Deinonychus

Deinonychus is a dromeosaur originating from the Early Cretaceous of North America.

Characteristics
Deinonychus are lithe, wolf sized animals, covered in a heavy coating of blue feathers on their entire body except the start of the neck and the ankle down, and their hands. These feathers are fur-like except at the wings and at the fan formed near the tip of the tail, which are flight feathers. The scales on the face are a bluish-green, while the ones on their limbs are a more dull grey. When viewed from the dark, their eyes seemingly glow yellow. The arms and legs of Deinonychus are quite muscular and have very large claws, reaching up to 2 inches on the forelimbs. These claws adaptions are used for climbing, as Deinonychus are arboreal animals, and use this to travel safely from ground based predators.

They are also quite social animals, usually living in packs of 12 individuals. These packs have a hierarchy of alphas, betas, and omegas, which is determined by their hunting prowess with no distinction between the sexes' roles. Omegas will typically sit out conflicts in order to rear young at the pack's nesting sites, which are normally on the ground. although all members there will take shelter in the canopy when a larger carnivore comes by. When the rest of the pack hunts, they use a unique way to hunt prey: When prey is spotted, half the pack moves onto the ground to begin panicking and shepherding the prey animals, typically Stygimoloch and Hypsilophodonts, to where the rest of the pack that are still in the trees and can jump down on and kill the prey either by ripping them apart with their claws or biting their throats and suffocating them.

When threatened by larger carnivores such as Quetzalcoatlus whilst the pack is present, Deinonychus will go for an all out attack, leading to what Andrei Wynn describes as "Some of the wildest, bloodiest brawls I've ever seen". In spite of this, they will actively avoid both of the valley's apex predators, the Tyrannosaurus rex and Utahraptor.

The Arrival of Vulture Squad
Deinonychus were one of the dinosaur species released from the failing of the USSR Particle Collider inton Vulture Valley in Vietnam. A year later when Vulture Squad was camped pit in the valley while searching for a missing platoon of Green Beret, Xavier Wise was stalked by a pack of Deinonychus, but they quickly retreated when a Tyrannosaurus known as The Father approached the area on a trail back to his nest.

The next day, another pack of Deinonychus attacked a herd of Stygimoloch that Vulture Squad had been sneaking past. Realizing they were exposed to the animals leaping down from the trees, Xavier ordered the group to move into the herd in order to provide more targets for the dromeosaurs. While working initially, one of the Stygimoloch knocked over Eli Taylor, forcing the rest of the squad to rescue him before he was trampled to death. Now exposed, the pack moved away from the herd and any corpses they'd made and gave chase to Vulture Squad. After a chase across the river, the pack caught up to Vulture Squad as they were catching their breath. Taking the opportunity, part of the pack grabbed Eli and dragged him away from the Squad while another jumped Xavier when he lagged behind. With the help of Charlie Miller, both managed to kill the four Deinonychus attacking them. While this was happening, Logan Stovall was attacked by another Deinonychus, which he managed to mortally wound with a rock before performing a mercy shot on it. Just afterwards, Gerald Keyes found Logan and mentioned he had shot two more of the dinosaurs, but was attacked by the remainders of the pack and dragged away. After being dragged quite far, Gerald killed two of his assailants, and the remaining two retreated into the canopy when they sensed the presence of a nearby Utahraptor.

Trivia

 * Unlike in the books of the Primitive War series, the real Deinonychus is no longer believed to hunt in packs, based on studies of its growth and the ecological niches the juveniles are believed to have maintained.
 * In reality, adult Deinonychus is believed to have spent most of its time on the ground. Juvenile Deinonychus on the other hand, may have climbed trees to escape danger or to hunt Arboreal animals.
 * also In reality, they were also larger with adults growing up 11-12 feet long and weighting about 220 lb.