The Blanchard's Cricket Frog is so tiny it can fit on your thumb, and the distinctive call for which it is named would make it easy to hear — if it hadn't recently been declared locally extinct in its wetland habitat of southwestern Ontario. 

Thomas Hossie, assistant professor of biology who studies amphibians at the province's Trent University, described the sound as "shaking a bag of marbles." But the frog hasn't been seen (or heard) in decades.

The last confirmed sighting in Canada was in 1977…