ratio of word probabilities predicted from brain for cow and ant

cow	ant
top 10 words in brain distribution (in article): animal species breed male cat human wild dog female food	top 10 words in brain distribution (in article): species animal plant human cell male breed food female form
top 10 words in brain distribution (not in article): wolf hunt bear lion elephant prey eat bird tree tiger	top 10 words in brain distribution (not in article): cat wolf wild dog lion elephant fish tiger bone deer
times more probable under cow 30 20 10 6 4 2.5 1.25 1 1.25 2.5 4 6 10 20 30 times more probable under ant (words not in the model)
Cattle'", colloquially referred to as "'cows'", are domesticated ungulates, a member of the subfamily Bovinae of the family Bovidae. They are raised as livestock for meat (called beef and veal), dairy products (milk), leather and as draft animals (pulling carts, plows and the like). In some countries, such as India, they are honored in religious ceremonies and revered. It is estimated that there are 1.3 billion cattle in the world today. Species of cattle. Cattle were originally identified by Carolus Linnaeus as three separate species. These were "Bos taurus", the European cattle, including similar types from Africa and Asia; "Bos indicus", the zebu; and the extinct "Bos primigenius", the aurochs. The aurochs is ancestral to both zebu and European cattle. More recently these three have increasingly been grouped as one species, with "Bos primigenius taurus", "Bos primigenius indicus" and "Bos primigenius primigenius" as the subspecies. Complicating the matter is the ability of cattle to interbreed with other closely related species. Hybrid individuals and even breeds exist, not only between European cattle and zebu but also with yaks (called a dzo), banteng, gaur, and bison ("cattalo"), a cross-genera hybrid. For example, genetic testing of the Dwarf Lulu breed, the only humpless "Bos taurus"-type" cattle in Nepal, found them to be a mix of European cattle, zebu and yak. Cattle cannot successfully be bred with water buffalo or African buffalo. The aurochs originally ranged throughout Europe, North Africa, and much of Asia. In historical times, their range was restricted to Europe, and the last animals were killed by poachers in Masovia, Poland, in 1627. Breeders have attempted to recreate cattle of similar appearance to aurochs by crossing of domesticated cattle breeds, creating the Heck cattle breed. (See also aurochs and zebu articles.) Word origin. "Cattle" did not originate as a name for bovine animals. It derives from the Latin "caput", head, and originally meant movable property, especially livestock of any kind. The word is closely related to "chattel" (a unit of personal property) and "capital" in the economic sense. Older English sources like King James Version of the Bible refer to livestock in general as cattle (as opposed to the word deer which then was used for wild animals). Additionally other species of the genus "Bos" are sometimes called wild cattle. Today, the modern meaning of "cattle", without any other qualifier, is usually restricted to domesticated bovines. Terminology of cattle. In general, the same words are used in different parts of the world but with minor differences in the definitions. The terminology described here contrasts the differences in definition between the United States and other British influenced parts of world such as Canada, Australia, New Zealand, Ireland, and the United Kingdom. Singular terminology dilemma. "Cattle" can only be used in the plural and not in the singular: it is a plurale tantum. Thus one may refer to "three cattle" or "some cattle", but not "one cattle". There is no universally used singular equivalent in modern English to "cattle", other than the gender and age-specific terms such as cow, bull, steer and heifer. Strictly speaking, the singular noun for the domestic bovine was "ox", however, "ox" today is rarely used in this general sense. An ox today generally denotes a draft beast, most commonly a castrated male (but is not to be confused with the unrelated wild musk ox). "Cow" has been in general use as a singular for the collective "cattle" in spite of the objections of those who say that it is a female-specific term, so that that phrases such as "that cow is a bull" would be absurd from a lexicographic standpoint. However, it is easy to use when a singular is needed and the gender is not known, as in "There is a cow in the road". Further, any herd of fully mature cattle in or near a pasture is statistically likely to consist mostly of cows, so the term is probably accurate even in the restrictive sense. Other than the few bulls needed for breeding, the vast majority of male cattle are castrated as calves and slaughtered for meat before the age of three years. Thus, in a pastured herd, any calves or herd bulls usually are clearly distinguishable from the cows due to distinctively different sizes and clear anatomical differences. The Oxford English Dictionary lists the use of "cows" as a synonym for "cattle" as an American usage. Merriam-Webster, a U.S. dictionary, recognizes the non-gender-specific use of "cow" as an alternate definition, whereas Collins, a UK dictionary, does not. Colloquially, more general non-specific terms may denote cattle when a singular form is needed. Australian, New Zealand and British farmers use the term "beast" or "cattle beast". "Bovine" is also used in Britain. The term "critter" is common in the western United States and Canada, particularly when referring to young cattle. In some areas of the American South (particularly the Appalachian region), where both dairy and beef cattle are present, an individual animal was once called a "beef critter", though that term is becoming archaic. Other terminology. Cattle raised for human consumption are called "beef cattle". Within the beef cattle industry in parts of the United States, the term "beef" (plural "beeves") is still used in its archaic sense to refer to an animal of either gender. Cows of certain breeds that are kept for the milk they give are called "dairy cows" or "milking cows" (formerly "milch cows" – "milch" was pronounced as "milk"). Most young male offspring of dairy cows are sold for veal, and may be referred to as "veal calves." The term "dogies" was once used to describe calves and young steers in the context of ranch work in the American west, as in "Keep them dogies moving," but in modern use is considered archaic unless used in a humorous context. In some places, a cow kept to provide milk for one family is called a "house cow". Other obsolete terms for cattle include "neat" (this use survives in "neatsfoot oil", extracted from the feet and legs of cattle), and "beefing" (young animal fit for slaughter). An onomatopoeic term for one of the commonest sounds made by cattle is "moo", and this sound is also called "lowing". There are a number of other sounds made by cattle, including calves "bawling", and bulls "bellowing" (a high-pitched yodeling call). The bullroarer makes a sound similar to a territorial call made by bulls. Anatomy. Cattle have one stomach with four compartments. They are the rumen, reticulum, omasum, and abomasum, the rumen being the largest compartment. Cattle sometimes consume metal objects which are deposited in the reticulum, the smallest compartment, and this is where hardware disease occurs. The reticulum is known as the "Honeycomb." The omasum's main function is to absorb water and nutrients from the digestible feed. The omasum is known as the "Many Plies." The abomasum is like the human stomach; this is why it is known as the "true stomach". Cattle are ruminants, meaning that they have a digestive system that allows use of otherwise indigestible foods by repeatedly regurgitating and rechewing