Hook
A team working at Ghost Ranch, New Mexico has identified a crocodile relative that lived 210 million years ago. It had deeper jaws than modern crocodiles, reinforced skull bones, and teeth arranged for crushing rather than piercing.
How do you know what a 210-million-year-old animal ate when all you have is bone?
Jaw Mechanics
Bite force correlates with two measurements: jaw depth (from tooth row to bottom edge) and muscle attachment sites. Deeper jaws mean more room for muscle. More muscle means more force. You measure these features on the fossil, compare them to living animals with known bite forces, and estimate what the extinct animal could generate.
Tooth shape reveals feeding strategy. Conical teeth with sharp points are for piercing—a modern crocodile stabbing fish. Flattened teeth with broad surfaces are for crushing—a sea turtle breaking crab shells. Bladed teeth with serrated edges are for slicing—a carnivore shearing muscle. This crocodile relative had blunt, robust teeth that interlocked when the jaw closed.
Teeth don’t stay pristine. They chip, crack, flatten when they hit hard objects. Paleontologists examine fossil teeth under magnification for scratch patterns, fracture lines, pits. Teeth that crushed shells show different wear than teeth that tore soft tissue. This fossil’s teeth show blunt-force damage—the kind you see in animals that bit down on bone and shell, not the slicing wear of fish-eaters.
Scientists compare the fossil jaw to modern animals that crush prey. When every comparison points to the same feeding strategy, you have a functional hypothesis.
Inherited Constraints
The crocodile’s skull inherited its basic shape from earlier archosaurs. Natural selection modified it over millions of years. Individuals with slightly stronger jaws survived better when hunting prey with tough defenses. The ones that could crack shells ate more, lived longer, reproduced more. The trait spread.
Evolution modifies what’s already there—it doesn’t build from scratch. This crocodile’s crushing jaws emerged because the standard archosaur skull could be pushed in that direction under selective pressure. The constraints matter as much as the outcomes. Many different lineages converge on similar crushing adaptations because the physics of breaking hard objects stays constant whether you’re a mammal, a reptile, or a fish. Deep jaws, robust teeth, reinforced skull bones appear again and again because they solve the same mechanical problem.
Each fossil shows a body plan that survived long enough to reproduce, in a specific environment, facing specific challenges. When you see the same solution in unrelated lineages—crushing jaws in ancient crocodile relatives, modern sea turtles, certain extinct marine reptiles—you’re watching convergent evolution. Different starting points, same endpoint, because the problem was the same.
What Bones Cant Tell
Soft tissue usually doesn’t fossilize. Behavior that leaves no skeletal signature is invisible. Did this crocodile relative hunt in packs or alone? Was it territorial? Did it care for its young? The skeleton is silent.
Paleontologists build confidence through multiple lines of evidence. Jaw structure tells you the animal could crush hard prey—it had the hardware. Tooth wear tells you it did crush something hard—the damage is there. Prey fossils found in the same formation tell you what was available. Comparison to living relatives—modern crocodilians, birds (the other living archosaur lineage)—tells you what behaviors are plausible given the body plan.
You can’t run an experiment on a 210-million-year-old animal. But you can constrain inference with physical law. Jaw mechanics follow the same physics today as they did in the Triassic. Tooth wear follows the same material science. The fossil records forces applied over a lifetime—millions of bites, steps, struggles.
When five independent lines of evidence point to “this animal crushed hard-shelled prey,” confidence rises. When a sixth fossil shows up with the same features and wear patterns, it rises again.
Close
Every structure in a living animal—or a 210-million-year-old fossil—is the outcome of generations solving problems. The method that reveals this is comparing form, function, and context.