Caption: Marmoset monkeys play with and groom one another in a marmoset monkey colony display in the lobby of the National Primate Research Center. A red tag indicates a female monkey of breeding age, while a blue tag indicates a male monkey of breeding age. Endocrinologist Toni Ziegler and colleagues have found that male monkeys of two different species - marmosets and tamarins - experience sympathetic symptoms of pregnancy when their mates are expecting offspring.
Photo by: Jeff Miller
Date: March 2005
High-resolution 300 DPI JPEG

Caption: Marmoset monkeys play with and groom one another in a marmoset monkey colony display in the lobby of the National Primate Research Center. A red tag indicates a female monkey of breeding age, while a blue tag indicates a male monkey of breeding age. Endocrinologist Toni Ziegler and colleagues have found that male monkeys of two different species - marmosets and tamarins - experience sympathetic symptoms of pregnancy when their mates are expecting offspring.
Photo by: Jeff Miller
Date: March 2005
High-resolution 300 DPI JPEG