Crane fly is a common name referring to any member of the insect family Tipulidae, of the order Diptera, true flies in the superfamily Tipuloidea. Cylindrotominae and Pediciinae have been ranked as subfamilies of Tipulidae by most authors, though elevated to family rank. In the most recent classifications, only Pediciidae is now ranked as a separate family, due to considerations of paraphyly. In colloquial speech, crane flies are sometimes known as mosquito hawks or daddy longlegs, a term used to describe opiliones or the family Pholcidae, both of which are arachnids; the larvae of crane flies are known as leatherjackets. Crane flies are found worldwide, though individual species have limited ranges, they are most diverse in the tropics, are common in northern latitudes and high elevations. The Tipulidae is one of the largest groups of flies, including over 15,000 species and subspecies in 525 genera and subgenera. Most crane flies were described by the entomologist Charles Paul Alexander, a fly specialist, in over 1000 research publications.
An adult crane fly, resembling an oversized mosquito has a slender body and stilt-like legs that are deciduous coming off the body. The wingspan is about 1.0 to 6.5 cm, though some species of Holorusia can reach 11 cm. The antennae have up to 19 segments, it is characterized by a V-shaped suture on the back of the thorax and by its wing venation. The rostrum is long. Tipulidae are large to medium-sized flies with elongated legs and abdomen, their colour is brown or grey. Ocelli are absent; the rostrum is short to short with a beak-like point called the nasus. The apical segment of the maxillary palpi is flagelliform and much longer than the subapical segment; the antennae have 13 segments. These are serrate, or ctenidial. There is a distinct V-shaped suture between the mesonotal scutum; the wings are longitudinally striped or marbled. In females the wings are sometimes rudimentary; the sub-costal vein joins through Sc2 with the radial vein, Sc1 is at most a short stump. There are four three branches of the radial vein merging into the alar margin.
The discoidal wing cell is present. The wing has two anal veins. Sternite 9 of the male genitalia has, with two pairs of appendages. Sometimes appendages are present on sternite 8; the female ovipositor has sclerotized valves and the cerci have a smooth or dentate lower margin. The valves are sometimes modified into short teeth; the larva is elongated cylindrical. The posterior two-thirds of the head capsule is enclosed or retracted within the prothoracic segment; the larva is metapneustic, but with vestigial lateral spiracles. The head capsule is sclerotized anteriorly and incised ventrally and dorsolaterally; the mandibles move in the horizontal or oblique plane. The abdominal segments have transverse creeping welts; the terminal segments of the abdomen are glabrous partially sclerotized and bearing posterior spiracles. The spiracular disc is surrounded by lobe-like projections and anal papillae or lobes; the adult female contains mature eggs as she emerges from her pupa, mates if a male is available.
Males search for females by walking or flying. Copulation may be accomplished in flight. Adults have a lifespan of 10 to 15 days; the female oviposits in wet soil or mats of algae. Some lay eggs on the surface of a water body or in dry soils, some simply drop them in flight. Most crane fly eggs are black in color, they have a filament, which may help anchor the egg in wet or aquatic environments. Crane fly larvae have been observed in many habitat types on dry land and in water, including marine and fresh water, they are cylindrical in shape, but taper toward the front end, the head capsule is retracted into the thorax. The abdomen may be lined with hairs, or studded with projections or welt-like spots. Projections may occur around the spiracles. Larvae may eat algae and living or decomposing plant matter, including wood; some are predatory. Larval habitats include all kinds of semiaquatic environments; some Tipulinae, including Dolichopeza Curtis, are found in moist to wet cushions of mosses or liverworts.
