Mason is a chimpanzee that resides in the Central Park Zoo with his fellow chimpanzee Phil. He has dark brown fur, and serves as Phil's interpreter. He is the "Felix" of the Chimpanzees, being a fine and neat gentleman which is opposite to Phil's attitude. Their difference doesn't entirely affect their friendship.
Mason is a very intelligent chimp who speaks with a British accent, though according to Private in Truth Ache, he is actually Canadian. He enjoys the finer things in life such as poetry, fine cuisine and art work, along with throwing poo at people. However, unlike Phil, he is illiterate. He is the darker colored of the two chimps.