them as "cud". The cud is then reswallowed and further digested by specialised microorganisms in the rumen. These microbes are primarily responsible for decomposing cellulose and other carbohydrates into volatile fatty acids that cattle use as their primary metabolic fuel. The microbes inside of the rumen are also able to synthesize amino acids from non-protein nitrogenous sources such as urea and ammonia. As these microbes reproduce in the rumen, older generations die and their carcasses continue on through the digestive tract. These carcasses are then partially digested by the cattle, allowing it to gain a high quality protein source. These features allow cattle to thrive on grasses and other vegetation. The gestation period for a cow is nine months. A newborn calf weighs. The world record for the heaviest bull was a Chianina named Donetto, when he was exhibited at the Arezzo show in 1955. The heaviest steer was eight year old ‘Old Ben’, a Shorthorn Hereford cross weighing in at in 1910. Steers are generally killed before reaching. Breeding stock usually live to about 15 years (occasionally as much as 25 years). A common misconception about cattle (particularly bulls) is that they are enraged by the color red (something provocative is often said to be "like a red flag to a bull"). This is incorrect, as cattle are red-green color-blind. The myth arose from the use of red capes in the sport of bullfighting; in fact, two different capes are used. The capote is a large, flowing cape that is magenta and yellow. The more famous muleta is the smaller, red cape, used exclusively for the final, fatal segment of the fight. It is not the color of the cape that angers the bull, but rather the movement of the fabric that irritates the bull and incites it to charge. Although cattle cannot distinguish red from green, they do have two kinds of color receptors in their retinas (cone cells) and so are theoretically able to distinguish some colors, probably in a similar way to other red-green color-blind or dichromatic mammals (such as dogs, cats, horses and up to ten percent of male humans). Domestication and husbandry. Cattle occupy a unique role in human history, domesticated since at least the early Neolithic. They are raised for meat (beef cattle), dairy products and hides. They are also used as draft animals and in certain sports. Some consider cattle the oldest form of wealth, and cattle raiding consequently one of the earliest forms of theft. Cattle are often raised by allowing herds to graze on the grasses of large tracts of rangeland. Raising cattle in this manner allows the use of land that might be unsuitable for growing crops. The most common interactions with cattle involve daily feeding, cleaning and milking. Many routine husbandry practices involve ear tagging, dehorning, loading, medical operations, vaccinations and hoof care, as well as training for agricultural shows and preparations. There are also some cultural differences in working with cattle- the cattle husbandry of Fulani men rests on behavioural techniques, whereas in Europe cattle are controlled primarily by physical means like fences. Breeders utilise cattle husbandry to reduce M. bovis infection susceptibility by selective breeding and maintaining herd health to avoid concurrent disease. Cattle are farmed for beef, veal, dairy, leather and they are less commonly used simply to maintain grassland for wildlife- for example, in Epping Forest, England. They are often used in some of the most wild places for livestock. Depending on the breed, cattle can survive on hill grazing, heaths, marshes, moors and semi desert. Modern cows are more commercial than older breeds and, having become more specialized, are less versatile. For this reason many smaller farmers still favor old breeds, like the dairy breed of cattle Jersey. In Portugal, Spain, Southern France and some Latin American countries, bulls are used in the activity of bullfighting; a similar activity, Jallikattu, is seen in South India; in many other countries this is illegal. Other activities such as bull riding are seen as part of a rodeo, especially in North America. Bull-leaping, a central ritual in Bronze Age Minoan culture (see Bull (mythology)), still exists in southwestern France. In modern times, cattle are also entered into agricultural competitions. These competitions can involve live cattle or cattle carcasses. In terms of food intake by humans, consumption of cattle is less efficient than of grain or vegetables with regard to land use, and hence cattle grazing consumes more area than such other agricultural production. Nonetheless, cattle and other forms of domesticated animals can sometimes help to utilize plant resources in areas not easily amenable to other forms of agriculture. These factors were not as important in earlier times prior to the Earth's large human population. Environmental impact. A 400-page United Nations report from the Food and Agriculture Organization (FAO) states that cattle farming is "responsible for 18% of greenhouse gases." The production of cattle to feed and clothe humans stresses ecosystems around the world, and is assessed to be one of the top three environmental problems in the world on a local to global scale. The report, entitled "Livestock's Long Shadow", also surveys the environmental damage from sheep, chickens, pigs and goats. But in almost every case, the world's 1.5 billion cattle are cited as the greatest adverse impact with respect to climate change as well as species extinction. The report concludes that, unless changes are made, the massive damage reckoned to be due to livestock may more than double by 2050, as demand for meat increases. One of the cited changes suggests that intensification of the livestock industry may be suggested, since intensification leads to less land for a given level of production. Some microbes respire in the cattle gut by an anaerobic process known as methanogenesis (producing the gas methane). Cattle emit a large volume of methane, 95% of it through eructation or burping, not flatulence. As the carbon in the methane comes from the digestion of vegetation produced by photosynthesis, its release into the air by this process would normally be considered harmless, because there is no net increase in carbon in the atmosphere — it's removed as carbon dioxide from the air by photosynthesis and returned to it as methane. Methane is a more potent greenhouse gas than carbon dioxide, having a warming effect 23 to 50 times greater, and according to Takahashi and Young "even a small increase in methane concentration in the atmosphere exerts a potentially significant contribution to global warming". Further analysis to the methane gas produced by livestock as a contributor to the increase in greenhouse gases is provided by Weart. Research is underway on methods of reducing this source of methane, by the use of dietary supplements, or treatments to reduce the proportion of methanogenetic microbes, perhaps by vaccination. Cattle are fed a concentrated high-corn diet which produces rapid weight gain, but this has side effects which include increased acidity in the digestive system. When improperly handled, manure and other byproducts of concentrated agriculture also have environmental consequences. Grazing by cattle at low intensities can create a favourable environment for native herbs and forbs; however, in most world regions cattle are reducing biodiversity due to overgrazing driven by food demands by an expanding human population. Oxen== Oxen'" (singular "'ox'") are large and heavyset breeds of "Bos taurus" cattle trained as draft animals. Often they are adult, castrated males. Usually an ox is over four years old due to the need for training and to allow it to grow to full size. Oxen are used for plowing, transport, hauling