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Name means: Terrible Claw


Species: antirrhopus

Range: Early Cretaceous (Albian, 112-109 MYA) from Montana, Utah, Wyoming, Oklahoma

Size estimate: 10-11 ft length, 160-220 lbs

Discovery: John Ostrom, 1969

Classification: dinosauria, saurischia, therapoda, maniraptora, dromeosauridae


Fossil evidence inspired this attack scene. Since these two species’ fossils often occur together, it could mean that Deinonychus preferred Tenontosaurus over other prey. Some scientists have noted that single Tenontosaurus skeletons show evidence of feeding or attack by different Deinonychus individuals. They argue that this shows Deinonychus hunted in packs. Others counter that bite marks can happen at different times. One animal could make the kill, eat its fill, then others scavenge the carcass later. A third possibility suggests that different animals, drawn by the cries of a frightened Tenontosaurus, might gather like a flash mob. They would help each other make the kill, but go their separate ways afterward. The evidence at this time remains unclear.


These sculptures represent the “Dinosaur Renaissance” view of Deinonychus. They might look more accurate than the Deinonychus statues across the river, but discoveries from the past 20 years show they still fall short of portraying the original animal. For one thing, their heads looked different on the living animal. Because of their light build, Deinonychus skulls do not preserve well. Scientists must reconstruct them based on related animals. These statues use Velociraptor as a head model. However, new finds now show that Deinonychus skulls had a deeper profile than the thin Velociraptor snout.

Though this scene shows Deinonychus using its famous “killing claw” as a slashing weapon, recent theories cast doubt on that idea. New reconstructions of raptor claws give them a rounder cross section not suited for slashing. Some contend that Deinonychus really used that claw  to grip and climb up larger prey. Others argue that feathers on the animal’s arms suggest a more birdlike attack pattern. Like some modern birds of prey, perhaps Deinonychus and other raptors killed prey with their feet. Flapping their arms for balance and leverage, they would drive the claw through blood vessels in a sort of death grip. More evidence and experiments may give us a clearer picture of raptor attack habits in the future.


Refer to the Deinonychus sign across the river for more information on this animal.

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