Derek Lamb (1936-2005) was an Academy Award-winning animator who directed, wrote, and/or produced many shorts for the National Film Board of Canada. Lamb also contributed several inserts to Sesame Street.
Lamb's best known Sesame segment is the "Mad Goat Song," which he directed, designed, scored, and narrated (with John Canemaker doing the actual animation). The segment reworks the designs for the dog, cat, and goat from his 1964 short I Know an Old Lady Who Swallowed a Fly.
Another Lamb segment features the world famous talking dog. The stubborn dog stymies his trainer by refusing to say "Yes," saying only "No" instead.
Lamb's other work included animating the Edward Gorey-inspired cartoon titles for Mystery! (which Sesame Street spoofed in the intro to their Mysterious Theater sketches in the early 1990s) and serving as executive producer on Peep and the Big Wide World.