Ctenophora Meigen species are found in decaying sodden logs. Nephrotoma Meigen and Tipula Linnaeus larvae are found in dry soils of pasturelands and steppe. Tipulidae larvae are found in rich organic earth and mud, in wet spots in woods where the humus is saturated, in leaf litter or mud, decaying plant materials, or fruits in various stages of putrefaction. Larvae can be important in the soil ecosystem, because they process organic material and increase microbial activity. Larvae and adults are valuable prey items for many animals, including insects, fish, amphibians and mammals; the larvae of a few species consume other living aquatic insects and invertebrates, which could include mosquito larvae, though this has not been documented. Many adults, have such short lifespans that they do not eat at all, despite held beliefs that adult crane flies prey on mosquito populations, the adult crane fly is anatomically incapable of killing or consuming other insects; the common European crane fly, Tipula paludo
Reproduction is the biological process by which new individual organisms – "offspring" – are produced from their "parents". Reproduction is a fundamental feature of all known life. There are two forms of reproduction: sexual. In asexual reproduction, an organism can reproduce without the involvement of another organism. Asexual reproduction is not limited to single-celled organisms; the cloning of an organism is a form of asexual reproduction. By asexual reproduction, an organism creates a genetically identical copy of itself; the evolution of sexual reproduction is a major puzzle for biologists. The two-fold cost of sexual reproduction is that only 50% of organisms reproduce and organisms only pass on 50% of their genes. Sexual reproduction requires the sexual interaction of two specialized organisms, called gametes, which contain half the number of chromosomes of normal cells and are created by meiosis, with a male fertilizing a female of the same species to create a fertilized zygote; this produces offspring organisms whose genetic characteristics are derived from those of the two parental organisms.
Asexual reproduction is a process by which organisms create genetically similar or identical copies of themselves without the contribution of genetic material from another organism. Bacteria divide asexually via binary fission; these organisms do not possess different sexes, they are capable of "splitting" themselves into two or more copies of themselves. Most plants have the ability to reproduce asexually and the ant species Mycocepurus smithii is thought to reproduce by asexual means; some species that are capable of reproducing asexually, like hydra and jellyfish, may reproduce sexually. For instance, most plants are capable of vegetative reproduction—reproduction without seeds or spores—but can reproduce sexually. Bacteria may exchange genetic information by conjugation. Other ways of asexual reproduction include parthenogenesis and spore formation that involves only mitosis. Parthenogenesis is the development of embryo or seed without fertilization by a male. Parthenogenesis occurs in some species, including lower plants and vertebrates.
It is sometimes used to describe reproduction modes in hermaphroditic species which can self-fertilize. Sexual reproduction is a biological process that creates a new organism by combining the genetic material of two organisms in a process that starts with meiosis, a specialized type of cell division; each of two parent organisms contributes half of the offspring's genetic makeup by creating haploid gametes. Most organisms form two different types of gametes. In these anisogamous species, the two sexes are referred to as female. In isogamous species, the gametes are similar or identical in form, but may have separable properties and may be given other different names. For example, in the green alga, Chlamydomonas reinhardtii, there are so-called "plus" and "minus" gametes. A few types of organisms, such as many fungi and the ciliate Paramecium aurelia, have more than two "sexes", called syngens. Most animals and plants reproduce sexually. Sexually reproducing organisms have different sets of genes for every trait.
Offspring inherit one allele for each trait from each parent. Thus, offspring have a combination of the parents' genes, it is believed that "the masking of deleterious alleles favors the evolution of a dominant diploid phase in organisms that alternate between haploid and diploid phases" where recombination occurs freely. Bryophytes reproduce sexually, but the larger and commonly-seen organisms are haploid and produce gametes; the gametes fuse to form a zygote which develops into a sporangium, which in turn produces haploid spores. The diploid stage is small and short-lived compared to the haploid stage, i.e. haploid dominance. The advantage of diploidy, only exists in the diploid life generation. Bryophytes retain sexual reproduction despite the fact that the haploid stage does not benefit from heterosis; this may be an indication that the sexual reproduction has advantages other than heterosis, such as genetic recombination between members of the species, allowing the expression of a wider range of traits and thus making the population more able to survive environmental variation.
