Get a Britannica Premium subscription and gain access to exclusive content.įossil evidence supporting the prediction of grasping arms and slashing foot claws was borne out by the discovery in the 1970s of a Velociraptor preserved in a death position with a small ceratopsian dinosaur, Protoceratops. The relatively large brains of dromaeosaurs enabled them to carry out these complex movements with a degree of coordination unusual among reptiles but quite expected in these closest relatives of birds. In doing so, dromaeosaurs may have been able to hold this one-footed pose by using the rigidly outstretched tail as a counterbalance, or they may have attacked by using both feet in a single leaping action. The tails of dromaeosaurs were also unusually long and were somewhat stiffened by bundles of slim bony rods that were extensions of the arches of the tail vertebrae.ĭromaeosaurs apparently ran down their prey (probably small- to medium-sized herbivores), seizing it with the front claws while delivering slashing kicks from one of the taloned hind legs. This evidently helped them seize their prey in birds the same motion produces the flight stroke. Like troodontids and birds, dromaeosaurs had a unique wrist joint that allowed the hands to flex sideways. The largest killing claw belonged to Deinonychus and measured up to 13 cm (5 inches) in length.ĭromaeosaurs had large heads equipped with many sharp serrated teeth, and their long arms ended in slender three-clawed hands that were used for grasping. Instead, it was always held off the ground because it was much larger and was jointed differently from the other claws. Agile, lightly built, and fast-running, these theropods were among the most effective predators of their time.Īll dromaeosaurs were bipedal, and the second toe of each foot was extremely flexible and bore a specialized killing claw, or talon, that was not used in walking. Britannica Explains In these videos, Britannica explains a variety of topics and answers frequently asked questions.ĭromaeosaur, (family Dromaeosauridae), any of a group of small to medium-sized carnivorous dinosaurs that flourished in Asia and North America during the Cretaceous Period (145.5 million to 65.5 million years ago).This Time in History In these videos, find out what happened this month (or any month!) in history.
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