cargo, grain-grinding by trampling or by powering machines, irrigation by powering pumps, and wagon drawing. Oxen were commonly used to skid logs in forests, and sometimes still are, in low-impact select-cut logging. Oxen are most often used in teams of two, paired, for light work such as carting. In the past, teams might have been larger, with some teams exceeding twenty animals when used for logging. An ox is nothing more than a mature bovine with an "education." The education consists of the animal's learning to respond appropriately to the teamster's (ox driver's) signals. These signals are given by verbal commands or by noise (whip cracks) and many teamsters were known for their voices and language. In North America, the commands are (1) "get up", (2) "whoa", (3) "back up", (4) "gee" (turn right) and (5) "haw" (turn left). Oxen must be painstakingly trained from a young age. Their teamster must provide as many as a dozen yokes of different sizes as the animals grow. A wooden yoke is fastened about the neck of each pair so that the force of draft is distributed across their shoulders. From calves, oxen are chosen with horns since the horns hold the yoke in place when the oxen lower their heads, back up, or slow down (particularly with a wheeled vehicle going downhill). Yoked oxen cannot slow a load like harnessed horses can; the load has to be controlled downhill by other means. The gait of the ox is often important to ox trainers, since the speed the animal walks should roughly match the gait of the ox driver who must work with it. U.S. ox trainers favored larger breeds for their ability to do more work and for their intelligence. Because they are larger animals, the typical ox is the male of a breed, rather than the smaller female. Females are potentially more useful producing calves and milk. Oxen can pull harder and longer than horses, particularly on obstinate or almost un-movable loads. This is one of the reasons that teams drag logs from forests long after horses had taken over most other draft uses in Europe and North America. Though not as fast as horses, they are less prone to injury because they are more sure-footed and do not try to jerk the load. An "ox" is not a unique breed of bovine, nor have any "blue" oxen lived outside the folk tales surrounding Paul Bunyan, the mythical American logger. A possible exception and antecedent to this legend is the Belgian Blue breed which is known primarily for its unusual musculature and at times exhibits unusual white blue, blue roan, or blue coloration. The unusual musculature of the breed is believed to be due to a natural mutation of the gene that codes for the protein Myostatin, which is responsible for normal muscle atrophy. Many oxen are used worldwide, especially in developing countries. Ox is also used for various cattle products, irrespective of age, sex or training of the beast – for example, ox-blood, ox-liver, ox-kidney, ox-heart, ox-hide. Hindu tradition. Cows are venerated within the Hindu religion of India. According to Vedic scripture they are to be treated with the same respect 'as one's mother' because of the milk they provide; "The cow is my mother. The bull is my sire." They appear in numerous stories from the Puranas and Vedas, for example the deity Krishna is brought up in a family of cowherders, and given the name Govinda (protector of the cows). Also Shiva is traditionally said to ride on the back of a bull named Nandi. Bulls in particular are seen as a symbolic emblem of selfless duty and religion. In ancient rural India every household had a few cows which provided a constant supply of milk and a few bulls that helped as draft animals. Many Hindus feel that at least it was economically wise to keep cattle for their milk rather than consume their flesh for one single meal. Gandhi explains his feelings about cow protection as follows: "The cow to me means the entire sub-human world, extending man's sympathies beyond his own species. Man through the cow is enjoined to realize his identity with all that lives. Why the ancient rishis selected the cow for apotheosis is obvious to me. The cow in India was the best comparison; she was the giver of plenty. Not only did she give milk, but she also made agriculture possible. The cow is a poem of pity; one reads pity in the gentle animal. She is the second mother to millions of mankind. Protection of the cow means protection of the whole dumb creation of God. The appeal of the lower order of creation is all the more forceful because it is speechless." In heraldry. Cattle are typically represented in heraldry by the bull'". Present status. The world cattle population is estimated to be about 995,838,000 head. India is the nation with the largest number of cattle, about 281,700,000 or 28.29% of the world cattle population, followed by Brazil: 187,087,000, 18.79%; China: 139,721,000, 14.03%; the United States: 96,669,000, 9.71%; EU-27: at 87,650,000, 8.80%; Argentina: 51,062,000, 5.13%; Australia: 29,202,000, 2.93%; South Africa: 14,187,000, 1.42%; Canada: 13,945,000, 1.40% and other countries: 49,756,000 5.00%. Africa has about 20,000,000 head of cattle, many of which are raised in traditional ways and serve partly as tokens of their owner's wealth. Cattle today are the basis of a multi-billion dollar industry worldwide. The international trade in beef for 2000 was over $30 billion and represented only 23 percent of world beef production. (Clay 2004). The production of milk, which is also made into cheese, butter, yogurt, and other dairy products, is comparable in economic size to beef production and provides an important part of the food supply for many of the world's people. Cattle hides, used for leather to make shoes and clothing, are another widespread product. Cattle remain broadly used as draft animals in many developing countries, such as India.	A phylogeny of the extant ant subfamilies. "'Ants'" are social insects of the family "'Formicidae'", and along with the related wasps and bees, they belong to the order Hymenoptera. Ants evolved from wasp-like ancestors in the mid-Cretaceous period between 110 and 130 million years ago and diversified after the rise of flowering plants. Today, more than 12,000 species are classified with upper estimates of about 14,000 species. They are easily identified by their elbowed antennae and a distinctive node-like structure that forms a slender waist. Ants form colonies that range in size from a few dozen predatory individuals living in small natural cavities to highly organised colonies which may occupy large territories and consist of millions of individuals. These larger colonies consist mostly of sterile wingless females forming castes of "workers", "soldiers", or other specialised groups. Ant colonies also have some fertile males called "drones" and one or more fertile females called "queens". The colonies are sometimes described as superorganisms because ants appear to operate as a unified entity, collectively working together to support the colony. Ants have colonised almost every landmass on Earth. The only places lacking indigenous ants are Antarctica and certain remote or inhospitable islands. Ants thrive in most ecosystems, and may form 15–25% of the terrestrial animal biomass. Their success has been attributed to their social organisation and their ability to modify habitats, tap resources, and defend themselves. Their long co-evolution with other species has led to mimetic, commensal, parasitic, and mutualistic relationships. Ant societies have division of labour, communication between individuals, and an ability to solve complex problems. These parallels with human societies have long been an inspiration and subject of study. Many human cultures make use of ants in cuisine, medication and rituals. Some species are valued