Allogamy is the fertilization of the combination of gametes from two parents the ovum from one individual with the spermatozoa of another. Self-fertilization known as autogamy, occurs in hermaphroditic organisms where the two gametes fused in fertilization come from the same individual, e.g. many vascular plants, some foraminiferans, some ciliates. The term "autogamy" is sometimes substituted for autogamous pollination and describes self-pollination within the same flower, distinguished from geitonogamous pollination, transfer of pollen to a different flower on the same flowering plant, or within a single monoecious Gymnosperm plant. Mitosis and meiosis are types of cell division. Mitosis occurs in somatic cells. Mitosis The resultant number of cells in mitosis is t
Domestic sheep are quadrupedal, ruminant mammals kept as livestock. Like most ruminants, sheep are members of the even-toed ungulates. Although the name sheep applies to many species in the genus Ovis, in everyday usage it always refers to Ovis aries. Numbering a little over one billion, domestic sheep are the most numerous species of sheep. An adult female sheep is referred to as a ewe, an intact male as a ram or a tup, a castrated male as a wether, a younger sheep as a lamb. Sheep are most descended from the wild mouflon of Europe and Asia. One of the earliest animals to be domesticated for agricultural purposes, sheep are raised for fleeces and milk. A sheep's wool is the most used animal fiber, is harvested by shearing. Ovine meat is called lamb when from younger animals and mutton when from older ones in Commonwealth countries, lamb in the United States. Sheep continue to be important for wool and meat today, are occasionally raised for pelts, as dairy animals, or as model organisms for science.
Sheep husbandry is practised throughout the majority of the inhabited world, has been fundamental to many civilizations. In the modern era, New Zealand, the southern and central South American nations, the British Isles are most associated with sheep production. Sheepraising has a large lexicon of unique terms which vary by region and dialect. Use of the word sheep began in Middle English as a derivation of the Old English word scēap. A group of sheep is called a herd or mob. Many other specific terms for the various life stages of sheep exist related to lambing and age. Being a key animal in the history of farming, sheep have a entrenched place in human culture, find representation in much modern language and symbology; as livestock, sheep are most associated with pastoral, Arcadian imagery. Sheep figure in many mythologies—such as the Golden Fleece—and major religions the Abrahamic traditions. In both ancient and modern religious ritual, sheep are used as sacrificial animals; the exact line of descent between domestic sheep and their wild ancestors is unclear.
The most common hypothesis states. Sheep were among the first animals to be domesticated by humankind. C in Mesopotamia; the rearing of sheep for secondary products, the resulting breed development, began in either southwest Asia or western Europe. Sheep were kept for meat and skins. Archaeological evidence from statuary found at sites in Iran suggests that selection for woolly sheep may have begun around 6000 BC, the earliest woven wool garments have been dated to two to three thousand years later. Sheep husbandry spread in Europe. Excavations show that in about 6000 BC, during the Neolithic period of prehistory, the Castelnovien people, living around Châteauneuf-les-Martigues near present-day Marseille in the south of France, were among the first in Europe to keep domestic sheep. From its inception, ancient Greek civilization relied on sheep as primary livestock, were said to name individual animals. Ancient Romans kept sheep on a wide scale, were an important agent in the spread of sheep raising.
Pliny the Elder, in his Natural History, speaks at length about wool. European colonists spread the practice to the New World from 1493 onwards. Domestic sheep are small ruminants with a crimped hair called wool and with horns forming a lateral spiral. Domestic sheep differ from their wild relatives and ancestors in several respects, having become uniquely neotenic as a result of selective breeding by humans. A few primitive breeds of sheep retain some of the characteristics of their wild cousins, such as short tails. Depending on breed, domestic sheep may have no horns at all, or horns in both sexes, or in males only. Most horned breeds have a single pair. Another trait unique to domestic sheep as compared to wild ovines is their wide variation in color. Wild sheep are variations of brown hues, variation within species is limited. Colors of domestic sheep range from pure white to dark chocolate brown, spotted or piebald. Selection for dyeable white fleeces began early in sheep domestication, as white wool is a dominant trait it spread quickly.
