drag themselves across land a short distance by hauling their body along by their tentacles – there may be video evidence of this; the semi-erect posture is more interpreted as an elevated sprawling posture. This mode of locomotion is found in large lizards such as monitor lizards and tegus. Mammals and birds have a erect posture, though each evolved it independently. In these groups the legs are placed beneath the body; this is linked with the evolution of endothermy, as it avoids Carrier's constraint and thus allows prolonged periods of activity. The erect stance is not the "most-evolved" stance. For example, the mesozoic prehistoric crocodilian Erpetosuchus is believed to have had a erect stance and been terrestrial; the number of locomotory appendages varies much between animals, sometimes the same animal may use different numbers of its legs in different circumstances.
The best contender for unipedal movement is the springtail, which while hexapedal, hurls itself away from danger using its furcula, a tail-like forked rod that can be unfurled from the underside of its body. A number of species stand on two legs, that is, they are bipedal; the group, bipedal is the birds, which have either an alternating or a hopping gait. There are a number of bipedal mammals. Most of these move by hopping – including the macropods such as kangaroos and various jumping rodents. Only a few mammals such as humans and the ground pangolin show an alternating bipedal gait. Cockroaches and some lizards may run on their two hind legs. With the exception of the birds, terrestrial vertebrate groups with legs are quadrupedal – the mammals and the amphibians move on four legs. There are many quadrupedal gaits; the most diverse group of animals on earth, the insects, are included in a larger taxon known as hexapods, most of which are hexapedal and standing on six legs. Exceptions among the insects include praying mantises and water scorpions, which are quadrupeds with their front two legs modified for grasping, some butterflies such as the Lycaenidae which use only four legs, some kinds of insect larvae that may have no legs, or additional prolegs.
Spiders and many of their relatives move on eight legs – they are octopedal. However, some creatures move on many more legs. Terrestrial crustaceans may have a fair number – woodlice having fourteen legs; as mentioned, some insect larvae such as caterpillars and sawfly larvae have up to five or nine additional fleshy prolegs in addition to the six legs normal for insects. Some species of invertebrate have more legs, the unusual velvet worm having stubby legs under the length of its body, with around several dozen pairs of legs. Centipedes have one pair of legs per body segment, with around 50 legs, but some species have over 200; the terrestrial animals with the most legs are the millipedes. They have two pairs of legs per body segment, with common species having between 80 and 400 legs overall – with the rare species Illacme plenipe
A hackamore is a type of animal headgear which does not have a bit. Instead, it has a special type of noseband that works on pressure points on the face and chin, it is most associated with certain styles of riding horses. Hackamores are most seen in western riding and other styles of riding derived from Spanish traditions, are seen in some English riding disciplines such as show jumping and the stadium phase of eventing. Various hackamore designs are popular for endurance riding. While used to start young horses, they are seen on mature horses with dental issues that make bit use painful, on horses with mouth or tongue injuries that would be aggravated by a bit; some riders like to use them in the winter to avoid putting a frozen metal bit into a horse's mouth. There are many styles, but the classic hackamore is a design featuring a bosal noseband, sometimes itself called a "bosal" or a "bosal hackamore", it has a long rope rein called a mecate and may add a type of stabilizing throatlatch called a fiador, held to the hackamore by a browband.
Other designs with heavy nosebands are called hackamores, though some bitless designs with lighter weight nosebands that work off tension rather than weight are called bitless bridles. A noseband with shanks and a curb chain to add leverage is called a mechanical hackamore, but is not considered a true hackamore. A simple leather noseband, or cavesson, is not a hackamore. Like a bit, a hackamore can be harsh, depending on the hands of the rider; the horse's face is soft and sensitive with many nerve endings. Misuse of a hackamore can not only cause pain and swelling on the nose and jaw, but improper fitting combined with rough use can cause damage to the cartilage on the horse's nose; the word "hackamore" is derived from the Spanish word jáquima, meaning headstall or halter, itself derived from Old Spanish xaquima. The Spanish had obtained the term from šakama. From the Americanized pronunciation of jaquima, the spelling "hackamore" entered the written English language by 1850, not long after the Mexican–American War.