in their role as biological pest control agents. However, their ability to exploit resources brings ants into conflict with humans, as they can damage crops and invade buildings. Some species, such as the red imported fire ant, are regarded as invasive species, since they have establish themselves in new areas where they may be accidentally introduced. Taxonomy and evolution. The family Formicidae belongs to the order Hymenoptera, which also includes sawflies, bees and wasps. Ants evolved from a lineage within the vespoid wasps. Phylogenetic analysis suggests that ants arose in the mid-Cretaceous period about 110 to 130 million years ago. After the rise of flowering plants about 100 million years ago they diversified and assumed ecological dominance around 60 million years ago. In 1966, E. O. Wilson and his colleagues identified the fossil remains of an ant ("Sphecomyrma freyi") that lived in the Cretaceous period. The specimen, trapped in amber dating back to more than 80 million years ago, has features of both ants and wasps. "Sphecomyrma" was probably a ground forager but some suggest on the basis of groups such as the Leptanillinae and Martialinae that primitive ants were likely to have been predators under the soil surface. During the Cretaceous period, only a few species of primitive ants ranged widely on the Laurasian super-continent (the northern hemisphere). They were scarce in comparison to other insects, representing about 1% of the insect population. Ants became dominant after adaptive radiation at the beginning of the Tertiary period. By the Oligocene and Miocene ants had come to represent 20–40% of all insects found in major fossil deposits. Of the species that lived in the Eocene epoch, approximately one in ten genera survive to the present. Genera surviving today comprise 56% of the genera in Baltic amber fossils (early Oligocene), and 92% of the genera in Dominican amber fossils (apparently early Miocene). Termites, though sometimes called "white ants", are not ants and belong to the order Isoptera. The termites are actually more closely related to cockroaches and mantids. The fact that ants and termites are both eusocial came about by Convergent evolution. Velvet ants look like large ants, but are wingless female wasps. Etymology. The word "ant" is derived from "ante" of Middle English which is derived from "æmette" and "emmett" of Old English and is related to the Old High German "āmeiza" from which comes "Ameise", the German word for ant. The family name "Formicidae" is derived from the Latin "formīca" ("ant") from which derived Portuguese "formiga", Spanish "hormiga", Romanian "furnică", French "fourmi", etc. Distribution and diversity. Ants are found on all continents except Antarctica and only a few large islands such as Greenland, Iceland, parts of Polynesia and the Hawaiian Islands lack native ant species. Ants occupy a wide range of ecological niches, and are able to exploit a wide range of food resources either as direct or indirect herbivores, predators and scavengers. Most species are omnivorous generalists but a few are specialist feeders. Their ecological dominance may be measured by their biomass, and estimates in different environments suggest that they contribute 15–20% (on average and nearly 25% in the tropics) of the total terrestrial animal biomass, which exceeds that of the vertebrates. Ants range in size from. Their colours vary; most are red or black, green is less common, and some tropical species have a metallic lustre. More than 12,000 species are currently known (with upper estimates of about 14,000), with the greatest diversity in the tropics. Taxonomic studies continue to resolve the classification and systematics of ants. Online databases of ant species, including AntBase and the Hymenoptera Name Server, help to keep track of the known and newly described species. The relative ease with which ants can be sampled and studied in ecosystems has made them useful as indicator species in biodiversity studies. Morphology. Ants are distinct in their morphology from other insects in having elbowed antennae, metapleural glands, and a strong constriction of their second abdominal segment into a node-like petiole. The head, mesosoma and metasoma or gaster are the three distinct body segments. The petiole forms a narrow waist between their mesosoma (thorax plus the first abdominal segment, which is fused to it) and gaster (abdomen less the abdominal segments in the petiole). The petiole can be formed by one or two nodes (the second alone, or the second and third abdominal segments). Like other insects, ants have an exoskeleton, an external covering that provides a protective casing around the body and a point of attachment for muscles, in contrast to the internal skeletons of humans and other vertebrates. Insects do not have lungs; oxygen and other gases like carbon dioxide pass through their exoskeleton through tiny valves called spiracles. Insects also lack closed blood vessels; instead, they have a long, thin, perforated tube along the top of the body (called the "dorsal aorta") that functions like a heart, and pumps haemolymph towards the head, thus driving the circulation of the internal fluids. The nervous system consists of a ventral nerve cord that runs the length of the body, with several ganglia and branches along the way reaching into the extremities of the appendages. An ant's head contains many sensory organs. Like most insects, ants have compound eyes made from numerous tiny lenses attached together. Ants' eyes are good for acute movement detection but do not give a high resolution. They also have three small ocelli (simple eyes) on the top of the head that detect light levels and polarisation. Compared to vertebrates, most ants have poor-to-mediocre eyesight and a few subterranean species are completely blind. Some ants such as Australia's bulldog ant, however, have exceptional vision. Two antennae ("feelers") are attached to the head; these organs detect chemicals, air currents and vibrations; they are also used to transmit and receive signals through touch. The head has two strong jaws, the mandibles, used to carry food, manipulate objects, construct nests, and for defence. In some species a small pocket (infrabuccal chamber) inside the mouth stores food, so it can be passed to other ants or their larvae. All six legs are attached to the mesosoma ("thorax"). A hooked claw at the end of each leg helps ants to climb and hang onto surfaces. Most queens and male ants have wings; queens shed the wings after the nuptial flight, leaving visible stubs, a distinguishing feature of queens. However, wingless queens (ergatoids) and males occur in a few species. The metasoma (the "abdomen") of the ant houses important internal organs, including those of the reproductive, respiratory (tracheae) and excretory systems. Workers of many species have their egg-laying structures modified into stings that are used for subduing prey and defending their nests. Polymorphism. In the colonies of a few ant species, there are physical castes—workers in distinct size-classes, called minor, median, and major workers. Often the larger ants have disproportionately larger heads, and correspondingly stronger mandibles. Such individuals are sometimes called "soldier" ants because their stronger mandibles make them more effective in fighting, although they are still workers and their "duties" typically do not vary greatly from the minor or median workers. In a few species the median workers are absent, creating a sharp divide between the minors and majors. Weaver ants, for example, have a distinct bimodal size distribution. Some other species show continuous variation in the size of workers. The smallest and largest workers in "Pheidologeton diversus" show nearly a 500-fold difference