The mystery of egg shape goes back to Aristotle’s theory which states that the long and pointed eggs indicate that the egg will hatch a female bird while those that are rounded are male birds. The theory has baffled biologists and mathematicians for centuries, but another study published recently in the journal of science concludes that egg shape is much determined by the time a bird spends in flying.
Biologists have spent years hypothesizing how eggs get different shapes from round to pointed shapes. For instance, the owl eggs are usually more round while the eggs of a hummingbird look tinier like Tic Tacs and others are pointed at one end. The recent report shows that the theory could be much determined by the flight ability of birds.
According to a team of scientists from Princeton University led by Mary Caswell Stoddard, birds that nests on cliffs lay eggs that are cone-shaped. Chickens lay eggs that are oval-shaped and long-distance good fliers tend to lay asymmetric or elliptical eggs. The penguins which fly in the water normally have elongated eggs. Based on Stoddard, birds that migrate for long trips need a body that sleeker and streamlined hence less space for interior cargo.
Furthermore, as the time goes by, the bird’s abdominal cavity and internal organs become smaller and compressed thus affecting the shape of the eggs. The researchers also found that birds that spend time flying out a lot such as the barn swallows, usually lay pointed eggs and birds that fly less such as the chicken, ducks will normally lay eggs that are rounded and symmetric.
Stoddard collaborated with a diverse team of researchers from different fields including the mathematics, physics, biology, and computer science to carry out the complex analysis. Another scientist, Charles Deeming an ecologist from the University of Lincoln who was not part of the study state that the body structure of bird determines the shape of the eggs. There could be a direct link between the anatomy of the bird and egg shape. The recent theory could be a solution to the controversy surrounding egg shape that has existed for centuries.