To view this video please enable JavaScript, and consider upgrading to a web browser that supports HTML5 video Movie S1 Swimming behavior of a tadpole in the electric chamber after delivery of electric shock filmed using a high-speed camera. The constant threat from a non-native predator increases tail muscle and fast-start swimming performance in Xenopus tadpoles Tsukasa Mori, Yukio Yanagisawa, Yoichiro Kitani, Goshi Yamamoto, Naoko Goto-Inoue, Tadashi Kimura, Keiko Kashiwagi, and Akihiko Kashiwagi Biology Open 2017. 6:1726-1733; doi: 10.1242/bio.029926 Download Original Video