Human Pollutants Are Leading to Endangered Frog Species

A study in a laboratory at Uppsala University in Sweden revealed the effects of estrogen on frogs and seems to explain why so many species of frog are facing possible extinction. Estrogen winds up in natural bodies of water after sewage is treated, but estrogen is not filtered out.

In the study, they discovered that male tadpoles were changed into females by exposing them to estrogen levels similar to what would be found in the environment.

This poses a threat to the frog population as more and more tadpoles are females and fewer tadpoles become males.