Date of Death: June 26, 1933

Tom and his sister Helene were the first twins born in the YLPB, and probably in captivity.

Date of Death: August, 14, 1948

Tom apparently died of heart failure. He was 15 years old.

Parents: Pan and Mona

Also Known: Yerkes describes Tom as "bold, aggressive, and venturesome...adaptable to new situations, trustful, and highly cooperative." He had the reputation of being an exceptionaly good subject in experiments.