Scientists once thought that a male frog dubbed Romeo was the last of his kind. Then, when more Sehuencas water frogs were discovered in 2018, they hoped he would mate with a female they called Juliet. Sadly, their love story now is over—Romeo died (without offspring) last year.

The European brown frog is also known as the common frog, although its unique abilities make it anything but. Long before we had the luxury of storing milk in refrigerators, households in Russia and Finland had a more unconventional means of preservation ...