Can you tell the age of a penguin by the size of its beak?

No, you cannot determine the age of a penguin by the size of its beak alone. A penguin's beak is an important adaptation for survival, but it does not grow proportionately with age. In fact, some species of penguins undergo a beak color change as they mature. For example, Emperor penguins have a black beak as juveniles, which changes to a more orange color as they reach adulthood. Therefore, beak color may be a better indicator of age than beak size.

Overall, age determination in penguins requires careful examination of a variety of physical characteristics, such as plumage color, body size, and bone density, in addition to behavior and life history. Scientists also use techniques such as carbon dating and growth layer analysis of feathers to determine the age of penguins.