Irish Travellers () are a traditionally nomadic people of Irish origin living predominantly in Ireland, Great Britain, and the United States. Among themselves, Travellers refer to themselves as Pavees. Derogatory terms are sometimes used to refer to them by non-Travellers, such as 'pikeys', 'knackers', and 'gypos'. In Irish, Travellers are called an Lucht Siúil (literally, "the walking people"). Many non-Travellers still use the term 'tinkers' which originally meant "tinsmiths", however this term is also considered derogatory.
The historical origins of Travellers as a group has been a subject of academic and popular debate. It was once widely believed that Travellers were descended from landowners or labourers who were made homeless by Oliver Cromwell's military campaign in Ireland and in the 1840s famine. However, their origins may be more complex and difficult to ascertain because through their history the Travellers have left no written records of their own. The closest to a legend of origin known to exist describes the Travellers as descended from a tinsmith who helped build the cross on which Jesus Christ was crucified. According to this tale, Christ cursed the tinsmith's line to wander the earth until Judgment Day; compare Matthew 16:28 and the legend of the Wandering Jew.
Furthermore, not all families of the Travellers date back to the same point in time; some adopted Traveller customs centuries ago while others did so in more modern times, yet all claim ancient origins regardless of noted assumption of the habits and customs.
Dr. Sharon Gmelch, who has studied and written about the Travellers, states that the Dooley Clan is acknowledged by other Travellers as one of the "oldest families on the road". There are also many Irish people surnamed Dooley who are not Travellers.
Irish Travellers are considered to be part of the general Irish population, as indicated by their surnames. Genetic studies by Miriam Murphy, David Croke, and other researchers identified certain genetic diseases such as Galactosemia that are more common in the Irish Traveller population, involving identifiable allelic mutations that are rarer among the rest of the community. Two main hypotheses had arisen, speculating whether: 1) this resulted from marriages made largely within and among the Traveller community, or 2) suggesting descent from either an original Irish carrier long ago with ancestors unrelated to the rest of the Irish population. They concluded that: The fact that Q188R is the sole mutant allele among the Travellers as compared to the non-Traveller group may be the result of a founder effect in the isolation of a small group of the Irish population from their peers as founders of the Traveller sub-population. This would favour the second, endogenous, hypothesis of Traveller origins. No estimate was given for the date of the original mutation, but it is now clear that it mutated from other galactosemia-causing mutations that are found within the larger Irish population.
Irish Travellers distinguish themselves from the settled communities of the countries in which they live by their own language and customs. The language is known as Shelta, and there are two dialects of this language, Gammon (or Gamin) and Cant. It has been dated back to the eighteenth century, but may be older than that.
Travellers are keen breeders of dogs such as greyhounds and lurchers. They also have a long-standing interest in horse trading, and the main fairs associated with them are held annually at Ballinasloe in Ireland and Appleby in the U.K.
Irish Travellers are recognised in British law as an ethnic group. Ireland, however, does not recognise them as an ethnic group; rather, their legal status is that of a "social group". An ethnic group is defined as one whose members identify with each other, usually on the basis of a presumed common genealogy or ancestry. Ethnic identity is also marked by the recognition from others of a group's distinctiveness and by common cultural, linguistic, religious, behavioural or biological traits.
In Ireland and in Britain, Travellers are often referred to as "gypsies", "diddycoy", "tinkers" or "knackers" (although many now consider these terms offensive). These terms refer to services that were traditionally provided by the Travellers—tinkering (or tinsmithing) being the mending of tin ware such as pots and pans, and knackering being the acquisition of dead or old horses for slaughter. Irish Travellers are sometimes referred to as Gypsies in Ireland and in Britain (the term more accurately refers to the Roma people, represented in Britain by the Romanichal and Kale). The derogatory terms pikey and gyppo (derived from Gypsy) are also heard in Great Britain while the Cockney term creamer (from the rhyming slang "cream cracker", itself from knacker) is occasionally used in Ireland. "Diddycoy" is a Roma term for a child of mixed Roma and non-Roma parentage; as applied to the Travellers, it refers to the fact that they are not "Gypsy" by blood but have adopted a similar lifestyle.
A 2007 report published in Ireland states that over half of Travellers do not live past the age of 39 years. 
Travellers are noted for their propensity to violent feuding, which often result in pitched battles in towns, causing major damage and terrifying local people.              
