The blood cockles (genus Telligarca) are unusual among molluscs in having evolved to use the same hemoglobin oxygen-carrying group that we have in our blood. This gives their flesh a red color and allows them to thrive in low oxygen environments. They can even breathe air for a limited time! Unfortunately, because these low O2 environments can also be a sign of sewage pollution, eating blood cockles can be very risky, as they will readily take up hepatitis and other pathogens. #clamfacts