I didn’t know about the grain or rabbit tests. At least the rabbits got off the hook when the frogs presented themselves as a better option, I suppose.

So sensitive in fact that a really common type of pregnancy test basically involved exposing a particular type of frog to human female urine. The frog being so sensitive to the presence of certain hormones would begin to ovulate if the urine sample was from a pregnant woman.

Really interesting but a bit of a shit lot in life for the frog!