in their dry-weights. Workers cannot mate; however, because of the haplodiploid sex-determination system in ants, workers of a number of species can lay unfertilised eggs that become fully fertile haploid males. The role of workers may change with their age and in some species, such as honeypot ants, young workers are fed until their gasters are distended, and act as living food storage vessels. These food storage workers are called "repletes". This polymorphism in morphology and behaviour of workers was initially thought to be determined by environmental factors such as nutrition and hormones which led to different developmental paths; however, genetic differences between worker castes have been noted in "Acromyrmex" sp. These polymorphisms are caused by relatively small genetic changes; differences in a single gene of "Solenopsis invicta" can decide whether the colony will have single or multiple queens. The Australian jack jumper ant ("Myrmecia pilosula"), has only a single pair of chromosomes (males have just one chromosome as they are haploid), the lowest number known for any animal, making it an interesting subject for studies in the genetics and developmental biology of social insects. Development and reproduction. The life of an ant starts from an egg. If the egg is fertilised, the progeny will be female (diploid); if not, it will be male (haploid). Ants develop by complete metamorphosis with the larval stages passing through a pupal stage before emerging as an adult. The larva is largely immobile and is fed and cared for by workers. Food is given to the larvae by trophallaxis, a process in which an ant regurgitates liquid food held in its crop. This is also how adults share food, stored in the "social stomach", among themselves. Larvae may also be provided with solid food such as trophic eggs, pieces of prey and seeds brought back by foraging workers and may even be transported directly to captured prey in some species. The larvae grow through a series of moults and enter the pupal stage. The pupa has the appendages free and not fused to the body as in a butterfly pupa. The differentiation into queens and workers (which are both female), and different castes of workers (when they exist), is determined by the nutrition the larvae obtain. Larvae and pupae need to be kept at fairly constant temperatures to ensure proper development, and so are often moved around the various brood chambers within the colony. A new worker spends the first few days of its adult life caring for the queen and young. It then graduates to digging and other nest work, and later to defending the nest and foraging. These changes are sometimes fairly sudden, and define what are called temporal castes. An explanation for the sequence is suggested by the high casualties involved in foraging, making it an acceptable risk only for ants that are older and are likely to die soon of natural causes. Most ant species have a system in which only the queen and breeding females have the ability to mate. Contrary to popular belief, some ant nests have multiple queens while others can exist without queens. Workers with the ability to reproduce are called "gamergates" and colonies that lack queens are then called gamergate colonies; colonies with queens are said to be queen-right. The winged male ants, called drones, emerge from pupae along with the breeding females (although some species, like army ants, have wingless queens), and do nothing in life except eat and mate. During the short breeding period, the reproductives, excluding the colony queen, are carried outside where other colonies of similar species are doing the same. Then, all the winged breeding ants take flight. Mating occurs in flight and the males die shortly afterwards. Females of some species mate with multiple males. Mated females then seek a suitable place to begin a colony. There, they break off their wings and begin to lay and care for eggs. The females store the sperm they obtain during their nuptial flight to selectively fertilise future eggs. The first workers to hatch are weak and smaller than later workers, but they begin to serve the colony immediately. They enlarge the nest, forage for food and care for the other eggs. This is how new colonies start in most species. Species that have multiple queens may have a queen leaving the nest along with some workers to found a colony at a new site, a process akin to swarming in honeybees. Ant colonies can be long-lived. The queens can live for up to 30 years, and workers live from 1 to 3 years. Males, however, are more transitory, and survive only a few weeks. Ant queens are estimated to live 100 times longer than solitary insects of a similar size. Ants are active all year long in the tropics but, in cooler regions, survive the winter in a state of dormancy or inactivity. The forms of inactivity are varied and some temperate species have larvae going into the inactive state (diapause), while in others, the adults alone pass the winter in a state of reduced activity. Communication. Ants communicate with each other using pheromones. These chemical signals are more developed in ants than in other hymenopteran groups. Like other insects, ants perceive smells with their long, thin and mobile antennae. The paired antennae provide information about the direction and intensity of scents. Since most ants live on the ground, they use the soil surface to leave pheromone trails that can be followed by other ants. In species that forage in groups, a forager that finds food marks a trail on the way back to the colony; this trail is followed by other ants, these ants then reinforce the trail when they head back with food to the colony. When the food source is exhausted, no new trails are marked by returning ants and the scent slowly dissipates. This behaviour helps ants deal with changes in their environment. For instance, when an established path to a food source is blocked by an obstacle, the foragers leave the path to explore new routes. If an ant is successful, it leaves a new trail marking the shortest route on its return. Successful trails are followed by more ants, reinforcing better routes and gradually finding the best path. Ants use pheromones for more than just making trails. A crushed ant emits an alarm pheromone that sends nearby ants into an attack frenzy and attracts more ants from further away. Several ant species even use "propaganda pheromones" to confuse enemy ants and make them fight among themselves. Pheromones are produced by a wide range of structures including Dufour's glands, poison glands and glands on the hindgut, pygidium, rectum, sternum and hind tibia. Pheromones are also exchanged mixed with food and passed by trophallaxis, transferring information within the colony. This allows other ants to detect what task group ("e.g.", foraging or nest maintenance) other colony members belong to. In ant species with queen castes, workers begin to raise new queens in the colony when the dominant queen stops producing a specific pheromone. Some ants produce sounds by stridulation, using the gaster segments and their mandibles. Sounds may be used to communicate with colony members or with other species. Defence===. Ants attack and defend themselves by biting and, in many species, by stinging, often injecting or spraying chemicals like formic acid. Bullet ants ("Paraponera"), located in Central and South America, are considered to have the most painful sting of any insect, although it is usually not fatal to humans. This sting is given the highest rating on the Schmidt Sting Pain Index. The sting of Jack jumper ants can be fatal, and an antivenin has been developed. Fire ants, "Solenopsis" spp., are unique in having a poison sac containing piperidine alkaloids. Their stings are painful and can be dangerous to