Sexing Short-Tailed Opossums
Male or Female?
By Molly Kalafut
My male short-tailed opossum displaying his manly bits
Generally anyone asking how to tell the difference between male and female STO probably has a girl...because if you have a boy you will know!
The differences between male and female STO are very easy to see. The male's testicles become visible as early as 7 days after birth, and develop to be large, furred and very noticeable. They can be seen on males from underneath, the side or the back.
Female
Females have a smooth opening near the tail. (View from underneath)
Male
Males have large, furry testicles near the tail. (View from side & underneath)
