Try to Guess Which Came First, the Chicken or the Egg?
- VIVA/Nur Faishal
These eggs had extremely thin outer shells, only about 100 microns thick, "That's the thickness of a human hair," Stein said.
However, based on their structure, these early dinosaur eggs would have been rigid, like porcelain, rather than flexible, like a banana peel, making them the earliest known example of an egg as we know it today.
That thinness probably explains why researchers have had trouble finding earlier examples of eggshells. When an egg encounters rich, acidic soil, it begins to slowly dissolve.
"The soil would have made it impossible for such a thin calcareous layer to be preserved," Stein said.
Another idea is that early dinosaur eggs were soft-shelled, and so didn't preserve well in the fossil record, according to a 2020 study published in the journal Nature. So, the egg predated the chicken. Well, if we're talking about the first chicken egg, the story changes.
Chickens (Gallus gallus domesticus) likely evolved from a subspecies of red jungle fowl (Gallus gallus) around 50 million years ago. Humans living in Southeast Asia first domesticated these birds somewhere between 1650 B.C. and 1250 B.C., according to a 2022 research article published in the journal Proceedings of the National Academy of Sciences.
At some stage during this domestication process, the last ancestor of the modern chicken would lay an egg containing an embryo with enough genetic differences to make it distinct from its parent species.
This embryonic chicken would develop in the non-chicken eggs before hatching. Upon reaching adulthood, this chicken ancestor would lay the first chicken egg. By this route, chickens can be said to predate the egg.
The reason is, in the article 'Origin and History of the Chicken' published on the University of Wisconsin-Madison website, there is evidence of chickens interbreeding with other subspecies of forest fowl. This happened even after chickens became their own genetically distinct subspecies. Some of these traits are seen in certain modern chicken breeds.
