How much do imperial penguins weigh?

The mass of an imperial penguin varies based on the time of year and the individual penguin's age and health. During the breeding season, an average imperial penguin weighs around 30-35 kilograms (66-77 pounds). When leaving their breeding grounds, adults may weigh as little as 23 kilograms (51 pounds). At the end of their molt around January and February, some penguins, especially males, may weigh as little as 11 kilograms (24 pounds).