Freaky Frogs: African Clawed Frog

From the 1930s through to the 1960s, a small aquatic frog was used as a biological pregnancy test. This may sound suspiciously like one of those medieval folk remedies – in the same vein of shaving the rear end of a live chicken and holding it under your armpit to cure the plague – but this frog really could tell if you were pregnant or not.