PAchycephalosaurus
Pachycephalosaurus was a large, bipedal dinosaur known for its extremely thick, bony skull dome, reaching up to 4.5 meters long. It lived in western North America during the late Cretaceous period (70 to 65 million years ago). These bipedal herbivores were often found in subtropical and forested floodplains with abundant flowers. Pachycephalosaurus mainly grouped with its mate or blood kin, with one alpha male leading a harem of females, which will comprise over 50% of the herd limit, and 25% of the herd will be lesser males, and another 25% will be children. The herd limit is 12.
Tier: 2
Dimorphism: Males have brighter coloring and have rounder skulls. Females have dull coloring and flatter skulls
Habitat: Can be found nesting anywhere in Riparia.
Diet: Herbivore/Omnivore
Active Time: Diurnal, active during the day, while sleeping during the night.
Group size: 8 individuals
Defense: 5 individuals
Nesting Season: Spring and summer
Offspring: Up to 5
Adoption: ✅
Behavior
Pachycephalosaurus is territorial and very protective of its herd. If a carnivore gets too close to the herd (4 to 6 body lengths depending on group size), they may threat call three times before the males (4 males, including the alpha male) attack the carnivore till it backs off or dies. Pachys were often vocal with pack members between loving calls (heart call) or rubbing up against each other. A solo Pachycephalosaurus is very aggressive and needs its personal space, which it may threat call any T1 through T3 carnivore or herbivore 2 times (2 body lengths away from the Pachy) if these threat calls aren’t heeded, they will attack and leave it wounded and beaten (death scars) if the dinosaur doesn’t stop, then it will kill this dinosaur without remorse. Young male Pachycephalosaurus would spar with each other for practice in the herd to compete later on in life for alpha.
Mandatory Traits
Follow the leader
One male of the group, who the herd deems worthy of alpha, gets to lead the herd. Any Pachy that strays away for too long (3 minutes) isn’t welcome back into the pack and must fight its way back in by winning a sparring match. Both adult males and females will participate in this.
Rightful Leader
Other adult males in the pack must spar with the alpha male of the group for the role of pack leader. If the original alpha wins every spar, it keeps its role as alpha for as long as it lives.
Hard-headed
Pachycephalosaurus, if caught alone, will not back down from a fight if being hunted unless it’s outnumbered or has fear factor (T4-5).
You Look Trustworthy
Solo Pachycephalosauruses will go up to any T4-5 herbivore-friendly calling it and try to group with it. If they are met with a friendly call in return, they will go get a preferred food of that herbivore and become its flamekin, but if met with aggression, they will hit the tail of the dinosaur for rudeness and run off broadcasting to annoy the herbivore till out of LOS.
Optional traits
Fun & Games
Young (juvenile stage of growth) Pachycephalosaurus may fake charge the females of the group for fun. If the female doesn’t like the youngling’s behavior, they may headbutt the baby once to correct its behavior. If it keeps going back at it, the juvenile Pachy could end up meeting its end.
Learning & Preparing
Adolescent Pachys learned from their past mistakes and learned to respect their herd’s older females, and now only play with each other. They also end up sparing at times for practice.
Credit: Spook
Last updated: 10/22/25
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