The first hackamore was a piece of rope placed around the nose or head of a horse not long after domestication as early as 4,000 B. C. Early devices for controlling the horse may have been adapted from equipment used to control camels. Over time, more sophisticated means of using nose pressure were developed; the Persians beginning with the reign of Darius, c. 500 BC, were one of the first cultures known to have used a thick-plaited noseband to help the horse look and move in the same direction. This device, called a hakma added a third rein at the nose, was an innovation that allowed a rider to achieve collection by helping the horse flex at the poll joint; the third rein moved from the top of the noseband to under the chin, where it is still part of the modern mecate rein used on the bosal-style hackamore. The techniques of horse-training refined by the Persians influenced the works on horsemanship written by the Greek military commander Xenophon; this heavy noseband itself came to be known by many names, retaining the name hakma in Persio-Arabic tongues, but becoming the cavesson in French, the bosal in Spanish.
Another modern descendant is the modern longeing cavesson which includes a heavy noseband with a rein at the nose, but it is used for longeing, not for riding. The tradition of hackamore use in the United States came from the Spanish Californians, who were well respected for their horse-handling abilities. From this tradition, the American cowboy adopted the hackamore and two schools of use developed: The "buckaroo" or "California" tradition, most resembling that of the original vaqueros, the "Texas" tradition, which melded some Spanish technique with methods from the eastern states, creating a separate and unique style indigenous to the region. Today, it is the best known of the assorted "bitless bridling" systems of controlling the horse; the word "hackamore" has been defined many ways, both as a type of bitless bridle. However, both terms are descriptive; the traditional jaquima hackamore is made up of a headstall and mecate tied into looped reins and a lead rope. It is neither a halter nor a bridle without a bit.
"Anyone who makes the statement that a hackamore is just another type of halter... is admitting that he knows nothing about this fine piece of equipment." Today, hackamores can be made of leather, rope, cable or various plastics, sometimes in conjunction with metal parts. The main types are the classic bosal and the more modern sidepull, though other designs based on nose pressure loosely fall into this category. Other assorted designs of bitless headgear classed as "bitless bridles", are not true hackamores; these include the "cross-under" bitless bridle, which uses strap tension to control the horse, the mechanical "hackamore", which has leverage shanks. The bosal is the noseband element of the classic jaquima or true hackamore, is seen in western-style riding, it is derived from the Spanish tradition of the vaquero. It consists of a stiff rawhide noseband with reins attached to a large knot or "button" at the base from which the design derives its name; the reins are made from a specially tied length of rope called a mecate, tied in a specific manner to both adjust the size of the bosal, to make a looped rein with an extra length of rope that can be used as a lead rope.
In the Texas tradition, where the
The domestic dog is a member of the genus Canis, which forms part of the wolf-like canids, is the most abundant terrestrial carnivore. The dog and the extant gray wolf are sister taxa as modern wolves are not related to the wolves that were first domesticated, which implies that the direct ancestor of the dog is extinct; the dog was the first species to be domesticated and has been selectively bred over millennia for various behaviors, sensory capabilities, physical attributes. Their long association with humans has led dogs to be uniquely attuned to human behavior and they are able to thrive on a starch-rich diet that would be inadequate for other canid species. Dogs vary in shape and colors, they perform many roles for humans, such as hunting, pulling loads, assisting police and military, companionship and, more aiding disabled people and therapeutic roles. This influence on human society has given them the sobriquet of "man's best friend"; the term dog is applied both to the species as a whole, any adult male member of the same.
An adult female is a bitch. An adult male capable of reproduction is a stud. An adult female capable of reproduction is brood mother. Immature males or females are puppies. A group of pups from the same gestation period is called a litter; the father of a litter is a sire. It is possible for one litter to have multiple sires; the mother of a litter is a dam. A group of any three or more adults is a pack. In 1999, a study of mitochondrial DNA indicated that the domestic dog may have originated from multiple grey wolf populations, with the dingo and New Guinea singing dog "breeds" having developed at a time when human populations were more isolated from each other. In the third edition of Mammal Species of the World published in 2005, the mammalogist W. Christopher Wozencraft listed under the wolf Canis lupus its wild subspecies, proposed two additional subspecies: "familiaris Linneaus, 1758 " and "dingo Meyer, 1793 ". Wozencraft included hallstromi – the New Guinea singing dog – as a taxonomic synonym for the dingo.
