Wet Behind the Ears

Etymology:

• The new born baby is wet allover with fluid. The body of the baby quickly starts to dry but the indentation behind the ears stay wet for a long period of time. The expression originated from the American armed forces in the 20th century when they used this phrase to refer to newly admitted soldiers. The phrase is also used for young animals washed the mother. Farmers have known this fact about the baby for many years.