Physiology: Animal Function and Reproduction

Reproduction

Which birds lay the largest and smallest eggs?

The elephant bird (Aepyornis maximus), an extinct flightless bird of Madagascar also known as the giant bird or roc, laid the largest known bird eggs. Some of these eggs measured as much as 13.5 inches (34 centimeters) in length and 9.5 inches (24 centimeters) in diameter. The largest egg produced by any living bird is that of the North African ostrich (Struthio camelus). The average size is 6 to 8 inches (15–20.5 centimeters) in length and 4 to 6 inches (5–15 centimeters) in diameter. The smallest mature egg, measuring less than 0.39 inch (1 centimeter) in length, is that of the vervain hummingbird (Mellisuga minima) of Jamaica. Obviously, the larger the bird, the larger the egg. But when compared with the bird’s body size, the ostrich egg is one of the smallest eggs, while the hummingbird’s egg is one of the largest. The Kiwi bird of New Zealand lays the largest egg relative to body size of any living bird, with an egg that weighs up to 1 pound (0.5 kilograms).