Charles Ellsworth Kern Jr., 75, the son of a D.C. zookeeper, the owner of a Washington heating and air-conditioning company and a supernumerary for three opera companies, died of a stroke July 26 at his home in McLean.

Mr. Kern, a native Washingtonian, told his children that his family survived the Depression by eating overripe bananas left by the apes at the National Zoo. His father let him swim in the painted hippopotamus tank before the hippos did, and Mr. Kern wrestled with a baby orangutan and baby gorilla before they got too big.

He worked as a newsboy in the 1940s, selling The Washington Post on the corner of Mount Pleasant Street and Park Road NW. He ran on the Central High School track team and served in the U.S. Naval Air Reserve Force after World War II.

After taking courses at the U.S. Merchant Marine Academy and George Washington University, Mr. Kern worked at Washington Gas Light Co. in the 1950s and at the Krafft Co. in the 1960s. In 1976, he formed Kern Co., which installed heating and air-conditioning systems in large buildings and private homes in the District and Virginia.

An expert draftsman, he drew blueprints by hand and refused to use computer programs. In semi-retirement since 2000, he found that many builders still needed the services of someone with knowledge of old-school ducts. His blueprints sometimes were digitized so that younger engineers could use them. Mr. Kern acted as a consultant when the digital systems failed.

Mr. Kern was devoted to classical music and tried for years to master the French horn. In 1980, he answered a call for nonspeaking opera actors and became a regular performer in productions of the Washington National Opera, the Opera Theatre of Northern Virginia and the Metropolitan Opera when it performed at the John F. Kennedy Center for the Performing Arts. He had only one role in which he spoke -- when he appeared on stage in a dog costume. His single line was: "Arf! Arf!"

He appeared in 65 productions and kept extensive written and photographic records of each of his 334 performances.

For a 1993 performance of Robert Kurka's "The Good Soldier Schweik," Mr. Kern told relatives that he played multiple parts that involved "running, falling, crawling, fighting, throwing people down and across tables and out of wheelchairs."

He idolized Leonard Bernstein, exchanged jokes with Placido Domingo and could not help blushing in the presence of beautiful sopranos, whom he sometimes had to carry offstage.

He relished the Northern Virginia children's operas because he could look out from his costume and see the kids' faces.

Mr. Kern loved the Washington area and chronicled its architectural changes with his camera. As an adult, he supported Friends of the National Zoo, known as FONZ, but he otherwise opposed acronyms. He once stood in front of the MCI building asking people going in and out what the letters meant. No one knew. (According to MCI's spokeswoman, it originally stood for Microwave Communications Inc.)

His wife of 51 years, Barbara Dalton, died in 2001. A daughter, Carolyn Kern de Santiago, died in 1989.

Survivors include his daughter, Audrey McGlynn of Manassas; his mother, Elizabeth Haddock of Panama City, Fla.; two sisters; a brother; and seven grandchildren.

Charles Ellsworth Kern Jr., 75, was a nonspeaking opera performer.