Scientists Crack the Age-Old Debate: Chicken or Egg?

A team of scientists from the University of Bristol and Nanjing University may have finally answered the classic question: which came first, the chicken or the egg? Their research suggests early ancestors of chickens gave birth to live animals rather than laying eggs.

In their study, published in Nature Ecology & Evolution, the scientists examined 51 fossil species and 29 living species, categorizing them as either oviparous (egg-laying) or viviparous (live-birthing). The findings showed that early reptilian ancestors of chickens were viviparous. Professor Michael Benton explained, “When the amniotes came on the scene 320 million years ago… the amniotic egg was the key.” Professor Baoyu Jiang added that the study challenges the traditional view, revealing that “live-bearing lizards can flip back to laying eggs much more easily than had been assumed.”

The researchers propose that chickens’ ancestors initially gave birth to live young, suggesting the chicken came before the egg. This new theory could reshape our understanding of this age-old debate.