hypersensitive people. Trap-jaw ants of the genus "Odontomachus" are equipped with mandibles called trap-jaws, which snap shut faster than any other predatory appendages within the animal kingdom. One study of "Odontomachus bauri" recorded peak speeds of between 126 and 230 h (78 143 mph), with the jaws closing within 130 microseconds on average. The ants were also observed to use their jaws as a catapult to eject intruders or fling themselves backwards to escape a threat. Before the strike, the ant opens its mandibles extremely widely and locks them in this position by an internal mechanism. Energy is stored in a thick band of muscle and explosively released when triggered by the stimulation of sensory hairs on the inside of the mandibles. The mandibles also permit slow and fine movements for other tasks. Trap-jaws are also seen in the following genera: "Anochetus", "Orectognathus", and "Strumigenys", plus some members of the Dacetini tribe, which are viewed as examples of convergent evolution. In addition to defence against predators, ants need to protect their colonies from pathogens. Some worker ants maintain the hygiene of the colony and their activities include undertaking or "necrophory", the disposal of dead nest-mates. Oleic acid has been identified as the compound released by dead ants that triggers undertaking behaviour in "Atta mexicana". Nests may be protected from physical threats such as flooding and over-heating by elaborate nest architecture. Workers of "Cataulacus muticus", an arboreal species that lives in plant hollows, respond to flooding by drinking water inside the nest, and excreting it outside. Learning. Many animals can learn behaviours by imitation but ants may be the only group apart from mammals where interactive teaching has been observed. A knowledgeable forager of "Temnothorax albipennis" leads a naive nest-mate to newly discovered food by the excruciatingly slow process of tandem running. The follower obtains knowledge through its leading tutor. Both leader and follower are acutely sensitive to the progress of their partner with the leader slowing down when the follower lags, and speeding up when the follower gets too close. Controlled experiments with colonies of "Cerapachys biroi" suggest that individuals may choose nest roles based on their previous experience. An entire generation of identical workers was divided into two groups whose outcome in food foraging was controlled. One group was continually rewarded with prey, while it was made certain that the other failed. As a result, members of the successful group intensified their foraging attempts while the unsuccessful group ventured out less and less. A month later, the successful foragers continued in their role while the others moved to specialise in brood care. Nest construction. Complex nests are built by many ants, but other species are nomadic and do not build permanent structures. Ants may form subterranean nests or build them on trees. These nests can be found in the ground, under stones or logs, inside logs, hollow stems or even acorns. The materials used for construction include soil and plant matter, and ants carefully select their nest sites; "Temnothorax albipennis" will avoid sites with dead ants, as these may indicate the presence of pests or disease. They are quick to abandon established nests at the first sign of threats. The army ants of South America and the driver ants of Africa do not build permanent nests, but instead alternate between nomadism and stages where the workers form a temporary nest (bivouac) from their own bodies, by holding each other together. Weaver ant ("Oecophylla" spp.) workers build nests in trees by attaching leaves together, first pulling them together with bridges of workers and then inducing their larvae to produce silk as they are moved along the leaf edges. Similar forms of nest construction are seen in some species of "Polyrhachis". Food cultivation. Most ants are generalist predators, scavengers and indirect herbivores, but a few have evolved specialised ways of obtaining nutrition. Leafcutter ants ("Atta" and "Acromyrmex") feed exclusively on a fungus that grows only within their colonies. They continually collect leaves which are taken to the colony, cut into tiny pieces and placed in fungal gardens. Workers specialise in tasks according to their sizes. The largest ants cut stalks, smaller workers chew the leaves and the smallest tend the fungus. Leafcutter ants are sensitive enough to recognise the reaction of the fungus to different plant material, apparently detecting chemical signals from the fungus. If a particular type of leaf is toxic to the fungus the colony will no longer collect it. The ants feed on structures produced by the fungi called "gongylidia". Symbiotic bacteria on the exterior surface of the ants produce antibiotics that kill bacteria that may harm the fungi. Navigation. Foraging ants travel distances of up to from their nest and usually find their way back using scent trails. Some ants forage at night. Day foraging ants in hot and arid regions face death by desiccation, so the ability to find the shortest route back to the nest reduces that risk. Diurnal desert ants ("Cataglyphis fortis") use visual landmarks in combination with other cues to navigate. In the absence of visual landmarks, the closely related Sahara desert ant ("Cataglyphis bicolor") navigates by keeping track of direction as well as distance travelled, like an internal pedometer that counts how many steps they take in each direction. They integrate this information to find the shortest route back to their nest. Several species of ants are able to use the Earth's magnetic field. Ants' compound eyes have specialised cells that detect polarised light from the Sun, which is used to determine direction. Locomotion. Worker ants do not have wings and reproductive females lose their wings after their mating flights in order to begin their colonies. Therefore, unlike their wasp ancestors, most ants travel by walking. Some species are capable of leaping. For example, Jerdon's jumping ant ("Harpegnathos saltator") is able to jump by synchronising the action of its mid and hind pairs of legs. There are several species of gliding ant including "Cephalotes atratus"; this may be a common trait among most arboreal ants. Ants with this ability are able to control the direction of their descent while falling. Other species of ants can form chains to bridge gaps over water, underground, or through spaces in vegetation. Some species also form floating rafts that help them survive floods. These rafts may also have a role in allowing ants to colonise islands. "Polyrhachis sokolova", a species of ant found in Australian mangrove swamps, can swim and live in underwater nests. Since they lack gills, they breathe in trapped pockets of air in the submerged nests. Cooperation and competition. Not all ants have the same kind of societies. The Australian bulldog ants are among the biggest and most basal (primitive) of ants. Like virtually all ants they are eusocial, but their social behaviour is poorly developed compared to other species. Each individual hunts alone, using its large eyes instead of its chemical senses to find prey. Some species (such as "Tetramorium caespitum") attack and take over neighbouring ant colonies. Others are less expansionist but just as aggressive; they invade colonies to steal eggs or larvae, which they either eat or raise as workers slaves. Extreme specialists among these slave-raiding ants, such as the Amazon ants, are incapable of feeding themselves and need captured workers to survive. Ants identify kin and nestmates through their scent, which comes from hydrocarbon-laced secretions that coat their exoskeletons. If an ant is separated from its original colony, it will eventually