A great white shark is a masterwork of evolutionary engineering. These beautiful predators glide effortlessly through the water, each slow, deliberate sweep of the powerful tail driving a body specialized for stealth, speed, and efficiency. From above, its dark back blends into the deep blue water, while from below its pale belly disappears into the sunlit surface.
In an instant, the calm glide explodes into an attack, accelerating to more than 60 kilometers per hour, the sleek torpedo-like form cutting through the water with little resistance. Then its most iconic feature is revealed: rows of razor-sharp teeth, expertly honed for a life at the top of the food chain.
Scientists have long been fascinated by great white shark teeth. Fossilized specimens have been collected for centuries, and the broad serrated tooth structure is easily recognizable in the jaws and bite marks of contemporary sharks.
But until now, surprisingly little was known about one of the most fascinating aspects of these immaculately shaped structures: how they change across the jaw and to match the changing demands throughout the animal’s lifetime. Our new research, published in Ecology and Evolution, set out to answer this.
From needle-like teeth to serrated blades
Different shark species have evolved teeth to suit their dietary needs, such as needle-like teeth for grasping slippery squid; broad, flattened molars for crushing shellfish; and serrated blades for slicing flesh and marine mammal blubber.
Shark teeth are also disposable — they are constantly replaced throughout their lives, like a conveyor belt pushing a new tooth forward roughly every few weeks.
Great white sharks are best known for their large, triangular, serrated teeth, which are ideal for capturing and eating marine mammals like seals, dolphins, and whales. But most juveniles don’t start life hunting seals. In fact, they feed mostly on fish and squid, and don’t usually start incorporating mammals into their diet until they are roughly 3 meters long.
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