A less demanding alternative to reading the lengthy historical explanations is a one-hour tape-recorded tour, narrated by Ruby Dee and Ossie Davis, that moves you through the museum at a brisker pace.

The tours, narrated by an Audubon naturalist, sell soft drinks and wine, and if storms strike, the enclosed, air-conditioned lower decks have monitors showing bird videos.

The exhibition, from April 7 to Sept. 3, will have an audio tour narrated by Mr. Martin from a script by Adam Gopnik, a writer for The New Yorker.

"Nature's Pharmacy: Plants That Heal," an exhibition featuring medicinal and economically important plants in the Haupt Conservatory, including an audio tour narrated by garden scientists; through Sunday.

"For some people, taking an audio tour narrated by an academic person is intimidating," said Elizabeth Addison, the museum's deputy director for marketing and communications.

Free audio guided tour of the Museum collection, narrated by the founder, is available upon admission.

You might be able to choose the tour narrated by Philippe de Montebello, your teen-aged son could get one narrated by Michael Jordan, and the toddler could get Kermit the Frog.

The tour, narrated in German, leaves at 12:10 p.m. daily and takes about two hours ($7.30).

The podcasts, which will be posted every Thursday through October, also feature driving tours narrated by the magazine's travel editors.

An audio tour for cell phones and media players, narrated by Bill Nye, was added in 2003, and the Asteroid station, featuring a real meteorite, was added in 2009.