In “Something is changing the sex of Costa Rican crocodiles,” Science Magazine interviewed Chris Murray regarding his recent work. Murray and his colleagues were hired to investigate a weird trend noticed in the crocodiles in Palo Verde. His team backed the trend: Male crocodiles suddenly (or, perhaps, not so suddenly) outnumbered female crocodiles 4:1. Also importantly, however, the scientists realized that the tissues of the animals had traces of a synthetic steroid.
“For more than 20 years, researchers have fretted about the effects of endocrine disruptors.” #bcsfh2o https://t.co/JJPhLii45Y
— Caroline Zuba (@zcscience) September 10, 2017
Interestingly, the researchers believe that the synthetic steroid, discovered to be the hormone MT, was causing the crocodiles to switch sex. They speculate that the source of the hormone comes from tilapia farms, but that it could also possibly come from pollution or sewage. The debate regarding the source of MT, the realization that the hormone has been found in crocodiles from Palo Verde National Park and the Tárcoles River presents numerous issues. Is the hormone affecting other marine life (like the tilapia, or other fish)? What does this contamination mean for crocodiles?
American crocodiles, according to the article, are considered vulnerable, and the Costa Rica area that these crocodiles call home is one of few places that the species really thrive. If the hormone affects reproduction, the crocodiles could be in big trouble. In addition, tensions between area residents and the nearby crocodiles are fairly tense. If the hormone alters the behavior of the crocodile (which is a possibility), it can further sour relations and leave the crocodile population in further danger.
I chose the article because it is an interesting piece about a problem discussed constantly today – the effect humans have on their environment. MT, a man-made steroid that is not biodegradable, is prescribed for those with breast cancer, menopause, or erectile dysfunction. The effects on animals like crocodiles and fish are fairly unknown, and vulnerable animal populations could be faced with a number of problems as a result. Such pollutants can have a world-wide impact.