lose the colony scent. Any ant that enters a colony without a matching scent will be attacked. Parasitic ant species enter the colonies of host ants and establish themselves as social parasites; species like "Strumigenys xenos" are entirely parasitic and do not have workers, but instead rely on the food gathered by their "Strumigenys perplexa" hosts. This form of parasitism is seen across many ant genera, but the parasitic ant is usually a species that is closely related to its host. A variety of methods are employed to enter the nest of the host ant. A parasitic queen can enter the host nest before the first brood has hatched, establishing herself prior to development of a colony scent. Other species use pheromones to confuse the host ants or to trick them into carrying the parasitic queen into the nest. Some simply fight their way into the nest. A conflict between the sexes of a species is seen in some species of ants with the reproductives apparently competing to produce offspring that are as closely related to them as possible. The most extreme form involves the production of clonal offspring. An extreme of sexual conflict is seen in "Wasmannia auropunctata", where the queens produce diploid daughters by thelytokous parthenogenesis and males produce clones by a process where a diploid egg loses its maternal contribution to produce haploid males that are clones of the father. Relationships with other organisms. The spider "Myrmarachne plataleoides" (here a female) mimics weaver ants to avoid predators. Ants form symbiotic associations with a range of species, including other ant species, other insects, plants, and fungi. They are preyed on by many animals and even certain fungi. Some arthropod species spend part of their lives within ant nests, either preying on ants, their larvae and eggs, consuming the ants' food stores, or avoiding predators. These inquilines can bear a close resemblance to ants. The nature of this ant mimicry (myrmecomorphy) varies, with some cases involving Batesian mimicry, where the mimic reduces the risk of predation. Others show Wasmannian mimicry, a form of mimicry seen only in inquilines. Aphids and other hemipteran insects secrete a sweet liquid called honeydew when they feed on plant sap. The sugars in honeydew are a high-energy food source, which many ant species collect. In some cases the aphids secrete the honeydew in response to the ants' tapping them with their antennae. The ants in turn keep predators away and will move the aphids between feeding locations. On migrating to a new area, many colonies will take the aphids with them, to ensure a continued supply of honeydew. Ants also tend mealybugs to harvest their honeydew. Mealybugs can become a serious pest of pineapples if ants are present to protect mealybugs from their natural enemies. Myrmecophilous (ant-loving) caterpillars of the family Lycaenidae (e.g., blues, coppers, or hairstreaks) are herded by the ants, led to feeding areas in the daytime, and brought inside the ants' nest at night. The caterpillars have a gland which secretes honeydew when the ants massage them. Some caterpillars produce vibrations and sounds that are perceived by the ants. Other caterpillars have evolved from ant-loving to ant-eating: these myrmecophagous caterpillars secrete a pheromone that makes the ants act as if the caterpillar is one of their own larvae. The caterpillar is then taken into the ants' nest where it feeds on the ant larvae. Fungus-growing ants that make up the tribe Attini, including leafcutter ants, cultivate certain species of fungus in the "Leucoagaricus" or "Leucocoprinus" genera of the Agaricaceae family. In this ant-fungus mutualism, both species depend on each other for survival. The ant "Allomerus decemarticulatus" has evolved a three-way association with the host plant "Hirtella physophora" (Chrysobalanaceae), and a sticky fungus which is used to trap their insect prey. Lemon ants make devil's gardens by killing surrounding plants with their stings and leaving a pure patch of lemon ant trees ("Duroia hirsuta"). This modification of the forest provides the ants with more nesting sites inside the stems of the "Duroia" trees. Some trees have extrafloral nectaries that provide food for ants, which in turn protect the plant from herbivorous insects. Species like the bullhorn acacia ("Acacia cornigera") in Central America have hollow thorns that house colonies of stinging ants ("Pseudomyrmex ferruginea") that defend the tree against insects, browsing mammals, and epiphytic vines. Isotopic labelling studies suggest that plants also obtain nitrogen from the symbiotic ants. In return, the ants obtain food from protein-lipid Beltian bodies. Another example of this type of ectosymbiosis comes from the "Macaranga" tree, which has stems adapted to house colonies of "Crematogaster" ants. Many tropical tree species have seeds that are dispersed by ants. Seed dispersal by ants or myrmecochory is widespread particularly in Africa and Australia. Some plants in fire-prone grassland systems are particularly dependent on ants for their survival and dispersal. Many ant-dispersed seeds have special external structures, elaiosomes, that are sought after by ants as food. A convergence, possibly a form of mimicry, is seen in the eggs of stick insects. They have an edible elaiosome-like structure and are taken into the ant nest where the young hatch. Ants prey on and obtain food from a number of social insects including other ants. Some species specialise in preying on termites ("Megaponera" and "Termitopone") while a few Cerapachyinae prey on other ants. Some termites form associations with certain ant species to keep away other predatory ant species.The tropical wasp "Mischocyttarus drewseni" coats the pedicel of its nest with an ant-repellant chemical. It is suggested that many tropical wasps may build their nests in trees and cover them to protect themselves from ants. Stingless bees ("Trigona" and "Melipona") use chemical defences against ants. Flies in the Old World genus "Bengalia" (Calliphoridae) prey on ants and are kleptoparasites, snatching prey or brood from the mandibles of adult ants. Wingless and legless females of the Malaysian phorid fly ("Vestigipoda myrmolarvoidea") live in the nests of ants of the genus "Aenictus" and are cared for by the ants. The fungus "Cordyceps" infects ants, causing them to climb up plants and sink their mandibles into plant tissue. The fungus kills the ant, grows on its remains, and produces a fruiting body. It appears that the fungus alters the behaviour of the ant to help disperse its spores. Strepsipteran parasites also manipulate their ant host to climb grass stems, to help the parasite find mates. A nematode ("Myrmeconema neotropicum") that infects canopy ants ("Cephalotes atratus") causes the black coloured gasters of workers to turn red. The parasite also alters the behaviour of the ant, and makes them carry their gasters high. The conspicuous red gasters are mistaken by birds for ripe fruits such as "Hyeronima alchorneoides" and eaten. The droppings of the bird are collected by other ants and fed to their young leading to the further spread of the nematode. South American poison dart frogs in the genus "Dendrobates" feed mainly on ants, and the toxins in their skin may come from the ants. Several South American antbirds follow army ants to feed on the insects that are flushed from cover by the foraging ants. This behaviour was once considered mutualistic, but later studies show that it is instead kleptoparastic, with the birds stealing prey. Birds indulge in a peculiar behaviour called anting that is as yet not fully understood. Here birds rest on ant nests, or pick and drop ants onto their wings and feathers; this may remove ectoparasites. Anteaters, pangolins and several