Birds are one of the most diverse groups of animals on Earth, with over 10,000 living species identified. Most living birds have beaks, but some ancient birds possessed teeth. So are there any toothed birds left today? The short answer is no, there are no living birds with teeth. All living birds have beaks made of keratin instead of enamel-capped teeth. However, there are a few rare examples of modern birds with tooth-like serrations on their beaks.
When did toothed birds exist?
Birds evolved from feathered theropod dinosaurs during the Jurassic Period, around 150 million years ago. Some of their dinosaur ancestors, like Velociraptor and Archaeopteryx, had teeth. The earliest known birds like Archaeopteryx retained these dinosaurian teeth. Toothed birds were common during the Mesozoic Era, which lasted from about 252 to 66 million years ago. But by the time the Cretaceous-Paleogene extinction event occurred around 66 million years ago, only a few toothed bird lineages remained.
During the diversification of modern birds, tooth loss occurred independently in several evolutionary lineages. The last toothed bird went extinct around 68 million years ago. Since then, all living birds have been toothless. The causes of tooth loss in early birds are not fully understood but may be related to changes in diet or feeding behaviors. For example, the emergence of powerful musculature in the jaw allowed beaks to take over tasks previously carried out by teeth.
Examples of early toothed birds
Some notable examples of extinct toothed birds include:
- Hesperornis: Lived 70-80 million years ago during the Late Cretaceous. Had teeth and jaws adapted for catching fish.
- Ichthyornis: Another toothed diving bird from the Late Cretaceous, about 86 million years ago.
- Vegavis: A duck-like bird with teeth that lived 66-68 million years ago.
- Sapeornis: One of the earliest toothless birds from 120 million years ago.
These Mesozoic birds had true teeth with enamel and dentine capped in enamel. Their teeth were set in sockets in the upper and lower jaw bones (alveolar sockets). The teeth were recurved and pointed to snag slippery prey like fish.
Bird skulls with and without teeth
The skulls and jaws of ancient toothed birds were similar to their dinosaur ancestors. This is in contrast to modern toothless birds which have beaks and jaw structures very distinct from dinosaurs.
Toothed birds had:
- Teeth set in sockets in both jaws
- Longer, narrower jaws
- More teeth further back in the jaws
- Wide openings in the jaw bones (fenestrae)
Modern toothless birds have:
- Beaks with a horny covering
- Shorter, broader jaws
- No teeth or alveolar sockets
- Smaller or absent fenestrae
This transition in jaw and beak structure reflects an adaptation over millions of years from capturing prey with teeth to new feeding strategies like stabbing, crushing, and grasping food items.
Advantages of beaks over teeth
While teeth are useful for grabbing, piercing, and chewing food items, beaks have their own evolutionary advantages:
- Beaks are lighter than teeth and jaws, an asset for flight.
- They can be shaped in an infinite variety of forms adapted to specialized feeding niches.
- The keratin coating is resilient and continuously growing.
- Beaks do not require an energy-intensive process of tooth replacement like teeth do.
- They allow birds to exploit food sources like seeds that would damage teeth.
The tremendous diversification of beak shape, size, and function contributed to the success of modern birds. Beaks enabled innovative feeding strategies and allowed birds to radiate into a vast array of ecological niches.
Rare examples of modern birds with tooth-like structures
While no living birds have true teeth, a couple of examples have evolved tooth-like structures:
- The extinct moa birds of New Zealand had pseudoteeth – structures with form but not composition of true teeth.
- Several duck species have tooth-like serrations on the cutting edges of their beaks to help grip slippery food items.
- Some juvenile ostriches have projection that look like teeth, but are lost before adulthood.
- Fossil evidence indicates some early penguins may have had tooth-like projections on their beaks.
However, these pseudoteeth are just hardened extensions of the rhamphotheca, the keratin casing on the beaks. Unlike true teeth, they are not made of enamel and dentine or set in bony sockets. They are simply structural projections, albeit sharp tooth-like ones in some cases. Nonetheless, these serrated beaks allow certain birds to hold onto wriggling prey like fish, much like their toothed ancestors did.
Conclusion
In summary, there are no living birds that possess true teeth like those found in ancient birds and dinosaurs. Beaks replaced teeth around 68 million years ago in ancestral birds and have been passed down to all 10,000-plus living species. With lightweight yet strong and versatile beaks, modern birds have diversified to fill a wide range of niches across the planet. So while beaks prevailed over toothed jaws, a few examples of tooth-like projections on some modern bird beaks remain as a relic of their toothed ancestry.