Wozencraft referred to the mDNA study as one of the guides in forming his decision. The inclusion of familiaris and dingo under a "domestic dog" clade has been noted by other mammalogists; this classification by Wozencraft is debated among zoologists. The origin of the domestic dog includes the dog's evolutionary divergence from the wolf, its domestication, its development into dog types and dog breeds; the dog is a member of the genus Canis, which forms part of the wolf-like canids, was the first species and the only large carnivore to have been domesticated. The dog and the extant gray wolf are sister taxa, as modern wolves are not related to the population of wolves, first domesticated; the genetic divergence between dogs and wolves occurred between 40,000–20,000 years ago, just before or during the Last Glacial Maximum. This timespan represents the upper time-limit for the commencement of domestication because it is the time of divergence and not the time of domestication, which occurred later.
The domestication of animals commenced over 15,000 years ago, beginning with the grey wolf by nomadic hunter-gatherers. The archaeological record and genetic analysis show the remains of the Bonn–Oberkassel dog buried beside humans 14,200 years ago to be the first undisputed dog, with disputed remains occurring 36,000 years ago, it was not until 11,000 years ago that people living in the Near East entered into relationships with wild populations of aurochs, boar and goats. Where the domestication of the dog took place remains debated, with the most plausible proposals spanning Western Europe, Central Asia and East Asia; this has been made more complicated by the recent proposal that an initial wolf population split into East and West Eurasian groups. These two groups, before going extinct, were domesticated independently into two distinct dog populations between 14,000 and 6,400 years ago; the Western Eurasian dog population was and replaced by East Asian dogs introduced by humans at least 6,400 years ago.
This proposal is debated. Domestic dogs have been selectively bred for millennia for various behaviors, sensory capabilities, physical attributes. Modern dog breeds show more variation in size and behavior than any other domestic animal. Dogs are predators and scavengers, like many other predatory mammals, the dog has powerful muscles, fused wrist bones, a cardiovascular system that supports both sprinting and endurance, teeth for catching and tearing. Dogs are variable in height and weight; the smallest known adult dog was a Yorkshire Terrier, that stood only 6.3 cm at the shoulder, 9.5 cm in length along the head-and-body, weighed only 113 grams. The largest known dog was an English Mastiff which weighed 155.6 kg and was 250 cm from the snout to the tail. The tallest dog is a Great Dane; the dog's senses include vision, sense of smell, sense of taste and sensitivity to the earth's magnetic field. Another study suggested; the coats of domestic dogs are of two varieties: "double" being common with dogs originating from colder climates, made up of a coarse guard hair and a soft down hair, or "single", with the topcoat only.
Breeds may have stripe, or "star" of white fur on their chest or underside. Regarding coat appearance or h
Spade bit (horse)
The spade bit is a historic vaquero design for a type of curb bit with straight decorated shanks and a mouthpiece that includes a straight bar, a narrow port with a cricket, a "spoon," a flat rounded plate affixed above the port, supported by braces on either side. Considered a technical piece of equipment to be used only on a finished horse, the spade bit is a refined tool that experts compare to driving a sports car in its ability to convey precise commands to the horse. Not all horses have the conformation or temperament to become a finished spade bit horse, a process that takes a number of years and is complete until a horse has at least five years of training under saddle; the spade bit is an elaborate, complex bit that can only be properly used on a trained horse handled by a skilled rider. In the vaquero tradition, its use represents the highest level of trust and communication between horse and rider. Experts compare the handling of a horse trained in this manner to that of a Jaguar.
The process of training the spade bit horse takes five to seven years to complete. Its emphasis has always been on producing a finely tuned working horse and partner, emphasizing quality rather than on how the goal is reached; the conformation of the horse is a factor. Traditionally, the vaquero method starts a young horse using a hackamore, headgear with no bit that uses a heavy rawhide noseband, called a bosal, to control the horse; the horse moves to lighter bosals, next into a combination of headgear that represents a transitional period in its training. The rider carries two sets of reins, one set on the bosal and one on the curb, giving this gear its name, the "two-rein. After several years in a two-rein, the horse graduates into the spade bit. A light bosal called a bosalito remains on the horse by tradition without reins attached. Clayton, Lawrence. Vaqueros and buckaroos: The Genesis and Life of the Mounted North American Herders. Austin, TX: University of Texas Press. ISBN 978-0-292-71240-9.
