I asked PETA about a quote attributed to Ingrid Newkirk, PETA's president. Rabbi Avi Shafran of Agudath Israel used the quote this way in his recent article:
And then there are the folks at People for the Ethical Treatment of Animals, or PETA, who object to all killing of animals because, as Ingrid Newkirk, the group’s co-founder and president, famously put it, “a rat is a pig is a dog is a boy” - because of their belief, in other words, that animals are no different from humans.
Ms. Newkirk is incompletely quoted by Rabbi Shafran. The actual quote according to PETA's Bruce Friedrich reads:
As far as pain is concerned, a rat is a pig is a dog is a boy.
Mr. Friedrich writes points out that this is a statement of scientific truth. He then writes:
It continues to amaze me that people believe that Ingrid (or anyone) would argue that there are not differences across species. It's just the issue of pain capacity that she was discussing, in arguing that we need to consider all beings' pain and not trade inconsequential desires of the human species (e.g., palate preference) off against the most basic needs of other species (e.g., the need not to be confined immobile in your own excrement for your entire life, the need not to have your teeth ripped out without pain relief, the need not to be scalded to death, etc.).