Before the 1990s, the loud chattering call of the northern pool frog could be heard across the wetlands of East England. But when it began to grow silent, no one really paid much attention - mainly because it had long been assumed that the frog (Pelophylax lessonae) was a species introduced from mainland Europe during Victorian times rather than a native - and therefore deemed to be of little conservation interest.
But when a raft of scientists in different disciplines actually began to investigate the frog, they discovered it to be a long-time native, right down to finding its bones along with those of Saxon-era humans from over a thousand years ago. Unfortunately, just as this realisation came to light, the northern pool frog croaked in England for the very last time in its last remaining hold-out in the wetlands of Norfolk. With habitat loss as a primary cause, the northern pool frog was declared extinct in England in 1995.