SEP 05, 2017 07:55 AM PDT

The Case of the Sex-changing Crocodiles

WRITTEN BY: Carmen Leitch

Researchers, including physiological ecologist Chris Murray, are trying to figure out what is changing the sex of crocodiles in Costa Rica. They found that the population is becoming skewed towards males, with an assessment finding that male hatchlings were outnumbering females three or four to one, depending on the study.

It was suspected that a hormone, 17α-methyltestosterone (MT), could be to blame for this change. The investigators began to speculate on where could it be coming from since the primary users of the drug are older breast cancer patients or men with a testosterone deficiency. It seems that fish farms raising tilapia nearby are using it; the drug makes more male than female tilapia, generating higher profits for the fish farms.

After the researchers tested the drug in the laboratory, they found that "MT does have a masculinizing effect" on crocodilians, said Murray. The source remains a question, however. Ecologist Frank Chapman noted that if it is the farms, it is a reversible effect. Check out the video to learn more.
About the Author
  • Experienced research scientist and technical expert with authorships on 28 peer-reviewed publications, traveler to over 60 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
You May Also Like
NOV 12, 2019
Space & Astronomy
NOV 12, 2019
Here's What We've Learned About Jupiter From Juno So Far
It seems like it wasn’t too long ago that NASA’s Juno spacecraft entered orbit around Jupiter, but don’t be fooled, as the spacecraft has...
NOV 12, 2019
Chemistry & Physics
NOV 12, 2019
Ultra-dark Material Constructed with Carbon Nanotubes
The reason why we can "see" is because when light rays strike an object, a portion of them get reflected at its surface and enter into our eyes....
NOV 12, 2019
Chemistry & Physics
NOV 12, 2019
Is the Milky Way Too "Gassy"?
Astrophysicists have long thought that our home galaxy the Milky Way has been constantly losing mass due to the escape of hydrogen gas. However, by observi...
NOV 12, 2019
Earth & The Environment
NOV 12, 2019
Pesticides Plague Great Barrier Reef Waterways
Based on parameters set by the Australian and Queensland Governments, a significant pesticide reduction target for waters entering for the Great Barrier Re...
NOV 12, 2019
Plants & Animals
NOV 12, 2019
The Penguin Life Isn't Always Easy
Mother nature isn’t kind to wildlife; many assume their position as either the prey or the predator depending on the cards they’re dealt. Unfor...
NOV 12, 2019
Plants & Animals
NOV 12, 2019
Polar Bears Feast On Anything They Find, Even Rotting Whales
Polar bears are expert survivalists. Their noses are many times more powerful than a dog’s, and they can sniff out a potential meal from several mile...
Loading Comments...