 For instance, when blubber is analyzed by direct carbohydrate measurements, it has been shown to contain as much as 8—30% carbohydrates.While postmortem glycogen levels are often depleted through the onset of rigor mortis, marine mammals have a much delayed onset of rigor mortis, even in warm conditions, presumably due to the high content of oxymyoglobin in the muscle that may permit aerobic metabolism to continue slowly for some time after the death of the animal.Additionally, in cold conditions, glycogen's depletion is halted at -18 °C (-0.4 °F) and lower temperatures in comminuted meat.