From his Humanity show; quoted in "Ricky Gervais chooses vegan," Vegetarians of Washington (13 September 2017) https://vegofwa.org/tag/ricky-gervais/
“Those who live with pigs often speak of them as we normally speak of dogs—intelligent, loyal, and above all, affectionate. Each one, I am continually reminded by people who know them, is a complete individual, like no other pig.”
Source: The Pig Who Sang to the Moon (2003), Ch. 1, p. 52
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Jeffrey Moussaieff Masson 42
American writer and activist 1941Related quotes
“ Mike White's 'Veggie Testimonial' https://www.youtube.com/watch?v=pF8PJJFgg4E”, ad for PETA (30 July 2009).
AronRa vs Ray Comfort (September 17th, 2012), Radio Paul's Radio Rants
“I am fond of pigs. Dogs look up to us. Cats look down on us. Pigs treat us as equals.”
                                        
                                        Christopher Soames, speech at the Reform Club (28 April 1981), reported in Martin S. Gilbert, Winston S. Churchill. Volume Eight: Never Despair: 1945–1965. p. 304 
Post-war years (1945–1955) 
Variant: I like pigs. Dogs look up to us. Cats look down on us. Pigs treat us as equals.  
Context: [Christopher Soames, Churchill's future son-in-law, remembered] Churchill showing him around Chartwell Farm [around 1946]. When they came to the piggery Churchill scratched one of the pigs and said: I am fond of pigs. Dogs look up to us. Cats look down on us. Pigs treat us as equals.
                                    
“Dogs do speak, but only to those who know how to listen.”
Source: My Name is Red
“The living owe it to those who no longer can speak to tell their story for them.”
Source: The Issa Valley