Researchers have discovered that the amphipod crustacean, which is native to the Ponto-Caspian region, is not a true predator and only plays an indirect role in the massive species extinction of crustaceans in native waters. According to experimental results, the invasive killer shrimp actually drove native amphipods out of their hiding places, making them easy prey for the round goby, a species which also originates from the Black Sea.