Caption: On June 16, 2008, an infant marmoset monkey clings to his father at the Wisconsin National Primate Research Center (WNPRC) at the University of Wisconsin-Madison. A new study by WNPRC scientist Toni Ziegler shows that the odor of their own offspring lowers testosterone levels in marmoset fathers.
Photo by: Jordana Lenon/WNPRC
Date: June 2008
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