A. Stanley Rand, 73, a Smithsonian staff scientist known for his research in herpetology, died of complications from cancer Nov. 14 at Johns Hopkins Hospital in Baltimore.

Dr. Rand spent 33 years in Panama at the Smithsonian Tropical Research Institute. His work on frogs and lizards built him an international reputation, colleagues said, and he made significant contributions in animal communication, territoriality, sexual selection and anti-predator systems.

A prolific writer, he published his first scientific article in 1944, when he was 12 years old and presumably assisting his father, a well-known ornithologist, in Canada. His next publication occurred in 1950, while he was working as an 18-year-old assistant in the division of amphibians and reptiles at the Field Museum of Natural History in Chicago. He wrote or edited more than 150 scientific journal articles and books, including "Ecology of a Tropical Forest: Seasonal Rhythms and Long-Term Changes" (1982) and "Iguanas of the World: Their Behavior, Ecology and Conservation" (1982). He established the tungara frog project in Gamboa, Panama, attracting numerous scientists and students from around the world.

His research on occasion burst out of the intensely observed world of scientific publications and into the mass media. His work was written up several times in the New York Times, including in a 1977 series on the creative process of scientific research. In 1995, his study on the evolving songs of tungara frogs attracted the attention of a Dallas Morning News writer, who waxed poetic over the mating calls of amphibians.

Dr. Rand was born in Seneca Falls, N.Y., the son of a world-traveled ornithologist father and herpetologist mother. He grew up in Lake Placid, Fla., Ottawa and Chesterton, Ind., and graduated from DePauw University in Greencastle, Ind.

He served in the Army from 1955 to 1957 in West Germany. In 1961, he received a doctoral degree from Harvard University. Dr. Rand met his future wife when both had summer jobs cataloguing salamanders at the Field Museum in Chicago. They married in 1961 and followed his research work to Jamaica and Brazil.

He started working in 1964 for the Tropical Research Institute. Resident naturalist Martin Moynihan had offered him a job over the phone, but connections between Brazil and Panama were so bad that Moynihan could not hear Dr. Rand's shouted acceptance. His introductory trip to Panama turned into field research when the scientists stopped at the historic Fort San Lorenzo. His colleague Neal G. Smith, accompanying Dr. Rand and Moynihan, described the scene:

"Stanley went into lizard mode. Martin and I followed him around like two kids. Stanley peered and then, like a chameleon tongue, out went his arm and slap! Martin was aghast but Stanley opened his hand and there was a (smiling) Anolis. Stanley pulled its dewlap out and then he started his speech. Martin looked anxious as Stanley placed the lizard back. No problem.

" 'Do you ever hurt them that . . . way?' said Martin. Nope. On we went. Slap again and again the same result with more natural history chatter. . . . As we got back to the car, Stanley trailed. Martin looked at me and in the jet-powered whisper of his said, 'Well, now we have a herpetologist.' And so we did. No seminars, no review boards, no job advertisements."

Dr. Rand was the Tropical Research Institute's assistant director from 1974 to 1979, when he was promoted to senior scientist, dedicating all his time to research and to encouraging students, visiting scientists and colleagues. He moved to Alexandria in 1997 upon his retirement but continued his research, returning to Panama each summer, and collected a wall full of pictures of his former students' babies. An intellectually curious man who, according to his wife, remembered everything he read, he could as easily discuss Greek mythology as natural history.

Survivors include his wife, Patricia Grubbs Rand of Alexandria; a son, Hugh Rand of Seattle; two daughters, Margaret Weaver of Erie, Pa., and Katherine Rand of Alexandria; a brother; and two granddaughters.

A. Stanley Rand spent 33 years in Panama at the Smithsonian Tropical Research Institute. A prolific writer, he published his first scientific article in 1944, when he was 12 years old.