"Buckaroos: Views of a Western Way of Life". Buckaroos in Paradise: Ranching Culture in Northern Nevada, 1945–1982. Library of Congress. 1980. Retrieved 2010-08-06. Varian, Sheila; the Vaquero Tradition: Hackamore, 2 Rein and Spade Bit. California: Santa Ynez Historical Society. Bennett, Deb Conquerors: The Roots of New World Horsemanship. Amigo Publications Inc. ISBN 0-9658533-0-6 Connell, Ed Hackamore Reinsman; the Longhorn Press, Texas. Fifth Printing, August, 1958. Jaheil, Jessica. "Bosal, spade - why?" Horse Sense, web page accessed July 11, 2011
A snaffle bit is the most common type of bit used while riding horses. It acts with direct pressure. A bridle utilizing only a snaffle bit is called a "snaffle bridle" in the English riding disciplines. A bridle that carries two bits, a curb bit and a snaffle, or "bradoon", is called a double bridle. A snaffle is not a bit with a jointed bit mouthpiece, as is thought. A bit is a snaffle, it is a bit without a shank. Therefore, a single- or double-jointed mouthpiece, though the most common designs for snaffle bits, does not make a bit a snaffle. A mullen mouth or a bar bit is a snaffle; the snaffle bit works on several parts of the horse's mouth. The rings serve to act on the side of the mouth, depending on design, the sides of the jawbone. A snaffle is sometimes mistakenly thought of as "any mild bit". While direct pressure without leverage is milder than pressure with leverage, certain types of snaffle bits can be harsh when manufactured with wire, twisted metal or other "sharp" elements. A thin or rough-surfaced snaffle, used harshly, can damage a horse's mouth.
Curb chains or straps have no effect on a true snaffle. English riders do not curb chain to a snaffle bit. While some riders in western disciplines do add a curb strap to the rings, it is a "hobble" for the rings, has no leverage effect and is there only as a safety feature to prevent the rings from being pulled through the mouth of the horse, should the animal gape open its mouth in an attempt to avoid the bit, an outcome prevented in an English bridle by the presence of a cavesson noseband; the snaffle differs from the pelham bit, the curb bit, the kimberwicke in that it is a non-leverage bit, so does not amplify the pressure applied by the reins. With a snaffle, one ounce of pressure applied by the reins to a snaffle mouthpiece will apply one ounce of pressure on the mouth. With a curb, one ounce of pressure on the reins will apply more – sometimes far more – than one ounce of pressure on the horse's mouth. There are many riders who do not know the true definition of a snaffle: a bit, non-leverage.
This results in a rider purchasing a jointed mouthpiece bit with shanks, because it is labeled a "snaffle," and believing that it is soft and kind because of the connotation the snaffle name has with being mild. In truth, the rider bought a curb bit with a jointed mouthpiece, a severe bit due to the combination of a nutcracker effect on the jaw and leverage from the shanks. A true snaffle does not curb bit. Although the kimberwicke appears to have a D-shaped bit ring like a snaffle, the bit mouthpiece is not centered on the ring, thus applying the reins creates leverage. Both are used with a curb chain, thus the ring acts like a bit shank and creates a slight amount of leverage, making it a type of curb bit. A true snaffle will not be able to slide up and down the rings of the bit or cheekpieces of the bridle, as this would place it in the gag bit category; the mouthpiece is the more important part of a snaffle. Thinner mouthpieces are more severe. Jointed mouthpiece: applies pressure to the tongue and bars with a "nutcracker" action.
This is the most common mouthpiece found on a snaffle. Mullen mouth: made of hard rubber or a half-moon of metal, it places pressure on the mouthpiece and bars, it is a mild mouthpiece. French mouth: a double-jointed mouthpiece with a bone-shaped link in the middle, it encourages the horse to relax. Mild. Dr. Bristol: a double-jointed mouthpiece with a thin rectangular link in the middle, set at an angle, creating a pressure point, it is a severe bit. The French link is similar but much gentler because the link in the middle is flat against the tongue and bar and has no pressure points. Neither the Dr. Bristol nor the French Link nutcracker, but their severity is opposite. Slow twist: a single-jointed mouthpiece with a slight twist in it. Stronger and more severe. Corkscrew: Many small edges amplifies the pressure on the mouth. Severe. Single- and double-twisted wire: two of the most severe mouthpieces, as they are not only thin, but they have a "nutcracker" action from the single joint and the mouthpiece concentrates pressure due to its severe twisting.