However, colored sheep do appear in many modern breeds, may appear as a recessive trait in white flocks. While white wool is desirable for large commercial markets, there is a niche market for colored fleeces for handspinning; the nature of the fleece varies among the breeds, from dense and crimped, to long and hairlike. There is variation of wool type and quality among members of the same flock, so wool classing is a step in the commercial processing of the fibre. Depending on breed, sheep show a range of weights, their rate of growth and mature weight is a heritable trait, selected for in breeding. Ewes weigh between 45 and 100 kilograms, rams between 45 and 160 kilograms; when all deciduous teeth have erupted, the sheep has 20 teeth. Mature sheep have 32 teeth; as with other ruminants, the front teeth in the lower jaw bite against a hard, toothless pad in the upper jaw. These are used to pick off vegetation the rear
Caterpillars are the larval stage of members of the order Lepidoptera. As with most common names, the application of the word is arbitrary and the larvae of sawflies are called caterpillars as well. Both lepidopteran and symphytan larvae have eruciform body shapes. Caterpillars of most species are herbivorous, but not all; some feed on other animal products. Caterpillars are voracious feeders and many of them are among the most serious of agricultural pests. In fact many moth species are best known in their caterpillar stages because of the damage they cause to fruits and other agricultural produce, whereas the moths are obscure and do no direct harm. Conversely, various species of caterpillar are valued as sources of silk, as human or animal food, or for biological control of pest plants; the origins of the word "caterpillar" date from the early 16th century. They derive from Middle English catirpel, catirpeller an alteration of Old North French catepelose: cate, cat + pelose, hairy; the inchworm, or looper caterpillars from the family Geometridae are so named because of the way they move, appearing to measure the earth.
Caterpillars have soft bodies that can grow between moults. Their size varies between instars from as small as 1 mm up to 14 cm; some larvae of the order Hymenoptera can appear like the caterpillars of the Lepidoptera. Such larvae are seen in the sawfly suborder; however while these larvae superficially resemble caterpillars, they can be distinguished by the presence of prolegs on every abdominal segment, an absence of crochets or hooks on the prolegs, one pair of prominent ocelli on the head capsule, an absence of the upside-down Y-shaped suture on the front of the head. Lepidopteran caterpillars can be differentiated from sawfly larvae by: the numbers of pairs of pro-legs; the number of stemmata. The presence of crochets on the prolegs. Sawfly larvae have an invariably smooth head capsule with no cleavage lines, while lepidopterous caterpillars bear an inverted "Y" or "V". Many animals feed on caterpillars; as a result, caterpillars have evolved various means of defense. Caterpillars have evolved defenses against physical conditions such as cold, hot or dry environmental conditions.
Some Arctic species like Gynaephora groenlandica have special basking and aggregation behaviours apart from physiological adaptations to remain in a dormant state. The appearance of a caterpillar can repel a predator: its markings and certain body parts can make it seem poisonous, or bigger in size and thus threatening, or non-edible; some types of caterpillars are indeed poisonous or distasteful and their bright coloring is aposematic. Others may mimic other animals while not being dangerous themselves. Many caterpillars are cryptically resemble the plants on which they feed. An example of caterpillars that use camouflage for defence is the species Nemoria arizonaria. If the caterpillars hatch in the spring and feed on oak catkins they appear green. If they hatch in the summer they appear dark colored, like oak twigs; the differential development is linked to the tannin content in the diet. Caterpillars may have spines or growths that resemble plant parts such as thorns; some look like objects in the environment such as bird droppings.
More aggressive self-defense measures are taken by some caterpillars. These measures include having spiny bristles or long fine hair-like setae with detachable tips that will irritate by lodging in the skin or mucous membranes; however some birds will swallow the hairiest of caterpillars. Other caterpillars acquire toxins from their host plants that render them unpalatable to most of their predators. For instance, ornate moth caterpillars utilize pyrrolizidine alkaloids that they obtain from their food plants to deter predators; the most aggressive caterpillar defenses are bristles associated with venom glands. These bristles are called urticating hairs. A venom, among the most potent defensive chemicals in any animal is produced by the South American silk moth genus Lonomia, its venom is an anticoagulant powerful enough to cause a human to hemorrhage to death. This chemical is being investigated for potential medical applications. Most urticating hairs range in effect from mild irritation to dermatitis.
