The English have long been fascinated with nature, especially collecting and identifying their local flora and fauna. So the idea that any living thing — especially a vertebrate — anywhere in England could go unrecognized as a native species is quite astounding. But apparently, this is exactly what happened for the pool frog, Pelophylax lessonae.
The “peculiarly loud and somewhat musical sound” uttered by singing pool frogs was a common and distinctive sound for decades throughout the wetlands of east England. But everyone assumed this frog species had been introduced from mainland Europe — a common, albeit peculiar, pastime indulged in by Victorian naturalists — so no one really cared when it began to fall silent. By the late 1990s, it was too late: pool frogs had disappeared from Thompson Common, their final home in England.