Dumas was born in 1930 and started drawing when he was 9 years old, continuing to cartoon when he was in high school in his native Detroit.
"I used to get on the bus and go into downtown Detroit and sell cartoons to Teen magazine for $2," he remembers. "I really thought I had made it. I was aiming for The New Yorker and Saturday Evening Post." He finally was published in The New Yorker at age 26, and the Post at 30.
After finishing high school, he joined the Air Force and was stationed in Arizona. He remained in the Grand Canyon State to attend Arizona State University, where his cartoons poking fun at the university's football team and the board of regents led to his dismissal from the newspaper staff.
Dumas decided he wanted to be a writer, a cartoonist or both. He went to New York, where he eventually met Walker through a mutual friend. They would work together for more than 35 years.
Dumas has published "An Afternoon in Waterloo Park," a biography of his mother. Athletics is the pressure valve that allows Dumas to handle deadlines. He plays tennis three or four times per week during the summer, and handball twice a week year-round.
He has been the handball champion of Greenwich, Conn., more than 20 times since 1956. He won the state championship in 1971 and 1976, and the New England title in 1971.
He lives in Connecticut with his wife, Gail. The Dumases have three sons, Timothy, David and John.