Journal of Undergraduate Research


prenatal androgen exposure, temperament, anxiety, testosterone-mediated digit ratios, rhesus macaques


Family, Home, and Social Sciences




Prenatal androgen exposure (PAE) is the organizational force that masculinizes the brain. It has impact on other parts of the body as well. For example, PAE induces growth in the ring finger. Consequently, the pointer-to-ring-finger digit ratio (2D:4D ratio) is frequently used to assess PAE.1 Though this phenotype is sexually dimorphic, research indicates that PAE’s effect on digit ratio may be in the opposite direction when comparing humans and nonhuman primates.22 Very few studies have investigated 2D:4D ratio in rhesus macaques (Macacca mulatta), and to our knowledge, none have reported a sex difference in digit ratio. The purpose of this study is to investigate 2D:4D ratio in this species. We hypothesize that rhesus monkeys will display the nonhuman primate pattern of 2D:4D ratio, with males having higher digit ratio than females.

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