What causes deformities in frogs, toads, and other amphibians?

Malformed frogs first came to national attention in 1995. Since that time, reports of malformed frogs and other amphibians have increased dramatically. Malformations have been reported in at least 44 states and in more than 50 species of frogs and toads. Multiple limbs, missing limbs, and facial abnormalities are the main malformations seen.

Frog malformations are the result of environmental factors affecting development during early tadpole stages. The variations in malformation suggest multiple causes are involved in this worldwide problem; four major causes that have been identified include injuries from predators, a specific parasite (fluke), nutritional deficiencies, and contaminants.

Amphibians are good indicators of significant environmental changes. Amphibians, unlike people, breathe at least partly through their skin, which is constantly exposed to everything in their environment. Consequently, their bodies are much more sensitive to environmental factors such as disease, pollution, toxic chemicals, ultraviolet radiation, and habitat destruction. The worldwide occurrences of amphibian declines and deformities could be an early warning that some of our ecosystems, even seemingly pristine ones, are seriously out of balance.

Learn more: Amphibian Research and Monitoring Initiative (ARMI)