Dryosaurus altus

Coloration:
Adult and juvenile (both sexes) - A forest green color with a slightly darker green head, a yellow-green underbelly, and brown spots decorating the top of the body from the back of the neck to the tail.

Preferred habitat:
Abundant on Sorna, from Mountain Ranges to lowland areas. Dryosaurus can be found in dense and loose forests as well as more open areas.

Social structure:
Dryosaurus is often found together in loose feeding groups, sometimes close to larger herbivores. Each animal in the group take turns to out for danger while the others feed, although individuals tend not to interact with one another unless it is the breeding season.

Diet:
Low-growing plants; as well as fruits and leaves knocked loose by larger herbivores.

Description:
Small bipedal herbivore. Adults are strictly bipedal, however the juveniles are able to walk on all fours. Tail long and stiff, used for balance. Small, beaked jaws; shearing teeth hidden by fleshy cheeks; large eyes.

Behaviors:
Dryosaurus is an active and alert animal, and it is  among of the most common of dinosaur species on Isla Sorna. It has well-developed senses for detecting danger, and its large eyes enable it to see just in darkness just as well as daylight. This dinosaur is active both night and day.

Dryosaurus is preyed on by various small to medium-sized predators as  well as the juveniles of larger species, and thus it is at the bottom of the food chain. As a result it lives together in groups and can often be found alongside much larger herbivores such as hadrosaurs, benefiting from the safety their bigger contemporaries provide. Dryosaurus is very active and its groups are always on the move; often following in the wake of their larger bodyguards. When feeding, the sentries produce sounds similar to the calls of a juvenile crocodile or  alligator to  reassure those that have their heads buried in the undergrowth. Dryosaurus' warning cry sounds like the squeals of a distressed pig.

Dryosaurus has little defense against its predators other than to run, however a captured individual may lash out with its strong hind legs in an attempt to free itself. Dryosaurus is an adept runner, capable of running at speeds of up to 50 mph for considerable distances on its long hind legs, its body counterbalanced by its long stiff tail. It is also very agile, and can jump to reasonable heights. To protect the more vulnerable young, a healthy adult Dryosaurus may feign an injury in order to draw the attention of a predator away from the others, thereby allowing the young to escape with the rest of the group. When the predator falls for the ruse, the individual will show just how healthy it really is by jumping up and sprinting away, leaving its pursuer in the dust.

Even in spite of being a favorite prey of the majority of the island’s carnivorous population, Dryosaurus is a common herbivore due to its high birth and fast growth rates. During the breeding season, multiple feeding groups congregate together on forest edges, where the mating occurs. Males and females divide themselves into same-sex coalitions, and females take their time to browse the ranks of healthy males, who display to the females by inflating their expandable cheek pouches with air. When a male has attracted a female, he will try to keep her with him for as long as possible before she loses interest and wanders off, all the while viciously fending off rival males. The males fight one another by engaging in kicking battles, in which the males face one another, lean on one foot and then lash out with the other. These contests last but a few minutes in order to avoid serious injury from the animal’s powerful hind limbs.

The females typically lay their eggs in dirt and bury them with vegetation. Mothers fuss over their eggs nearly continuously, using their sensitive beaks to measure the nest temperature so that the eggs do not get cold or overheat. Unlike baby hadrosaurs, which are weak and confined to the nest, young Dryosaurus can leave the nest almost immediately after hatching, sticking close to the adults and being fed chewed-up plant material by their mothers. Unlike in a hadrosaur community, it is the females only which take care of the eggs and young - males typically ignore eggs and pay little heed to the juveniles of the group. The young grow quickly, and reach their full adult size in a matter of months. Out of all the young produced, half do not manage to reach adulthood.