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This alligatorlike fish sucks—at lightning speeds

With a long, broad snout filled to the brim with flesh-piercing teeth, the alligator gar, a 3-meter-long freshwater fish, is easy to mistake for its reptilian namesake. What’s less obvious is that this toothy creature has been patrolling the bayous and rivers of North America virtually unchanged for tens of millions of years. Now, paleontologists have taken advantage of that long history to gain insights into how its ancient relatives might have snapped, sucked, and engulfed their food.

First, researchers used high-speed cameras to record 17 young alligator gar feeding in the lab and study the mechanics of their ferocious bite. The team also used x-ray scans of the fish’s head (above) to create a 3D model of its skull that was used to visualize the movements of the jaw bones during feeding.

The researchers assumed their study would be an open-and-shut case—the alligator gar was thought to capture prey simply by slamming its jaws shut. But they found something surprising: The gar also creates powerful suction at lightning speed (42 milliseconds) with tightly choreographed movements of bones in its skull and shoulder, according to research posted last week on the bioRxiv preprint server.

Those complex skull and jaw movements suggest a new feeding mechanism not only for the prehistoric-looking gar, but also its genuinely prehistoric relatives, scientists say. This can help fish biologists figure out how and what the modern gar eats—and paleontologists imagine how similar extinct species might have fed. What’s more, this deeper understanding of how a living fossil moves could help reconstruct similar motions in ancient species—and allow computers to reanimate actual fossil bones.