Certain plant-based foods are high in estrogens, and certain types of plastics can leach synthetic estrogens into food and beverages. You’re likely aware of this, as it presents a health concern, and some steps have been taken to minimize the public’s exposure to such hormones. Too much of any hormone is a bad thing, including for humans, but in the case of frogs it is having a very peculiar effect…suburban frogs are turning female.
According to a new report, researchers sampled frogs from 21 ponds throughout Connecticut and found that female populations were high in the suburbs, but that ponds further out in the forests had more neutral population numbers. In addition, the researchers found that male frogs in affected ponds had intersex characteristics.
The researchers looked at Rana clamitans — green frogs — as they’re populous in the eastern US where the study took place. Synthetic estrogenic hormones, such as those from birth control pills, aren’t to blame, at least according to the report. Rather, suburban ponds were found to have high levels of phytoestrogens, which are estrogenic chemicals produced by plants (soy, for example).
That could be attributed to suburban landscaping habits, which could be allowing estrogenic plants to propagate in high numbers while reducing native flora. The exact source of the excessive chemicals isn’t known at this point, though the researchers say it could be coming from lawns, from leaking sewage systems, and more. Male frogs studied were found to have “female characteristics”, including hermaphroditic traits. This phenomenon could potentially affect other animals, as well.
Previous studies have shown similar effects from agricultural pesticides, among other things. This latest study was lead by Yale’s Professor of Ecology David Skelly.