Sylvia Howe Thompson, 52, a teacher and naturalist, died by accidental drowning while kayaking in Piscataway Creek in Prince George's County. She was reported missing Nov. 6, and her body was found Nov. 8.

Mrs. Thompson was doing research for a book about kayaking in the Washington area. She had retired in the spring after 17 years as a science teacher at Beauvoir, the National Cathedral Elementary School.

She was born in Boston and graduated from Smith College in Northampton, Mass. She worked as a research assistant to Dr. T. Berry Brazelton at the Child Development Unit at Children's Hospital in Boston before turning to primatology, working in Cambridge, England, and Kenya.

In 1981, she entered Harvard University's doctoral program in biological anthropology and conducted field research on the mothering patterns of Hanuman langur monkeys in Rajasthan, India.

She moved to the Washington area and taught graduate anthropology courses at George Washington University in 1982. She then taught science at Stoddert Elementary School in the District before switching to Beauvoir in 1988. She taught second-graders how to dissect squid and prepare rudimentary lab reports and to follow the life cycle of the monarch butterfly and the seasonal evolutions of trees.

Mrs. Thompson was co-author of more than 40 "Kids Can Do" columns for Parent & Child magazine. Since 1994, she also had taught seminars on behalf of Children's Resources International, for primary and preschool teachers from eastern and central European countries, Haiti and South Africa.

Survivors include her husband of 24 years, D. Dodge Thompson of Washington; two daughters, Elizabeth Howe Thompson of Boston and Katherine Dodge Thompson of Cambridge, Mass.; her father, James Murray Howe of Cambridge, Mass.; and four brothers.

Sylvia Thompson taught science at two D.C. elementary schools and anthropology at George Washington University.