The biologist Raquel Monclús, who carried out the study during a postdoctoral research at the University of California (USA) and is currently a researcher at the Autonomous University of Madrid, discovered in her experiments that themale yellow-bellied marmots ( Marmota flaviventris )they secrete testosterone into the uterus very early, which is absorbed by females, who do not begin to produce estrogen until a long time later. As a consequence, these females present morphological and behavioral differences with respect to their congeners of the same sex.
On the one hand, to sex these rodents, the distance between the genital papilla and the anus is measured, which is greater in males. However, among females exposed to high concentrations of testosterone in the maternal uterus, the distance between the vulva and the anus is intermediate.
In addition to these physical characteristics,masculinized marmots are more aggressive, adventurous, and playful. And they don’t allow copulation, so they don’t have offspring. Unlike their sisters who stay in the burrow to help their mothers care for the new hatchlings, theythey move away from the group like the males, forced by the dominant to abandon it.
According to the scientists, the results of the study can help to better understand the influence of certain environmental chemical compounds on theendocrine disruptorsof mammals.
