"Happy as a clam" is one of those expressions that makes you wonder: Does this phrase come from an actual measurement of the happiness of clams?
Unfortunately, no. It doesn’t seem that anyone has ever attempted to measure clams' moods. The phrase most likely started as the longer phrase “happy as a clam at high tide,” and was popularized in the early 19th century, particularly in the northeastern United States. Clams can only be readily dug up by humans when the tide is low; in high water, they’re almost impossible to find. Therefore, at high tide, clams are (theoretically) very happy that they won’t be dug up for some beachgoer’s meal.
Although this association conjures up ideas of safety and security, the modern saying is more about pure happiness than freedom from danger. Of course, most people today don’t run much risk of being eaten by bigger creatures, but next time someone tells you that they’re “happy as a clam,” try not to remind them about low tide.
Erica Hersh is a graduate student in Health Communication at Tufts University. She's part of our College Weekend extravaganza.