Time Period - Barremian, Early Cretaceous
Length - 5-7 meters long (23 feet)
Height - 1.8 meters tall (6 ft)
Weight - 500-1000 kg (1,100lbs)
Diet - Hypercarnivorous
Having the unique distinction as one of the largest raptors that have ever lived, Utahraptor is a dinosaur that lived approximately 125 million years ago during the Cretaceous Period Utahraptor’s holotype specimen is fragmentary. It only had skull fragments, claws, a tibia as well as some caudal (tail) vertebrae. Phylogenetic evidence suggested that they had feathers. Their bones were hollow, but strong. They had robust short legs that were primarily made for strength rather than speed. The first Remains of this huge raptor species was found in 1975 by Jim Jensen and colleagues, however it wasn't until 1991 that they were studied properly. In 1993 the genus was created with a specific name honoring Chris mays , Who founded Dinamation, a company that created animatronic dinosaurs and the eminent American paleontologist John Ostrom.
A group of fossils from a smaller relative of Utahraptor known as Deinonychus was preserved with the body of a Tenontosaurus , This type of collective burial may indicate that dromeasaurs hunted in packs. Another seperate discovery in 2015 adds some backing to the claim ; a 9 ton block of sandstone from eastern Utah was found to contain the bones of 6 Utahraptors which appear to have all drowned together in quicksand , possibly all in collective pursuit of a potential meal.
Behavior/Territory
When it comes to dromaeosaurids, Utahraptor is about as nasty as they get. The largest yet discovered, and the largest on the island as well, no other dromaeosaurid can match up to the Utahraptor's size. Ideally Utahraptor would be the apex predator it was in its natural environment, were it not for the fact that it is a giant in a land of bigger giants. Although Utahraptor easily dominates the lower half of the predator guild that creatures like Austroraptor, Velociraptor, and Herrerasaurus form, it ends up having the tables turned on itself when confronted by multi-ton predators such as Allosaurus, Tyrannosaurus, and Carnotaurus. Utahraptor is a prime example of the middle link of the food chain.
Most common in forested areas, Utahraptor relies on having good cover always nearby in order to evade predators, and more importantly, to hunt. A cunning ambush predator, although it is able to keep a slow run for a long time, it prefers to utilize its ability to go into a great burst of speed from a crouched position to catch quick prey items. Once prey is caught, it is easily dispatched via RPR, where the predator pins the hapless victim under its immense weight and toe claws. In this case “dispatched” does not necessarily mean dead, commonly prey is eaten alive, as soon as it is pinned down.
Utahraptors are versatile in social structure, and function well in solitary and pack based life-styles. While a lone Utah is already enough of a threat for the island's smaller animals, a coordinated pack can corner the fastest prey animals and even take down some larger ones.
Because they require such specific environments and prey types to successfully survive, most Utahraptor packs are hardly tolerant of each other. They stake out territorial claims of land where they can sustain themselves off of good prey bases. Foreign Utahs that are caught on another pack's land are threatened and chased out. Death usually comes to those stupid enough to fight against the odds.
When a kill is made a packs behavior varies depending on the amount of food they have in possession. A small kill will be jealously hoarded by the dominant Utahraptor, and usually the subordinates are lucky to get a bite. However when larger kills are made the entire pack feeds at once. A hierarchy based on size is formed, and while equally sized Utahraptors may feed peacefully alongside one another to avoid conflict, smaller individuals are always bullied away, made to settle for scraps.
Cannibalism is a common occurrence when these smaller raptors do not get the hint and continue to persistently attempt to eat.
Breeding Habits
When it is time to breed, Utahraptors distinctly change their social behavior in an effort to breed with unrelated Utahs for a fresh genepool. The dominant pair of the pack will nest together, while subordinates set out on their own, either pairing up with other members of their pack or going out on their own to find a stranger. These bachelor males will roam and look for females that have dispersed. They regularly make a series of broadcast calls and change locations to avoid the attention of threats while at the same time making their presence known to untaken females.
Upon hearing a female respond, the male Utahraptor is quick to rush to her, but despite this speed, usually multiple males hear her call, and so multiple males end up courting her at the same time. However, lacking feathers, the Raptors are unable to win over a mate via displays, so they resort to a more graphic method. The male Utahraptors that find a female at the same time will often immediately dive into combat with each other, viciously attempting to kill one another in order to display their strength and impress the female.
These battles between males only get more and more chaotic the more males that participate. But at the end of the day, whether it is a duel between 2 or a brawl between 6, there will only be one male standing after the rest have either fallen or fled, and he is who the female chooses.
Once two Utahraptors have paired up, they seek out a suitable place to nest, taking into account prey availability, predator density, and availability of good nesting sites. (Dens, caves, etc.) This pair will temporarily abandon their pack(s) for the safety of their offspring, especially from larger and more dominant packmates. Utahraptors that end up partnerless or without offspring will generally return to their packs and assist the leading pair in raising their offspring.
Because of this benefit, the Alpha pair of a pack is highly aggressive to other nesting pairs. If they have a chance to, they will attempt to dispose of the nest or offspring of other Utahraptors (except rival Alpha pairs), in order to get them to return and assist them in rearing their clutch.
Because of this danger, along with the plethora of other predatory species on the island, the pair rarely hunts together. After mating each pair mate takes up their own duty. The female stays near the chosen nest site and prepares her nest, while the male goes off and provides food for them both. Once her eggs are laid, duties are routinely switched. One parent will go and hunt while the other guards the nest. Usually each parent has a 50/50 split of these two duties, though occasionally one may hunt more, the other may guard the nest more, etc.
This routine does not change much once the hatchlings are born either. Utahraptor chicks are fast growing, and at 5 weeks of age (0.5 growth) they are largely independent. Once this age is reached they go off on their own if the pack is currently full of adults (6 total), and their parents rejoin their pack. Some offspring have been known to challenge current pack members for a spot within the ranks in order to stay if the pack is full.
Fast Fact
Packing: 6 per pack
Nesting: 4 eggs per clutch
Aggression: High towards rival packs/foreign Utahs when in packs. Medium towards everything else.
Mating: Paired
Other: Offspring do not need to be kicked out and others can join the pack, but packs cannot exceed 6 members. Unless you are the main pair (alpha pair) you cannot nest in a pack of Utahs, no matter the current pack size.
