Figure 11 Changes in the concentrations in the blood plasma of glucose (top), non-esterified fatty acids (FA) and β-hydroxybutyrate (middle), and body temperature (bottom) in (a) male and (b) female breeding emperor penguins. The areas in yellow show natural habits, the start of the red striped area marks the end of the fast in the colony, and the red striped areas themselves show measurements during the period in which the penguins were penned, preventing them from returning to the sea and feeding (after day 115 in the males, and day 45 in females). The observation period began at the end of March and continued until the end of August (early in the Antarctic winter) for the males (a) and until the end of June for the females (b)