Scientists are still trying to answer the age-old chicken-and-egg question (2024)

Scientists are still trying to answer the age-old chicken-and-egg question

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NPR's Don Gonyea talks to scientist Michael Benton about his new research and tries to answer the age-old question: What came first, the chicken or the egg?


It's a question that has been warping our brains for years. What came first: the chicken or the egg? A team of scientists from the University of Bristol in England believe they have cracked the code. One of these researchers is Michael Benton. He is a professor at the university's School of Earth Sciences and is now joining us. Welcome to the show.

MICHAEL BENTON: Thank you very much.

GONYEA: Mild apologies for the pun there. You've heard them all, I'm sure.

BENTON: Not at all.

GONYEA: We'd all like to know. Was it the chicken or the egg? What have you found?

BENTON: Yes, the quick answer is the egg, because the chicken is just one of many birds. And of course, as we know, all birds lay an egg with a hard shell. So if you're familiar with your breakfast egg, it's pretty much the same for all birds. And so it is probably the egg laid long ago by the very first bird. So a quick answer is that the egg comes first. However, our research shows that if you go deeper in time, this is actually not the whole story.

GONYEA: Okay. However, let's dive into the whole story. I mean, your first reaction was the egg, but then you said, wait a minute.


GONYEA: What is it, wait a minute?

BENTON: Many listeners may be aware that we know something about dinosaur eggs. There are many nests containing football-sized eggs. But a few years ago, some colleagues pointed out that the first dinosaurs most likely produced eggs with parchment shells. These are soft-shelled eggs. And the secret is something that has been known to lizard lovers for a long time, namely that many of them have the ability to keep the embryos inside. So the mother holds the cubs and releases them at a certain time. This is called extended embryo retention, EER. What we discovered is that the trait of long-term embryo retention goes all the way back to the beginning of reptiles. So it wasn't the hard-shelled egg. What they did was extended embryo retention.

GONYEA: So help me put this in the simplest terms possible. We know hard eggs. We even know eggs with a softer shell, which looks more like a membrane. But you're saying that these eggs weren't always there as part of birth or as part of protection….


GONYEA: ...of the embryo. So they have evolved too.

BENTON: So I think the easiest way to contrast that is that the standard textbook story is that the first reptile was wildly successful because it laid a hard-shelled egg, like a chicken egg, and it functioned as a private pond. This is a phrase people often used, a private pond, as opposed to the amphibians that were there before. We think of frogs and salamanders. They lay their eggs in water. They tend to leave them and the young grow up like little fish in the water. And then they finally leave. Therefore, amphibians must stay close to water. So the entire history of the evolution of life took place in the Carboniferous period, 300 million years ago. Some of the first reptiles gained this ability to escape from the water and conquer the entire landscape. Wrong. It wasn't the private pond. It was the prolonged embryo retention and live birth. It seems to be the primitive state of reptiles.

GONYEA: Why are these results important?

BENTON: I think it's important because the origins of reptiles and the later origins of dinosaurs, birds and mammals really changed the world. You know, we look across the landscape and everywhere you look you see birds and mammals. And you know, somehow it's not just us saying we're important. That is why we are aware of these beings.

GONYEA: Do you believe the old expression: which came first, the chicken or the egg? - do you want to leave? It feels like one of those things that lasts.

BENTON: No, I don't think so. It's a classic pub quiz question. So whether that is why the chicken crossed the road, I have no idea. But I expect people will continue to ask and answer it in different ways.

GONYEA: That was my next question, by the way (laughter).

BENTON: That's one, I can't answer it.

GONYEA: Okay. Michael Benton is a professor at the School of Earth Sciences at the University of Bristol. Thanks for joining us and explaining all this.

BENTON: Thank you very much.


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Scientists are still trying to answer the age-old chicken-and-egg question (2024)


What is the answer to the chicken and egg question? ›

What did you find? BENTON: Yeah, well, the quick answer is the egg, because the chicken is just one of many birds. And of course, all birds, as we well know, lay an egg with a hard shell. So if you're familiar with your breakfast egg, that's pretty much the same for all birds.

Has the chicken and egg problem been solved? ›

This just in: The scientists have solved it. After a millennium of taunting young biologists and philosophers as Plutarch pondered: “Which was first, the bird or the egg?” the great chicken and egg debate is perhaps coming to a close. The chicken (or, rather its amniote ancestor) has beat the egg.

