This old wives’ tale begins with the premise that eggs originate from chickens, and chickens come from eggs. For the most part, chickens have been around for just 10,000 years; eggs are only female reproductive cells that have developed more than one billion years ago. So, it seems that the puzzle is simple to solve… or is it?
By every reasonable standard, the egg predates the chicken. We tend to think of eggs as the shelled spheres placed by birds from which their babies hatch, unless we consume them first. However, eggs are laid by all organisms that reproduce sexually (the specialised female sex cells). That’s 99.99% of all eukaryotic life, which includes all animals, plants, and anything else save the smallest living forms that have cells with a nucleus.
The origin of sex is not known for definite, although it might have occurred up to 2 billion years ago and likely more than 1 billion years before. Even the hard-shelled eggs deposited by birds more than 300 million years ago are a result of evolution.
Chickens, on the other hand, were invented considerably later. A consequence of human selection of the least hostile wild birds, they have developed into domesticated animals. Somewhere between 10,000 and 15,000 years ago, this seems to have taken place.
The red junglefowl, a tropical bird still seen in the woods of Southeast Asia, is usually accepted as the chicken’s wild progenitor. Other junglefowl species may have contributed to the genetic mix. Humans have been transporting chickens throughout the globe for the last two millennia or more, and this is likely where the practise originated.
As a result, eggs precede chicks by a long shot. We should, however, take into account whether or not a chicken’s egg precedes a chicken in order to be fair to the riddle’s spirit. Because humans selectively bred only the most docile red junglefowls, the genetic make-up of the offspring will have changed. The red junglefowl (Gallus gallus) became a new subspecies, Gallus gallus domesticus, at some point in the domestication process.
A precise date and time cannot be determined in practise. However, in principle, two junglefowl mated, and their progeny was genetically distinct enough from its parents to be recognised as a chicken at some time. When it was fully mature, this chicken would have laid its first chicken egg, which would have come from an egg of a junglefowl. When seen in this light, the chicken takes precedence.
