...Both species of decapods showed no seasonal differences in chela muscle performance. Their ability to function over wide ranges of temperatures is undoubtly essential in their successful latitudinal distribution. The difference in the capacity of these two species to rapidly acclimate to cold temperatures is reflected in their natural habitats. C. sapidus lives in estuaries where large short term temperature fluctuations are common. M. mercenaria, a marine coastal subtidal dweller, lives where temperature fluctuations are smaller.