Mara 18 (also known as M-18 or MS-18) is a primarily-Latino criminal organization, with members largely from El Salvador, Guatemala, and Honduras.
La Mara 18 was created in Los Angeles, California. During the 1980s, there was a mass exodus of Salvadorans that fled the conditions following the El Salvadoran Civil War. Many of the Salvadorans who traveled to California were the target of existing gangs who preyed on immigrants.
To become a member of MS-18, typical initiation involved being "jumped in" and beaten by gang members for 18 seconds. Many factions of the gang have since done away with the initiation. Members of the gang were considered to be permanent participants until death, with the exception of becoming a "calmado" or "calmada", a reference to people who are still considered members but have retired from gang activities.
The typical age of new members to the gang in El Salvador is 12 years old, with some recruits as young as nine. The recruiting age has lowered over time to replace older members who have become incarcerated, and to circumvent harsh legal penalties which apply to non-minors. Under El Salvador's post-Civil War legal system, minors cannot be tried for crimes even as serious as murder, and may only be sent to juvenile detention facilities for rehabilitation.
The principal rivals of Mara 18 are Mara Salvatrucha, a gang that consists primarily of members from El Salvador. Members of Mara 18 are also involved in ongoing territorial wars in Mexico with Mara Salvatrucha, also known as MS-13. The rivalry is in part a struggle for control over railroad yards near Mexico's Southern borders, where undocumented Central Americans cross on their way to the United States. Skirmishes between the two gangs have become commonplace in the rail yard of Southern Mexico, as those areas are often used as routes by gang members that smuggle illegals into the United States.