What do scientists say about the chicken or the egg? ›

Dinosaurs laid eggs, the fish that first crawled out of the sea laid eggs, and the weird articulated monsters that swam in the warm shallow seas of the Cambrian Period 500 million years ago also laid eggs. They weren't chicken's eggs, but they were still eggs. So the egg definitely came first.

What is the scientific answer to which came first the chicken or the egg? ›

Back to our original question: with amniotic eggs showing up roughly 340 million or so years ago, and the first chickens evolving at around 58 thousand years ago at the earliest, it's a safe bet to say the egg came first. Eggs were around way before chickens even existed.

How old is the chicken or the egg question? ›

Even the specialised sort of eggs laid by birds, with their tough outer membrane, evolved more than 300 million years ago. As for chickens, they came into being much later. They are domesticated animals, so evolved as the result of humans purposefully selecting the least aggressive wild birds and letting them breed.

Did chickens evolve from dinosaurs? ›

Even though we don't have a complete fossil record, scientists are convinced that all birds are descended from dinosaurs. So just as humans are mammals, chickens are dinosaurs.

Has a chicken ever had twins? ›

Yes. It is a rare occurrence. When two chicks hatch from the same egg, the egg usually has two yolks. Usually, one embryo out competes the other and only one chick survives to hatch.

Has anyone ever bought egg and found a chicken? ›

It's unlikely, but not impossible. Most commercial egg farms have strictly all-female flocks because male chickens aren't needed for egg production and aren't suitable for meat either (chickens raised for meat are a different breed).

What is the meaning of the chicken and egg problem? ›

a situation in which it is impossible to say which of two things existed first and which caused the other one. Confusion, confusing and feeling confused.

Are chicken eggs like human eggs? ›

A human "egg" is an ovum, a single cell. A chicken egg, on the other hand, is complex structure constructed by the mother bird's reproductive tract in various stages. Most of the volume of a chicken egg is not the egg cell itself.

Are we eating chicken when we eat eggs? ›

Most eggs that people eat come from chicken, and chicken are poultry. That said, eggs are an animal byproduct—they're unfertilized eggs from the chicken. Think of them kind of like milk from cows. “So eggs themselves are not actually poultry,” Cording says.

What did the first chicken look like? ›

Charles Darwin proposed that chickens descended from the red jungle fowl—a colorful tropical bird in the pheasant family–because the two look so much alike. But proving him right has been difficult. Five varieties of jungle fowl range from India to northern China, and small chicken bones are rare in fossil sites.

What two birds made the chicken? ›

The modern biological approach revealed that a red junglefowl subspecies is the main wild ancestor of the domestic chicken. However, other red junglefowl subspecies and wild junglefowl species also contributed to the modern domestic chicken genetic profile.

Was the chicken born before 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.

Did scientists prove the chicken came first? ›

Dr Colin Freeman, from Sheffield University's Department of Engineering Materials: “It had long been suspected that the egg came first but now we have the scientific proof that shows that in fact the chicken came first.

Is there still an egg crisis? ›

Supply chain disruptions have further exacerbated the egg crisis. Complex supply chain structures and shortages of essential supplies and transportation have made it challenging for national egg producers to meet the growing demand, leading to price hikes and supply shortages.

Has egg production gone down? ›

There's an egg shortage because the ongoing bird flu outbreak reduced the number of egg-laying chickens. As of March 6, the virus has affected more than 82 million birds in the U.S. since January 2022, according to the Centers for Disease Control and Prevention. Most of the birds affected were egg-laying hens.

How did Paypal overcome the chicken or egg problem? ›

How did PayPal overcome the thorny chicken-or-egg problem? Paypal made the sign up process easier which attracted a good number of buyers. They then began giving out "free" money and used referrals to get people to sign up and use the app. Finally, they focused efforts on eBay, and encouraged users to pay with Paypal.

Did you know scientists finally concluded that the chicken came first not the egg because the protein which makes egg shells is only produced by hens? ›

Researchers found that the formation of egg shells relies on a protein found only in a chicken's ovaries. Therefore, an egg can exist only if it has been inside a chicken. The protein – called ovocledidin-17, or OC-17 – acts as a catalyst to speed up the development of the shell.

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