In his 1975 book, Animal Liberation, Australian philosopher Peter Singer writes that the “tyranny of human over nonhuman animals” is “causing an amount of pain and suffering that can only be compared with that which resulted from the centuries of tyranny by white humans over black humans.”

Singer favorably compares animal liberation with women’s liberation, black liberation, gay liberation and movements on behalf of Native Americans and Hispanics. He optimistically observes: “...the environmental movement...has led people to think about our relations with other animals in a way that seemed impossible only a decade ago.

"To date, environmentalists have been more concerned with wildlife and endangered species than with animals in general, but it is not too big a jump from the thought that it is wrong to treat whales as giant vessels filled with oil and blubber to the thought that it is wrong to treat (animals) as machines for converting grains to flesh.”

Supporters of civil rights should be supportive of animal rights. Many of the moral and theological arguments used today to oppress animals were once used to oppress blacks. Buckner H. Payne, calling himself “Ariel,” wrote in 1867, that “the tempter in the Garden of Eden...was a beast, a talking beast...the negro.” Ariel argued that since the negro was not part of Noah’s family, he must have been a beast. Eight souls were saved on the ark, therefore, the negro must be a beast, and “consequently he has no soul to be saved.”

In her preface to Marjorie Spiegel’s The Dreaded Comparison: Human and Animal Slavery, Alice Walker, author of The Color Purple, agrees with Ms. Spiegel's position, writing: “The animals of this world exist for their own reasons. They were not made for humans any more than black people were made for whites or women for men...”

Ms. Spiegel writes that at a rally in San Francisco protesting the use of animals in medical research, former Alameda County supervisor John George said, “My people were the first laboratory animals in America.” Black Americans suffered at the hands of research scientists just as animals continue to do today.

In 1968, civil rights leader Dick Gregory compared humanity’s treatment of animals to the conditions of America’s inner cities:

“Animals and humans suffer and die alike. If you had to kill your own hog before you ate it, most likely you would not be able to do it. To hear the hog scream, to see the blood spill, to see the baby being taken away from its momma, and to see the look of death in the animal’s eye would turn your stomach. So you get the man at the packing house to do the killing for you.

“In like manner, if the wealthy aristocrats who are perpetuating conditions in the ghetto actually heard the screams of ghetto suffering, or saw the slow death of hungry little kids, or witnessed the strangulation of manhood and dignity, they could not continue the killing. But the wealthy are protected from such horror...If you can justify killing to eat meat, you can justify the conditions of the ghetto. I cannot justify either one.”

Gregory credits the Judeo-Christian ethic and the teachings of Dr. Martin Luther King, Jr. with having caused him to become a vegetarian. In 1973, he drew a connection between vegetarianism and nonviolent civil disobedience:

"...the philosophy of nonviolence, which I learned from Dr. Martin Luther King, Jr. during my involvement in the civil rights movement was first responsible for my change in diet. I became a vegetarian in 1965. I had been a participant in all of the ‘major’ and most of the ‘minor’ civil rights demonstrations of the early sixties, including the March on Washington and the Selma to Montgomery March.

“Under the leadership of Dr. King, I became totally committed to nonviolence, and I was convinced that nonviolence meant opposition to killing in any form. I felt the commandment ‘Thou shalt not kill’ applied to human beings not only in their dealings with each other—war, lynching, assassination, murder and the like—but in their practice of killing animals for food or sport. Animals and humans suffer and die alike...Violence causes the same pain, the same spilling of blood, the same stench of death, the same arrogant, cruel and brutal taking of life.”

In a 1979 interview, Gregory explained: “Because of the civil rights movement, I decided I couldn’t be thoroughly nonviolent and participate in the destruction of animals for my dinner...I didn’t become a vegetarian for health reasons; I became a vegetarian strictly for moral reasons... Vegetarianism will definitely become a people’s movement.”

When asked if humans will ultimately have to answer to a Supreme Being for their exploitation of animals, Gregory replied, “I think we answer for that every time we go to the hospital with cancer and other diseases.”

Gregory has also expressed the opinion that the plight of the poor will improve as humans cease to slaughter animals: “I would say that the treatment of animals has something to do with the treatment of people. The Europeans have always regarded their slaves and the people they have colonized as animals.”

Since the 1980s, Dick Gregory has been involved in the anti-drug campaign. Bruce Friedrich of People for the Ethical Treatment of Animals (PETA) reported back in the '90s that under Gregory’s influence, Dexter Scott King—head of the Martin Luther King, Jr. Center for Nonviolence in Atlanta, and son of the slain civil rights leader—and King’s widow, Coretta Scott King, had both become committed vegetarians.

Peter Singer concludes in Animal Liberation that “by ceasing to rear and kill animals for food, we can make extra food available for humans that, properly distributed, would eliminate starvation and malnutrition from this planet. Animal liberation is human liberation, too.” The animal rights movement should be supported by all caring Americans.