Mexican authorities and organizations helping to process the influx of migrants from the Central American caravan have resorted to assigning numbers to each migrant and writing the number on the individual’s wrist, Yahoo News reports. The numbers are reportedly used as an identifying tool to keep track of where migrants are on an ever-growing waitlist to cross the U.S. border. The Mexican government reportedly forced migrants from camps near cross-border bridges to more permanent shelters, where Customs and Border Protection agents tell local authorities and groups how many migrants may cross into the United States and when. In places like Juarez, the waitlist to enter the U.S. is reportedly weeks-long. In Tijuana, the website reports the waitlist is months-long. “It’s how you would mark an animal,” Alex Varela, a former U.S. Marine who helped a family get on the waiting list at Casa del Migrante, said of the identifying numbers. The family of three Varela helped were assigned the numbers 1173, 1174, and 1175.