Thermal and biochemical characteristics of the lipids of the leatherback turtleDermochelys coriacea: evidence of endothermy

Abstract
Unlike other sea turtles, the leatherbackDermochelys coriaceaforages widely in temperate waters during summer and dives to abyssal depths (>1000 m) where temperatures are low. There is strong anatomical plus limited physiological evidence in favour of at least facultative endothermy. The lipids of leatherbacks exhibit features which are consistent with maintenance of a core temperature above ambient levels when in cool waters. The lipid of flipper adipose tissue freezes at a lower temperature than lipids extracted from the blubber lining carapace and plastron. Lipid freezing points in leatherbacks are lower than for tropical caimans or terrestrial sheep, but higher than for lipids taken from the blubber of a grey seal. Leatherback adipose tissues show levels of unsaturation in neutral lipid fractions intermediate between those of seals and sheep.