Example: Brown-tail moth. Plants contain toxins which protect them from herbivores, but some caterpillars have evolved countermeasures which enable them to eat the leaves of such toxic plants. In addition to being unaffected by the poison, the caterpillars sequester it in their body, making them toxic to predators; the chemicals are carried on into the adult stages. These toxic species, such as the cinnabar moth and monarch caterpillars advertise themselves with the danger colors of red and black in bright stripes. Any predator that attempts to eat a caterpillar with an aggressive defense mechanism will learn and avoid future attempts; some caterpill
A fisherman or fisher is someone who captures fish and other animals from a body of water, or gathers shellfish. Worldwide, there are fish farmers. Fishermen may be both men or women. Fishing has existed as a means of obtaining food since the Mesolithic period. Fishing has existed as a means of obtaining food since the Mesolithic period. Fishing had become a major means of survival as well as a business venture. Fishing and the fisherman have influenced Ancient Egyptian religion. Bastet was manifested in the form of a catfish. In ancient Egyptian literature, the process that Amun used to create the world is associated with the tilapia's method of mouth-brooding. According to the FAO, there were about 39 million fishers in countries producing more than 200,000 tonnes in 2012, nearly 140% the number in 1995; the total fishery production of 66 million tonnes equated to an average productivity of 3.5 tonnes per person. Most of this growth took place in Asian countries, where four-fifths of world fishers and fish farmers dwell.
Most fishermen are men involved in deep-sea fisheries. Women fish in some regions collect shellfish and seaweed. In many artisanal fishing communities, women are responsible for making and repairing nets, post-harvest processing and marketing. Recreational fishing is fishing for competition, it can be contrasted with commercial fishing, fishing for economic profit, or subsistence fishing, fishing for survival. The most common form of recreational fishing is done with a rod, line and any one of a wide range of baits. Lures are used in place of bait; some people make handmade lures, including artificial flies. The practice of catching or attempting to catch fish with a hook is called angling; when angling, it is sometimes required that the fish be caught and released. Big-game fishing is fishing from boats to catch large open-water species such as tuna and marlin. Noodling and trout tickling are recreational activities. For some communities, fishing provides not only a source of food and work but community and cultural identity.
The fishing industry is hazardous for fishermen. Between 1992 and 1999, US commercial fishing vessels averaged 78 deaths per year; the main contributors to fatalities are: inadequate preparation for emergencies poor vessel maintenance and inadequate safety equipment lack of awareness of or ignoring stability issues. Many fishermen, while accepting that fishing is dangerous, staunchly defend their independence. Many proposed laws and additional regulation to increase safety have been defeated because fishermen oppose them. Alaska's commercial fishermen work in one of the world's harshest environments. Many of the hardships they endure include isolated fishing grounds, high winds, seasonal darkness cold water and short fishing seasons, where long work days are the norm. Fatigue, physical stress, financial pressures face most Alaska fishermen through their careers; the hazardous work conditions faced by fishermen have a strong impact on their safety. Out of 948 work-related deaths that took place in Alaska during 1990-2006, one-third occurred to fishermen.
This is equivalent to an estimated annual fatality rate of 128/100,000 workers/year. This fatality rate is 26 times that of the overall U. S. work-related fatality rate of 5/100,000 workers/year for the same time period. While the work-related fatality rate for commercial fishermen in Alaska is still high, it does appear to be decreasing: since 1990, there has been a 51 percent decline in the annual fatality rate; the successes in commercial fishing are due in part to the U. S. Coast Guard implementing new safety requirements in the early 1990s; these safety requirements contributed to 96 percent of the commercial fishermen surviving vessel sinkings/capsizings in 2004, whereas in 1991, only 73 percent survived. While the number of occupational deaths in commercial fishermen in Alaska has been reduced, there is a continuing pattern of losing 20 to 40 vessels every year. There are still about 100 fishermen. Successful rescue is still dependent on the expertly trained personnel of the US Coast Guard Search and Rescue operations, such efforts can be hindered by the harshness of seas and the weather.