marsupial species in Australia have special adaptations for living on a diet of ants. These adaptations include long, sticky tongues to capture ants and strong claws to break into ant nests. Brown bears ("Ursus arctos") have been found to feed on ants, and about 12%, 16%, and 4% of their faecal volume in spring, summer, and autumn, respectively, is composed of ants. Relationship with humans. Ants perform many ecological roles that are beneficial to humans, including the suppression of pest populations and aeration of the soil. The use of weaver ants in citrus cultivation in southern China is considered one of the oldest known applications of biological control. On the other hand, ants can become nuisances when they invade buildings, or cause economic losses. In some parts of the world (mainly Africa and South America), large ants, especially army ants, are used as surgical sutures. The wound is pressed together and ants are applied along it. The ant seizes the edges of the wound in its mandibles and locks in place. The body is then cut off and the head and mandibles remain in place to close the wound. Some ants of the family Ponerinae have toxic venom and are of medical importance. The species include "Paraponera clavata" ("Tocandira") and "Dinoponera" spp. (false "Tocandira"s) of South America and the "Myrmecia" ants of Australia. In South Africa, ants are used to help harvest rooibos ("Aspalathus linearis"), which are small seeds used to make a herbal tea. The plant disperses its seeds widely, making manual collection difficult. Black ants collect and store these and other seeds in their nest, where humans can gather them "en masse". Up to half a pound (200 g) of seeds can be collected from one ant-heap. As food. Ants and their larvae are eaten in different parts of the world. The eggs of two species of ants are the basis for the dish in Mexico known as "escamoles". They are considered a form of insect caviar and can sell for as much as USD 40 per pound (USD 90 kg) because they are seasonal and hard to find. In the Colombian department of Santander, "hormigas culonas" (roughly interpreted as "large-bottomed ants") "Atta laevigata" are toasted alive and eaten. In areas of India, and throughout Burma and Thailand, a paste of the green weaver ant ("Oecophylla smaragdina") is served as a condiment with curry. Weaver ant eggs and larvae as well as the ants themselves may be used in a Thai salad, "yum" (ยำ), in a dish called "yum khai mod daeng" (ยำไข่มดแดง) or red ant egg salad, a dish that comes from the Issan or north-eastern region of Thailand. Saville-Kent, in the "Naturalist in Australia" wrote "Beauty, in the case of the green ant, is more than skin-deep. Their attractive, almost sweetmeat-like translucency possibly invited the first essays at their consumption by the human species". Mashed up in water, after the manner of lemon squash, "these ants form a pleasant acid drink which is held in high favor by the natives of North Queensland, and is even appreciated by many European palates". In his "First Summer in the Sierra", John Muir notes that the Digger Indians of California ate the tickly acid gasters of the large jet-black carpenter ants. The Mexican Indians eat the replete workers, or living honey-pots, of the honey ant ("Myrmecocystus"). As pests. Some ant species are considered pests, and because of the adaptive nature of ant colonies, eliminating the entire colony is nearly impossible. Pest management is therefore a matter of controlling local populations, instead of eliminating an entire colony, and most attempts at control are temporary solutions. Ants classified as pests include the pavement ant, yellow crazy ant, sugar ants, the Pharaoh ant, carpenter ants, Argentine ant, odorous house ants, red imported fire ant and European fire ant. Populations are controlled using insecticide baits, either in granule or liquid formulations. Bait is gathered by the ants as food and brought back to the nest where the poison is inadvertently spread to other colony members through trophallaxis. Boric acid and borax are often used as insecticides that are relatively safe for humans. Bait may be broadcast over a large area to control species like the red fire ant that occupy large areas. Nests of red fire ants may be destroyed by following the ants' trails back to the nest and then pouring boiling water into it to kill the queen. This works in about 60% of the mounds and requires about per mound. In science and technology. Myrmecologists study ants in the laboratory and in their natural conditions. Their complex and variable social structures have made ants ideal model organisms. Studies on ants have tested hypotheses in ecology, sociobiology and have been particularly important in examining the predictions of theories of kin selection and evolutionarily stable strategies. Ant colonies can be studied by rearing or temporarily maintaining them in formicaria, specially constructed glass framed enclosures. Individuals may be tracked for study by marking them with colours. The successful techniques used by ant colonies have been studied in computer science and robotics to produce distributed and fault-tolerant systems for solving problems. This area of biomimetics has led to studies of ant locomotion, search engines that make use of "foraging trails", fault-tolerant storage and networking algorithms. In culture. Ants have often been used in fables and children's stories to represent industriousness and cooperative effort. They are also mentioned in religious texts. In the Book of Proverbs in the Bible, ants are held up as a good example for humans for their hard work and cooperation. Aesop did the same in his fable The Ant and the Grasshopper. In parts of Africa, ants are considered to be the messengers of the gods. Ant bites are often said to have curative properties. The sting of some species of "Pseudomyrmex" is claimed to give fever relief. Some Native American mythology, such as the Hopi mythology, considers ants as the very first animals. Others use ant bites in initiation ceremonies as a test of endurance. Ant society has always fascinated humans and has been written about both humorously and seriously. Mark Twain wrote about ants in his "A Tramp Abroad". Some modern authors have used the example of the ants to comment on the relationship between society and the individual. Examples are Robert Frost in his poem "Departmental" and T. H. White in his fantasy novel "The Once and Future King". The plot in French entomologist and writer Bernard Werber's "Les Fourmis" science-fiction trilogy is divided between the worlds of ants and humans; ants and their behaviour is described using contemporary scientific knowledge. In more recent times, animated cartoons and 3D animated movies featuring ants have been produced include "Antz", "A Bug's Life", "The Ant Bully", "The Ant and the Aardvark", "Atom Ant", and there is a comic book superhero called Ant-Man. From the late 1950s through the late 1970s, ant farms were popular educational children's toys in the United States. Later versions use transparent gel instead of soil allowing greater visibility. In the early 1990s, the video game SimAnt, which simulated an ant colony, won the 1992 Codie award for "Best Simulation Program". Ants are also quite popular inspiration for many science-fiction creatures, such as the Formics of "Ender's Game", the Bugs of "Starship Troopers", the giant ants in the film "Them!", and ants mutated into super intelligence in "Phase IV". In strategy games, ant-based species often benefit from increased production rates due to their single-minded focus, such as the Klackons in the "Master of Orion" series of games or the ChCht in "Deadlock II". These characters are often credited with a hive mind, a common misconception about ant colonies.