Yutyrannus

Weight: 1.52 tons

Length: 30 feet

Height: Up to 12 feet

Social Unit: Solitary

Status: Lower Risk (pre-Xibalba), Critically Endangered (post-Xibalba)

Native to: Aztlan

Habitat: Mountain Forests

The Yutyrannus is a massive carnivorous dinosaur native to the mountain forests of the Planet Aztlan. Yutyrannus are very elusive creatures, rarely coming down from the mountains into the valleys or altiplano where sentients live. However, sentients who enter the mountains must be extremely careful, as Yutyrannus will usually not hesitate to attack and consume any sentient that enters their territory. To survive their cold and often snowy mountain habitat, Yutyrannus are covered in a thick layer of feathers, with only the feet, vestigial arms, and head being exposed. While these feathers can be any variety of colors during the summer, Yutyrannus will shed their colorful coats during the early autumn in exchange for a thicker brown and white coat that lasts through late autumn and the entire winter until late spring. Their skin pigmentation will change to similar shades as well. As a result, Yutyrannus can be especially hard to find during the winter, as they are perfectly camouflaged by snowdrifts and snow-covered pines. Yutyrannus is easily the top predator of Aztlan's mountain ecosystem, as the larger and more dangerous T. Rex, Spinosaurus, and Giganotosaurus (the only Aztlanian beasts that can compete with Yutyrannus) can only be found at much lower altitudes. In the high mountain altitudes, Yutyrannus is thus free to prey on Ankylosaurus, Guanacos, Vicunas, Deer, Rheas, Mountain Tapirs, Therizinosaurus, and Ugrunaaluk virtually unopposed.

Although they usually dominate the mountain ecosystem, the smaller but related Nanuqsaurus can occasionally drive a Yutyrannus out of the area due to the fact that they hunt in packs. However, Nanuqsaurus often lives at slightly lower altitudes then Yutyrannus, so the two species do not come into contact very much. Yutyrannus are most famous for having the loudest, most blood-curdling roar of any animal species in the entire South Galaxy, being said to put even the bravest dragons to flight. The natural acoustics of Aztlan's mountains amplify the roars and add an echo effect to them, causing them to strike intense fear into the hearts of mountain peoples, even if they do not often see the beasts. As a result, the creatures are often referred to as Cehpayahuimitl, meaning "Snow Screamers" in Aztlanian.

Yutyrannus usually live to be around 30 years old, and reach sexual maturity at 10-11 years of age. These creatures do not mate for life, with the male simply leaving the female to care for the single egg after it is laid. The egg is incubated for around 3 months, and the hatchling is fed regurgitated meat by its mother for another few months until she teaches it to hunt. Once the hatchling learns to hunt, it leaves its mother and begins life on its own. Like almost all dragons and most dinosaurs, Yutyrannus hatchlings will imprint on the first living thing it sees when it hatches out of its egg, meaning it could in theory be tamed if a sentient stole an egg from a nest and watched it hatch. However, Yutyrannus are so dangerous and elusive that this was never even attempted until Neza managed to hatch one just before the Xibalba incident.

Though elusive, Yutyrannus were once plentiful all over Aztlan. However, after the asteroid Xibalba slammed into the planet and the cataclysm that ensued, Yutyrannus were nearly faced with extinction, suffering almost 80% population loss. By the time Aztlan's people began to rebuild from the disaster, there were only a few isolated Yutyrannus populations left, mostly in the mountains surrounding the northern and western shores of Lake Coxcote. This problem was made worse during the Great Tatian War, when many eggs were stolen from the already endangered species so that the Aurean Alliance forces could have a tamed population of these beasts for use in war. However, after the war, this population of Yutyrannus was reintroduced to mountainous national parks all over the galaxy, spreading the species to new planets. Some were even returned to Aztlan.