Furthermore, the people involved in Search and Rescue operations are themselves at considerable risk for injury or death during these rescue attempts. Fishing Recreational fishing Aquaculture Fish farming Dirty and demeaning Fishery List of American fishers Fields, Leslie Leyland Out On The Deep Blue: Women and the Oceans They Fish. St. Martin's Press. ISBN 978-0-312-27726-0 Jones, Stephen Working Thin Waters: Conversations with Captain * Lawrence H. Malloy, Jr. University Press of New England. ISBN 978-1-58465-103-1 Moore, Charles W Did fishermen discover the New World? For Those in Peril: Dangers at Sea for fishermen on the East Coast of Scotland historyshelf.org Fisher Folk at Sea and Ashore North East Folklore Archive, Aberdeenshire Council. Retrieved 9 March 2011
Disinfectants are antimicrobial agents that are applied to the surface of non-living objects to destroy microorganisms that are living on the objects. Disinfection does not kill all microorganisms resistant bacterial spores. Disinfectants are different from other antimicrobial agents such as antibiotics, which destroy microorganisms within the body, antiseptics, which destroy microorganisms on living tissue. Disinfectants are different from biocides — the latter are intended to destroy all forms of life, not just microorganisms. Disinfectants work by interfering with their metabolism. Sanitizers are substances that clean and disinfect. Disinfectants kill more germs than sanitizers. Disinfectants are used in hospitals, dental surgeries and bathrooms to kill infectious organisms. Bacterial endospores are most resistant to disinfectants, but some viruses and bacteria possess some tolerance. In wastewater treatment, a disinfection step with chlorine, ultra-violet radiation or ozonation can be included as tertiary treatment to remove pathogens from wastewater, for example if it is to be reused to irrigate golf courses.
An alternative term used in the sanitation sector for disinfection of waste streams, sewage sludge or fecal sludge is sanitisation or sanitization. A perfect disinfectant would offer complete and full microbiological sterilisation, without harming humans and useful form of life, be inexpensive, noncorrosive. However, most disinfectants are by nature harmful to humans or animals. Most modern household disinfectants contain Bitrex, an exceptionally bitter substance added to discourage ingestion, as a safety measure; those that are used indoors should never be mixed with other cleaning products as chemical reactions can occur. The choice of disinfectant to be used depends on the particular situation; some disinfectants have a wide spectrum, while others kill a smaller range of disease-causing organisms but are preferred for other properties. There are arguments for creating or maintaining conditions that are not conducive to bacterial survival and multiplication, rather than attempting to kill them with chemicals.
Bacteria can increase in number quickly, which enables them to evolve rapidly. Should some bacteria survive a chemical attack, they give rise to new generations composed of bacteria that have resistance to the particular chemical used. Under a sustained chemical attack, the surviving bacteria in successive generations are resistant to the chemical used, the chemical is rendered ineffective. For this reason, some question the wisdom of impregnating cloths, cutting boards and worktops in the home with bactericidal chemicals. Air disinfectants are chemical substances capable of disinfecting microorganisms suspended in the air. Disinfectants are assumed to be limited to use on surfaces, but, not the case. In 1928, a study found. An air disinfectant must be dispersed either as an aerosol or vapour at a sufficient concentration in the air to cause the number of viable infectious microorganisms to be reduced. In the 1940s and early 1950s, further studies showed inactivation of diverse bacteria, influenza virus, Penicillium chrysogenum mold fungus using various glycols, principally propylene glycol and triethylene glycol.
In principle, these chemical substances are ideal air disinfectants because they have both high lethality to microorganisms and low mammalian toxicity. Although glycols are effective air disinfectants in controlled laboratory environments, it is more difficult to use them in real-world environments because the disinfection of air is sensitive to continuous action. Continuous action in real-world environments with outside air exchanges at door, HVAC, window interfaces, in the presence of materials that adsorb and remove glycols from the air, poses engineering challenges that are not critical for surface disinfection; the engineering challenge associated with creating a sufficient concentration of the glycol vapours in the air have not to date been sufficiently addressed. Alcohol and alcohol plus Quaternary ammonium cation based compounds comprise a class of proven surface sanitizers and disinfectants approved by the EPA and the Centers for Disease Control for use as a hospital grade disinfectant.
