Insights about the possible hunting and killing methods of the- ropods spring from a variety of studies. Some paleontologists, including Emily Rayfield and Greg Erickson, have studied the bite and stress forces of theropods using computed tomography and scale models to understand the skull mechanics of biting. Others, including theropod expert Thomas Holtz, have drawn on an under- standing of the whole animal, synthesizing anatomical knowledge
to enable it to function in its ecological niche. Humans are by no means “better” than other animals because they have bigger brains. Humans are better at reasoning and abstract thought but are not better at, for example, doing what elephants do, or what voles or owls do. The brains of those creatures are adapted for doing what they do. It is not a matter of “better” or “worse.”
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about theropod jaws, teeth, sensory acuity, locomotion, and weap- onry with observations of extant predators. Holtz has suggested three categories of killing strategies that may have been used by theropods.
Grapple- and- slash predators. These predators usually wait in
hiding to ambush their prey and then use their forelimbs to seize prey after a very short chase. They kill their prey with a combina- tion of grappling claws on the forelimb, bites, and bruising kicks from the hind limbs. Prey may be suffocated by a bite that covers the nose or that holds the prey’s mouth shut, or the predator may clamp down on the throat and crush the trachea (windpipe). Among extant carnivores, large cats such as tigers and cheetahs are grapple- and- slash predators.
Dromaeosaurs used an even more specialized version of the grapple- and- slash technique. Equipped with a large “sickle” claw on the second toe of each foot, dromaeosaurs had proportionately shorter legs than other theropods, so it is likely that dromaeosaurs did not chase their prey for long. Their long arms and hands— with three long, clawed fingers and a flexible wrist— gave them the abil- ity to grasp a prey animal firmly. The toe claw retracted up out of the way when the animal walked but could be flipped down, like an open switchblade knife, when the dromaeosaur was on the attack. Such an arsenal leaves little to the imagination.
One of the larger dromaeosaurs was Deinonychus, named “ter- rible claw” after its formidable foot claw. Everything about its anatomy suggests that this dromaeosaur was an energetic, swift- running animal. After closing in on its prey, Deinonychus probably launched its attack by leaping at the victim feet first, with toe claws extended, gaining a foothold on the prey, and puncturing it with its claws. Thus would the bloodbath begin; the prey, weakened considerably, soon would be unable to struggle. Using its forelimbs to hold the prey, Deinonychus could finish it off by biting and con- tinuing to inflict puncture wounds with its feet. One spectacular fossil from Mongolia provides proof of such grapple- and- slash
a death grip with the herbivorous Protoceratops (Late Cretaceous, Mongolia), an early horned dinosaur. The theropod is positioned in the way that paleontologists would expect to find in a grapple- and-slash attacker, with its feet kicking the underbelly of the small prey.
Grapple-and-bite predators. These predators are also ambushers
and use their claws to hold the prey while the jaws do the killing. Hawks, eagles, and other modern birds of prey (which are correctly called “raptors”) use this technique. Large theropods other than the short-armed Tyrannosaurus were probably of the grapple-and-bite variety. These large theropods included such giants as Allosaurus,
Spinosaurus, Giganotosaurus, and Carcharodontosaurus. The claws
were used to bring down the prey, but the primary killing weapon was the teeth. Unlike the bananalike teeth of tyrannosaurs, the teeth in these other predators were narrow and bladelike. They were excellent for slicing chunks of flesh from their victims.
Pursuit-and-bite predators. This type of predator brings down
its prey with its jaws after a fairly long chase and then completes the kill using a combination of biting and suffocation. Modern wolves, other dogs, and hyenas use this technique. The claws are mostly used to hold down the prey animal rather than to slash it. Tyrannosaurs probably used this method, taking advantage of their long legs, huge raptorial feet, muscular necks, and jaws lined with sturdy, bone-crunching teeth. Tyrannosaurs probably fed by clamp- ing down on the body of the prey with their jaws, then pulling and twisting with their enormous strength to severely damage bones, muscles, and internal organs and, if possible, rip chunks of meat and bone from the prey.
No matter which technique the predator used, attacking a large herbivore had its risks. If the herbivore was protected with weap- onry, such as horns or a sturdy tail club, the theropod might risk its life by challenging a healthy adult. The huge weight and strength of the largest sauropods and hadrosaurs could be used to deflect or
injure a pursuing predator. Although theropods were surefooted, their anatomy did not allow them to step to the side; this made them vulnerable to the sideways swipe of a plant eater’s heavy tail. These tails may have weighed between 1,000 and 3,000 pounds (450 and 1,360 kg), depending on the kind of plant eater. A blow from such a tail could knock even the largest theropod over, perhaps injuring it severely, while the plant eater made its getaway. For this reason, it is safe to assume that predatory dinosaurs, like most liv- ing predators, may often have chosen young or infirm individuals as prey.