Before humans went into space, several other animals were launched into space, including numerous primates, so that scientists could investigate the biological effects of space travel. The United States launched flights containing primate cargo primarily between 1948-1961 with one flight in 1969 and one in 1985. France launched two monkey-carrying flights in 1967. The Soviet Union and Russia launched monkeys between 1983 and 1996. Most primates were anesthetized before lift-off. Overall thirty-two monkeys flew in the space program; none flew more than once. Numerous back-up monkeys also went through the programs but never flew. Monkeys and apes from several species were used, including rhesus monkeys, cynomolgus monkeys, squirrel monkeys, pig-tailed macaques, and chimpanzees.