The tiny, pale surf clam about the size of a fingernail that most people have seen and collected on beaches around the world holds clues in its shell to Earth's past. For the first time, researchers have been able to identify the monthly, and even weekly, ocean temperatures recorded in these smooth clam shells. Because ancient civilizations consumed these ubiquitous clams and left the shells at archeological sites, researchers now have a new way to reconstruct climate and its fluctuations from nearly 3,000 years ago.

Source: Climate change record in clam shells