Scientific research suggests that amphibian malformations can be caused by a variety of abiotic and biotic agents in the environment. It is likely that many of these factors work together to cause abnormalities in amphibians, e.g., parasite infection and chemical toxins in the water. Moreover, studies have shown that these various agents likely vary in importance across sites and years, and no single cause is likely to explain all high-frequency accounts of amphibian deformities in nature.
The amphibian malformation phenomenon and potential implications for human health and wildlife conservation remain a topic of intense scientific debate and controversy. Below, we review available evidence for the best-supported potential causes of amphibian abnormalities.