Lower critical temperatures of blue whales, Balaenoptera musculus

Kshatriya & Blake (1988, J. theor. Biol. 113, 479–498) estimates that the temperatures of cold Antarctic waters are below the thermoneutral limits of blue whales ( Balaenoptera musculus). As a consequence, they suggested that blue whales migrate from cold Antarctic seas to waters near the equator to minimize yearly energy expenditures. Here, we recalculate the lower critical temperatures of blue whales and find that they, like many smaller marine mammals, should not be obligated to increase their heat production in order to maintain homeothermy, even in sea water at its minimum temperature of about −2°C. Our results suggest that blue whales cannot conserve energy by migrating from cold to warm waters.