A new study has found that exposure to the popular weed killer Roundup can alter the morphology of some amphibian species, triggering unexpected changes in body shape of young tadpoles. In a series of tests conducted in large outdoor tanks that mimicked wetland ecosystems, scientists at the University of Pittsburgh found that tadpoles exposed to caged predators developed larger tails — an expected adaptation to help the amphibians better escape the predators. But to their surprise, they found that exposure to Roundup, an herbicide produced by biotech giant Monsanto, induced the same change in two species of amphibians, and that exposure to a combination of the pesticide and predators caused the tadpoles’ tails to grow twice as large as normal. Since tadpoles alter their body shapes to match their environment, the scientists say an exaggerated adaptation that does not fit the environment could put a species at a disadvantage. The study was published in the journal Ecological Applications.