A complaint against Travellers in the United Kingdom is that of unauthorised Traveller sites being established on privately owned land or on council-owned land not designated for that purpose. Under the government's "Gypsy and Traveller Sites Grant", designated sites for Travellers' use are provided by the council, and funds are made available to local authorities for the construction of new sites and maintenance and extension of existing sites. However, Travellers also frequently make use of other, non-authorised sites, including public "common land" and private plots, including large fields. Travellers claim that there is an under-provision of authorised sites—the Gypsy Council estimates an under-provision amounts to insufficient sites for 3,500 people—and that their use of non-authorised sites as an alternative is unavoidable.
An October 11, 2002 Dateline NBC episode reported that American Travellers habitually defraud their neighbours, demanding high prices for substandard day labour. A consequent investigation by South Carolina law enforcement resulted in a single conviction for fraud and a handful of truancy violations.
The Georgia Governor's Office of Consumer Affairs issued a press release on March 14 2007 titled "Irish Travelers Perpetuate a Tradition of Fraud".
Traveller advocates, along with the Commission for Racial Equality in the UK, counter that Travellers are a distinct ethnic group with an ancient history and claim that there is no statistical evidence that Traveller presence raises or lowers the local crime rate.
The struggle for equal rights for these transient people led to the passing of the Caravan Sites Act 1968 that for some time safeguarded their rights, lifestyle and culture in the UK. The Criminal Justice and Public Order Act 1994, however, repealed part II of the 1968 act, removing the duty on local authorities in the UK to provide sites for Travellers and giving them the power to close down existing sites.
Recent criticism against Travellers in the UK centers on Travellers who have bought land, built amenities without planning permission, then fought eviction attempts by claiming it would be an abuse of human rights to remove them from their homes. The families applied for retrospective planning permission whilst they were living on their land. This received much media attention during the British 2005 General Election.
The use of retrospective planning permission arose after the Criminal Justice and Public Order Act 1994, which Michael Howard brought through the Commons, started closing down many of the sites originally provided for the community. Howard advised that Travellers should buy their own land instead and assurances were made that they would be allowed to settle it, despite allegations that Travellers find it difficult to secure planning permission approval.
It has long been recognised that the health of Irish Travellers is significantly poorer than that of the general population in Ireland. This is evidenced in a lower life expectancy. A government report of 1987 found:
From birth to old age, they have high mortality rates, particularly from accidents, metabolic and congenital problems, but also from other major causes of death. Female Travellers have especially high mortality compared to settled women. 
In 2007, the Department of Health and Children in the Republic of Ireland, in conjunction with the Department of Health, Social Services and Public Safety in Northern Ireland, commissioned the University College Dublin School of Public Health and Population Science to conduct a major cross-border study of Travellers' welfare. The Study, including a detailed census of Traveller population and an examination of their health status, is expected to take up to three years to complete.
An exact figure for the Traveller population in Ireland is unknown. A national census in 2006 put the figure in Ireland at 22,400 constituting just over 0.5 percent of the Irish population. However much concern has been expressed that this figure does not represent the true size of the Traveller population. In addition to Ireland, Travellers live in other parts of the world. The number of Travellers living in Great Britain is uncertain, with estimations ranging between 15,000 and 30,000. A further 7,000 live in the USA. For example, a population of Irish Travellers lives in Murphy Village, South Carolina and the Fort Worth suburb of White Settlement, TX. 
From the 2006 Irish census it was determined that 20,975 dwell in urban areas and 1,460 were living in rural areas. With an overall population of just 0.5% some areas were found to have a higher proportion, with Tuam, Galway Travellers constituting 7.71% of the population. There were found to be 9,301 Travellers in the 0-14 age range, comprising 41.5% and a further 3,406 of them were in the 15-24 age range, comprising 15.2%. Children of age range 0-17 comprised 48.7% of the Traveller population.
The birth rate of Irish Travellers has decreased since the 1990s, but they still have one of the highest birth rates in Europe. The birth rate for the Traveller community for the year 2005 was 33.32 per 1000, possibly the highest birth rate recorded for any community in Europe. By comparison, the Irish National Average was 15.0 in 2007.
On average there are 10 times more driving fatalities within the Traveller community. At 22%, this represents the most common cause of death among Traveller males. Roughly 10 times more infants die under the age of two, while a third of Travellers die before the age of 25. In addition, 80% of Travellers die before the age of 65. Some 10% of Traveller children die before their second birthday, compared to just 1% of the general population. In Ireland, 2.6% of all deaths in the total population were for people aged under 25, versus 32% for the Travellers.
Irish Travellers have been portrayed on numerous occasions in popular culture.
Drummond. A. (2007) Irish Travellers and the Criminal Justice Systems across the Island of Ireland, PhD University of Ulster
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