Roller mouthpieces: tend to make horses relax their mouth and activate the tongue, encouraging salivation and acceptance of the bit. This may focus tense or nervous horses to the bit. Hollow mouth: single-jointed with a thick, hollow mouthpiece which spreads out the pressure and makes the bit less severe. May not fit comfortably in some horses' mouths. There are several types of rings. Loose ring: slides through the mouthpiece. Tends to make the horse chew the bit. May pinch the corners of the horse's mouth if the holes in the mouthpiece are large, in which case a bit guard should be used. Egg butt/barrel head: mouthpiece does not rotate, is so more fixed in the horse's mouth, which some horses prefer. Will not pinch the lips. Dee-ring/ racing snaffle: ring in the shape of a "
The horse is one of two extant subspecies of Equus ferus. It is an odd-toed ungulate mammal belonging to the taxonomic family Equidae; the horse has evolved over the past 45 to 55 million years from a small multi-toed creature, into the large, single-toed animal of today. Humans began domesticating horses around 4000 BC, their domestication is believed to have been widespread by 3000 BC. Horses in the subspecies caballus are domesticated, although some domesticated populations live in the wild as feral horses; these feral populations are not true wild horses, as this term is used to describe horses that have never been domesticated, such as the endangered Przewalski's horse, a separate subspecies, the only remaining true wild horse. There is an extensive, specialized vocabulary used to describe equine-related concepts, covering everything from anatomy to life stages, colors, breeds and behavior. Horses' anatomy enables them to make use of speed to escape predators and they have a well-developed sense of balance and a strong fight-or-flight response.
Related to this need to flee from predators in the wild is an unusual trait: horses are able to sleep both standing up and lying down, with younger horses tending to sleep more than adults. Female horses, called mares, carry their young for 11 months, a young horse, called a foal, can stand and run shortly following birth. Most domesticated horses begin training in harness between the ages of two and four, they reach full adult development by age five, have an average lifespan of between 25 and 30 years. Horse breeds are loosely divided into three categories based on general temperament: spirited "hot bloods" with speed and endurance. There are more than 300 breeds of horse in the world today, developed for many different uses. Horses and humans interact in a wide variety of sport competitions and non-competitive recreational pursuits, as well as in working activities such as police work, agriculture and therapy. Horses were used in warfare, from which a wide variety of riding and driving techniques developed, using many different styles of equipment and methods of control.
Many products are derived from horses, including meat, hide, hair and pharmaceuticals extracted from the urine of pregnant mares. Humans provide domesticated horses with food and shelter, as well as attention from specialists such as veterinarians and farriers. Specific terms and specialized language are used to describe equine anatomy, different life stages and breeds. Depending on breed and environment, the modern domestic horse has a life expectancy of 25 to 30 years. Uncommonly, a few animals live into their 40s and beyond; the oldest verifiable record was "Old Billy", a 19th-century horse that lived to the age of 62. In modern times, Sugar Puff, listed in Guinness World Records as the world's oldest living pony, died in 2007 at age 56. Regardless of a horse or pony's actual birth date, for most competition purposes a year is added to its age each January 1 of each year in the Northern Hemisphere and each August 1 in the Southern Hemisphere; the exception is in endurance riding, where the minimum age to compete is based on the animal's actual calendar age.
The following terminology is used to describe horses of various ages: Foal: A foal of either sex less than one year old. A nursing foal is sometimes called a suckling and a foal, weaned is called a weanling. Most domesticated foals are weaned at five to seven months of age, although foals can be weaned at four months with no adverse physical effects. Yearling: A horse of either sex, between one and two years old. Colt: A male horse under the age of four. A common terminology error is to call any young horse a "colt", when the term only refers to young male horses. Filly: A female horse under the age of four. Mare: A female horse four years old and older. Stallion: A non-castrated male horse four years old and older; the term "horse" is sometimes used colloquially to refer to a stallion. Gelding: A castrated male horse of any age. In horse racing, these definitions may differ: For example, in the British Isles, Thoroughbred horse racing defines colts and fillies as less than five years old. However, Australian Thoroughbred racing defines fillies as less than four years old.
