You just need to glance at a 150-million-year-old fossilised Archaeopteryx to see that birds’ ancestors were not toothless. And yet bird teeth are now as rare as proverbial hens’ teeth.
Why don't birds have teeth?
So what exactly happened between then and now? Biologists aren’t quite sure. What they do know is that, about 100 million years ago, genetic mutations emerged that prevent tooth development by blocking enamel and dentine production.
These can be reactivated artificially to induce chicken embryos to produce peg-like reptilian teeth. More mysterious is why they lost them. One possibility is that replacing teeth with a horny beak reduces the payload, making flight more efficient. Beaks are certainly highly versatile tools that can be wielded to sip nectar from flowers, tear flesh from bones, crack nuts, filter food from water and pluck insects from the air.
Compared to teeth, though, they are less useful for chewing and grinding food. The gizzard, a muscular section of the gut often filled with swallowed stones, can help there, but sometimes, only teeth – or something very like them – will do.
Do any birds have teeth?
Sawbill ducks such as goosanders and mergansers have developed tooth-like serrations along the edge of their bills to help them hold onto their slippery fish prey.
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