Alcohols are most effective when combined with distilled water to facilitate diffusion through the cell membrane. A mixture of 70% ethanol or isopropanol diluted in water is effective against a wide spectrum of bacteria, though higher concentrations are needed to disinfect wet surfaces. Additionally, high-concentration mixtures are required to inactivate lipid-enveloped viruses; the efficacy of alcohol is enhanced. The synergistic effect of 29.4% ethanol with dodecanoic acid is effective against a broad spectrum of bacteria and viruses. Further testing is being performed against Clostridium difficile spores with higher concentrations of ethanol and dodecanoic acid, which proved effective with a contact time of ten minutes. Aldehydes, such as formaldehyde and glutaraldehyde, have a wide microbiocidal activity and are sporicidal and fu
Porcupines are rodents with a coat of sharp spines, or quills, that protect against predators. The term covers two families of animals, the Old World porcupines of family Hystricidae, the New World porcupines of family Erethizontidae. Both families belong to the infraorder Hystricognathi within the profoundly diverse order Rodentia and display superficially similar coats of quills: despite this, the two groups are distinct from each other and are not related to each other within the Hystricognathi; the Old World porcupines live in southern Europe and most of Africa. They are large and nocturnal. In taxonomic terms, they form the family Hystricidae; the New World porcupines are indigenous to northern South America. They can climb trees, where some species spend their entire lives, they are less nocturnal than their Old World relatives, smaller. In taxonomic terms, they form the family Erethizontidae. Most porcupines are about 60–90 cm long, with an 20–25 cm long tail. Weighing 5–16 kg, they are rounded and slow, use aposematic strategy of defense.
Porcupines occur in various shades of brown and white. Porcupines' spiny protection resembles that of the unrelated erinaceomorph hedgehogs and Australian monotreme echidnas; the name "porcupine" comes from Latin porcus pig + spina spine, via Old Italian—Middle French—Middle English. A regional American name for the animal is quill pig. Fossils belonging to the genus Hystrix date back to the late Miocene of the continent of Africa. A porcupine is any of 58 species of rodents belonging to the families Hystricidae. Porcupines vary in size considerably: Rothschild's porcupine of South America weighs less than a kilogram; the two families of porcupines are quite different, although both belong to the Hystricognathi branch of the vast order Rodentia, they are not related. The 11 Old World porcupines tend to be large, have spikes grouped in clusters; the two subfamilies of New World porcupines are smaller, have their quills attached singly rather than grouped in clusters, are excellent climbers, spending much of their time in trees.
The New World porcupines evolved their spines independently and are more related to several other families of rodents than they are to the Old World porcupines. Porcupines have a high longevity and had held the record for being the longest-living rodent, with one individual living to 27 years, until the record was broken in 2002 by a naked mole-rat living to 28 years; the North American porcupine is an herbivore. In the winter, it may eat bark, it climbs trees to find food. The African porcupine is not a climber and forages on the ground, it is nocturnal, but will sometimes forage for food in the day, eating bark, roots and berries, as well as farm crops. Porcupines are eaten as a delicacy. Defensive behaviour displays in a porcupine depend on sight and sound. Displays are shown when a porcupine becomes agitated or annoyed. There are four main displays seen in a porcupine which are quill erection, teeth clattering, emitting of odour, attack; these displays are ranked from least aggressive to most aggressive respectively.
A porcupine's colouring aids in part of its defence as most of the predators are nocturnal and colour blind. A porcupine's markings are white; the dark body and coarse hair of the porcupine are a dark brown/black and when quills are raised, present a white strip down its back mimicking the look of a skunk. This, along with the raising of the sharp quills, deters predators. Along with the raising of the quills, porcupines clatter their teeth causing warning noise to let predators know not to come closer; the incisors vibrate against each other, the strike zone shifts back and the cheek teeth clatter. This behaviour is paired with body shivering, used to further display the dangerous quills; the rattling of quills is aided by the hollow quills at the back end of the porcupine. The use of odor is when the sound have failed. An invasive scent is produced from the skin above the tail in times of stress, is seen with quill erection. If the above processes fail, the porcupine will attack by running sideways or backwards into predators.
A porcupines tail is able to swing in the direction of the predator. If contact is made, the quills could be impaled into the predator causing death. Porcupines' quills, or spines, take on various forms, depending on the species, but all are modified hairs coated with thick plates of keratin, embedded in the skin musculature. Old World porcupines have quills embedded in clusters, whereas in New World porcupines, single quills are interspersed with bristles and hair. Quills may drop out when the porcupine shakes its body. New quills grow to replace lost ones. Porcupines were long believed to have the ability to project their quills to a considerable distance at an enemy, but this has since been proven to be untrue. There are some possible antibiotic properties within the quills associated with the free fatty acids coating the quills; the antibiotic properties are believed to aid a porcupine. Porcupines are only o