The height of horses is measured at the highest point of the withers. This point is used because it is a stable point of the anatomy, unlike the head or neck, which move up and down in relation to the body of the horse. In English-speaking countries, the height of horses is stated in units of hands and inches: one hand is equal to 4 inches; the height is expressed as the number of full hands, followed by a point the number of additional inches, ending with the abbreviation "h" or "hh". Thus, a horse described; the size of horses varies by breed, but is influenced by nutrition. Light riding horses range in height from 14 to 16 hands and can weigh from 380 to 550 kilograms. Larger riding horses start at about 15.2 hands and are as tall as 17 hands, weighing from 500 to 600 kilograms. Heavy or draft horses are at least 16 hands (64 inches, 16
A rope is a group of yarns, fibers or strands that are twisted or braided together into a larger and stronger form. Ropes so can be used for dragging and lifting. Rope is thicker and stronger than constructed cord and twine. Rope may be constructed of any long, fibrous material, but is constructed of certain natural or synthetic fibres. Synthetic fibre ropes are stronger than their natural fibre counterparts, they have a higher tensile strength, they are more resistant to rotting than ropes created from natural fibers, can be made to float on water, but synthetic rope possess certain disadvantages, including slipperiness, some can be damaged more by UV light. Common natural fibres for rope are manila hemp, linen, coir, jute and sisal. Synthetic fibres in use for rope-making include polypropylene, polyesters, polyethylene and acrylics; some ropes are constructed of mixtures of several fibres or use co-polymer fibres. Wire rope is made of steel or other metal alloys. Ropes have been constructed of other fibrous materials such as silk and hair, but such ropes are not available.
Rayon is a regenerated fibre used to make decorative rope. The twist of the strands in a twisted or braided rope serves not only to keep a rope together, but enables the rope to more evenly distribute tension among the individual strands. Without any twist in the rope, the shortest strand would always be supporting a much higher proportion of the total load; the long history of rope means. In systems that use the "inch", large ropes over 1 inch diameter such as are used on ships are measured by their circumference in inches. In metric systems of measurement, nominal diameter is given in millimetres; the current preferred international standard for rope sizes is to give the mass per unit length, in kilograms per metre. However sources otherwise using metric units may still give a "rope number" for large ropes, the circumference in inches. Rope is of paramount importance in fields as diverse as construction, exploration, sports and communications, has been used since prehistoric times. To fasten rope, many types of knots have been invented for countless uses.
Pulleys redirect the pulling force to another direction, can create mechanical advantage so that multiple strands of rope share a load and multiply the force applied to the end. Winches and capstans are machines designed to pull ropes; the modern sport of rock climbing uses so-called "dynamic" rope, which stretches under load in an elastic manner to absorb the energy required to arrest a person in free fall without generating forces high enough to injure them. Such ropes use a kernmantle construction, as described below. "Static" ropes, used for example in caving and rescue applications, are designed for minimal stretch. The UIAA, in concert with the CEN, oversees testing. Any rope bearing a GUIANA or CE certification tag is suitable for climbing. Despite the hundreds of thousands of falls climbers suffer every year, there are few recorded instances of a climbing rope breaking in a fall. Climbing ropes, however, do cut when under load. Keeping them away from sharp rock edges is imperative. Rock climbing ropes come with either a designation for double or twin use.
A single rope is the most common and it is intended to be used by itself, as a single strand. Single ropes range in thickness from 9 mm to 11 mm. Smaller ropes wear out faster. Double ropes are thinner ropes 9 mm and under, are intended for use as a pair; these ropes offer a greater margin or security against cutting, since it is unlikely that both ropes will be cut, but they complicate belaying and leading. Double ropes are reserved for ice and mixed climbing, where there is need for two ropes to rappel or abseil, they are popular among traditional climbers, in the UK, due to the ability to clip each rope into alternating pieces of protection. Twin ropes are not to be confused with doubles; when using twin ropes, both ropes are clipped into the same piece of protection, treating the two as a single strand. This would be favourable in a situation; however new lighter-weight ropes with greater safety have replaced this type of rope. The butterfly coil is a method of carrying a rope used by climbers where the rope remains attached to the climber and ready to be uncoiled at short notice.
Another method of carrying a rope is the alpine coil. Rope is an aerial acrobatics circus skill, where a performer makes artistic figures on a vertical suspended rope. Tricks performed on the rope are, for example, drops and hangs, they must be strong. See Corde lisse; the use of ropes for hunting, fastening, carrying and climbing dates back to prehistoric times. It is that the earliest "ropes" were occurring lengths of plant fibre, such as vines, followed soon by the first attempts at twisting and braiding these strands together to form the first proper ropes in the modern sense of the word. Impressions of cordage found on fired