Also known as "thick headed reptiles", Pachycephalosaurids are bipedal, fleet-footed herbivores that are well-known for their extremely thick skulls, which the animals use for display, defense against small predators, and most famously, for their use against other males in order to establish herd dominance and mating rights. In the case of Pachycephalosaurus, this involves aggressive head and/or body ramming, while the Homalocephale males engage in head-pushing contests.
There are two kinds of Pachycephalosaurid dinosaurs on the island, the small, timid Homalocephale and the larger, more aggressive Pachycephalosaurus.
Homalocephale calathocercos[]
Length: 9 ft (2.7 m)
Height: 3 ft (0.9 m)
Weight: 100 lb (45.4 kg)
These little dinosaurs are shy and reclusive, and are noteable for their flat, wedge-shaped skulls. Unlike Pachycephalosaurus, Homalocephale are generally unaggresive and will flee at the first sign of danger. They live in spread out feeding groups with designated sentries keeping an eye out for predators, and will occassionally forage alongside herds of Pachycephalosaurus - their larger, more aggressive relatives providing extra lookouts and protection.
The Homalocephale's preferred habitat is mountain slopes or hillsides. They feed on a wide variety of plant matter, and tend to forage for pine cones or other fruits that have fallen to the forest floor or which have been knocked lose by larger herbivores. During the breeding season, males endure pushing contests, where they butt against one anothers' heads and/ or bodies in tests of strength. They will develop short spikes at the back of their heads, which they use for show and intimidation.
Homalocephale calls include chirps, whistles, and long twitters.
Coloration and Sexual differences[]
Both sexes are a faded orange with blue-black striping. This pattern becomes smaller and more intricate atop the flat part of the head. Juveniles are a brighter orange, and the striping has more blue to it than in the adults.
Pachycephalosaurus wyomingensis[]
Length: 13 ft (4 m)
Height: 5 ft (1.5 m)
Weight: 1,000 lb (453.6 kg)
These tough Pachycephalosaurids are quite large and bulky, and are noteable for their tall, domed heads- their skulls are up to 30cm thick. Surrounding the dome and decorating the snout are bony knobs and short bony spikes, which are more pronounced in males than in females. Pachys are known for their aggressive, territorial nature, and when faced with danger, rather than running away they may try to defend themselves by facing the predator with lowered heads, snorting and stamping their feet. Although not so effective against large carnivores, such as Tyrannosaurs, charging at smaller predators such as raptors and Ornitholestes and ramming into their sides can potentially break bones and crush organs.
Males tend to be more aggressive than the females, especially during the breeding season. During this time, the aggression of the males explode and they will compete over each other for females. The spikes on the base of their domes will grow dramatically due to a surge of testosterone, and they will use these spikes to impress females and warn off less experienced males. Males that are equally matched may fight, using their domed skulls to batter each other into submission. The winner will then gain control of the females while the loser is usually evicted from the herd.
The Pachy's preferred habitat are mountain forests and scattered brush, where they feed on a wide variety of plant matter. They tend to live in small to medium-sized herds consisting of many females, their young, and a few subordinate males led by a single dominant bull who guards his herd fiercely. Sometimes, their herds also consist of their small relatives Homalocephale, and they can quite happily mingle with other large herbivores while grazing.
The Pachy's vocalizations include growls, bellows and snorts, and some kind of shriek, similar to a pig's squeal, produced when the animal is scared.
Coloration and Sexual differences[]
Both sexes have blue and brown mottling covering their bodies. Juveniles are the same. Male pachys are recognized for their longer, sharper spikes at the base of their domes, while females consist of blunt knobs. Infants of both sexes also have blunt knobs (males develop spikes as they age). Hatchlings lack the familiar dome of the adults- instead their skulls are flat similarly to a Homalocephale. Their skulls rise and thicken as they grow, eventually forming into the dome.
Named Pachycephalosaurids on Isla Sorna[]
Apollo
Genus: Pachycephalosaurus
Gender: Male
Info: Member of Hera's herd. He is constantly trying to establish his dominance over the herd and attempting to impress females Hera, Ekho and Pandora, and dislikes males Knob and Foglio. Unfortunately, both Foglio and Knob are larger and stronger than Apollo, therefore his status in the herd is low- especially after losing in a fight with Knob.
Ekho
Genus: Pachycephalosaurus
Gender: Female
Info: RP'ed by FeatherTail.
Foglio
Genus: Pachycephalosaurus
Gender: Male
Info: RP'ed by Tianchisaurus_nedegoapeferima.
Hera
Genus: Pachycephalosaurus
Gender: Female
Info: RP'ed by MissDNA. She is the alpha of the only roleplayed Pachycephalosaurus herd in LTL.
Pandora
Genus: Pachycephalosaurus
Gender: Female
Info: Member of Hera's herd. Mate of Knob.
Knob (deceased)
Genus: Pachycephalosaurus
Gender: Male
Info: RP'ed by dilorex.
Silvac
Genus: Homalocephale
Gender: Male
Info: Current leader of the Homalocephale flock. RPed by Tomozaurus.
Skodo (deceased)
Genus: Pachycephalosaurus
Gender: Male
Info: RP'ed by TheHunter.
Tholus (deceased)
Genus: Homalocephale
Gender: Male
Info: RP'ed by Deinonychus.