The animal welfare and rights movements grew in the 1970s with the publication of philosopher Peter Singer 's influential '' Animal Liberation '' , and Henry Spira 's successful and highly publicized campaigns against animal testing . The movements became more popular still with the founding of People for the Ethical Treatment of Animals ( PETA ) in 1980 and PETA 's years-long legal battle over the Silver Spring monkeys , 17 research macaques found to be living in welfare-compromised conditions in an undercover investigation by PETA 's Alex Pacheco
Silver Spring monkeys
Silver Spring monkeys
Animal welfare in the United States