'Which came first – the chicken or the egg?' is a riddle that's bamboozled young and old alike for generations. In fact, the Greek philosopher Plutarch discussed the question in an essay called Symposiacs in around 100AD. And even he was by no means the first to consider it.


It's a simple question. But if the egg came first, then who laid it? After all, eggs come from chickens. And if the chicken came first then where did it come from? Because chickens hatch from eggs. So which came first?

Well, you'll be relieved to learn that there is a clear answer as to which came first – and the answer lies in how animals evolved.

Mallard in flight.

So, which came first – the chicken or the egg?

It's pretty safe to say that the egg came first, because if there had been no egg, there would have been no chicken. Chickens are birds, and we know that birds evolved from reptiles, so we can say that the first bird hatched from an egg that was laid by a reptile that was very similar to, but not quite, a bird itself.

Archaeopteryx Lithographica Fossil
Archaeopteryx is often cited as the first bird to evolve from the dinosaurs. © Naturfoto Honal/Getty

Of course, this reptile also came from an egg, and, as we know reptiles evolved from amphibians, the very first reptile was, in turn, the offspring of an amphibian that was almost, but not quite, a reptile.


In fact, any animal that is multicellular and practises sex produces what are properly called eggs. Though their name means ‘first animal’, protozoans are not animals and don’t produce eggs. Exactly what the first true animal was is unknown. What we do know is that it lived around one billion years ago deep in the Precambrian – and it produced eggs.


Paul McGuinnessEditor of BBC Wildlife and discoverwildlife.com

Paul is the editor of BBC Wildlife and discoverwildlife.com. A highly experienced magazine journalist with over 25 years in publishing, Paul was previously editor of BBC History Revealed and BBC Knowledge.