Tyrannosaus Rex

The Tyrannosaurus Rex was a ferocious animal. It's name meant "Tyrant Lizard King".  It had 8 inch (20 cm) teeth! The first T. Rex fossil found was by Barnum Brown in 1902 in Hell Creek, Montana. The T. Rex had forward facing eyes, allowing it to focus both eyes on a target. It also gave the T. Rex good perception of its surroundings. 

The Tyrannosaurus had three different species, the largest one being T. imperator.  

 Tyrannosaurus had one of the most powerful bite force of any animal that ever lived, approximately 34,000-63,500 newtons! Tyrannosaurus was an apex predator in the  Late Cretaceous. It hunted a variety of herbivore dinosaurs such as Parasaurolophus, Triceratops, Edmontosaurus, and Ankylosaurus, to name a few. The T. Rex was extremely smart, allowing it to easily take down it's prey.   

                         FUN FACTS

The Tyrannosaurus can live for approximately 30 years. The female Tyrannosaurus were larger than the males. It was not the largest meat eating dinosaur. T. Rex weighed around 8 tons. T. Rex is 12 feet tall at the hip!

The first documented Tyrannosaurus rex tooth was discovered in July 1874 on South Table Mountain, Colorado, by Peter T. Dotson, a student at Jarvis Hall, under the guidance of Prof. Arthur Lakes. Later, in the early 1890s, John Bell Hatcher collected skeletal remains in eastern Wyoming, initially thought to belong to Ornithomimus grandis (now Deinodon), but they were later identified as T. rex fossils.

In 1892, Edward Drinker Cope uncovered two vertebral fragments of a large dinosaur, believing them to be from a ceratopsid species he named Manospondylus gigas, referring to the porous nature of the bones. By 1907, Hatcher had reclassified these remains as those of a theropod. Henry Fairfield Osborn recognized the similarities between M. gigas and T. rex as early as 1917 but refrained from merging the two species due to the fragmentary condition of Manospondylus fossils. In 2000, the Black Hills Institute discovered a partial Tyrannosaurus skeleton at what may have been the original M. gigas site.

Barnum Brown, assistant curator at the American Museum of Natural History, found the first partial T. rex skeleton in eastern Wyoming in 1900. Two years later, another partial skeleton was unearthed in Montana's Hell Creek Formation, including 34 fossilized bones. Brown noted the specimen's unique features, which had not been described before. In 1905, Osborn officially named the species Tyrannosaurus rex, deriving its name from Greek and Latin to mean "King Tyrant Lizard," highlighting its imposing size and dominance.

Osborn initially named another specimen Dynamosaurus imperiosus in 1905, but in 1906, he recognized that both skeletons belonged to the same species and favored Tyrannosaurus as the official name. The T. rex type specimen was sold to the Carnegie Museum of Natural History for $7,000 in 1941. The Dynamosaurus remains are now housed at the Natural History Museum in London. The name Dynamosaurus was later honored in 2018 with the naming of Dynamoterror dynastes, a new tyrannosaurid species.

Between the 1910s and 1950s, Barnum Brown's discoveries remained the only known T. rex fossils, as economic and global conflicts hindered further paleontological excavations.

Scientists have proposed a wide range of running speeds for Tyrannosaurus rex, being around 9 meters per second (32 km/h; 20 mph), but estimates vary from 4.5–6.8 meters per second (16–24 km/h; 10–15 mph) to a highly unlikely 20 meters per second (72 km/h; 45 mph). Due to its large, bulky frame, T. rex was likely slower compared to more streamlined theropods like Carnotaurus and Giganotosaurus. Researchers have used various estimation techniques since fossilized trackways of large theropods show walking behavior but lack evidence of running.

A 2002 study applied a mathematical model to living animals, including alligators, chickens, and ostriches, to estimate the leg muscle mass needed for high-speed running (over 40 km/h or 25 mph). While some scientists argue that features like hollow bones could have lightened its body to around 4.5 metric tons, making running more feasible, others contend that achieving speeds over 40 km/h would have required exceptionally large leg muscles—comprising up to 86% of the dinosaur's total body mass. Moderate speeds would still demand substantial muscle, and if muscle mass were limited, T. rex could likely only walk or jog at around 18 km/h (11 mph).

Paleontologist Thomas Holtz observed that tyrannosaurids had notably elongated distal leg components and an interlocked metatarsus, forming an "arctometatarsus," which may have helped improve locomotion efficiency. These adaptations allowed T. rex to transfer movement forces effectively, potentially improving its ability to walk long distances.

A 2020 study further indicated that Tyrannosaurus and its relatives were exceptionally efficient walkers. Research comparing more than 70 theropods found that long legs in small-to-medium species aided running, while in larger theropods like T. rex, longer legs reduced energy expenditure for walking, improving foraging efficiency. This suggests that T. rex used a slow stalking approach before launching a short burst of speed, somewhat analogous to modern wolves. Evidence also indicates that some tyrannosaurids may have hunted in groups.

In 2021, a study estimated T. rex's preferred walking speed at 1.28 meters per second (4.6 km/h; 2.9 mph), considering how its tail swayed rhythmically, acting like a spring to enhance energy efficiency. Earlier studies suggested a top running speed of 27 km/h (17 mph), but a 2017 model argued that speeds exceeding 18 km/h (11 mph) would have placed excessive stress on the bones, potentially causing fractures. This limitation likely applied to other giant theropods, such as Giganotosaurus and Mapusaurus.

However, a 2019 study proposed that Tyrannosaurus was more maneuverable than similarly sized theropods due to low rotational inertia and powerful leg muscles. The findings suggest T. rex could pivot rapidly, possibly using a planted foot while swinging the other leg during pursuits. This agility might have contributed to the evolutionary success of tyrannosaurids.

Research by Lawrence Witmer and Ryan Ridgely of Ohio University indicates that Tyrannosaurus rex possessed heightened sensory abilities comparable to other coelurosaurs. These included rapid and coordinated eye and head movements, an enhanced sensitivity to low-frequency sounds—potentially enabling it to track prey over long distances—and a highly developed sense of smell. A separate study by Kent Stevens found that T. rex had exceptional vision, with a binocular range of 55 degrees, surpassing that of modern hawks. Stevens estimated its visual acuity as 13 times that of a human and greater than an eagle's, allowing it to distinguish objects up to 6 km (3.7 mi) away.

Paleontologist Thomas Holtz Jr. suggested that T. rex's superior depth perception was a crucial adaptation for hunting well-armored prey like Triceratops and Ankylosaurus, requiring precise attacks. By contrast, theropods such as Acrocanthosaurus had more limited depth perception due to hunting large sauropods.

Though no T. rex sclerotic ring has been found, Kenneth Carpenter estimated its size based on Gorgosaurus, suggesting T. rex's eyes were large but likely adapted for daytime hunting rather than low-light vision. Additionally, T. rex had large olfactory bulbs, implying an exceptional sense of smell akin to modern vultures, possibly allowing it to detect carcasses from great distances. Among 21 sampled non-avian dinosaurs, T. rex ranked highest in olfactory sensitivity.

Anatomical studies indicate T. rex had an unusually long cochlea, likely aiding in its ability to perceive low-frequency sounds, which may have been vital to its behavior. Studies of related species suggest tyrannosaurs had highly sensitive snouts, possibly used for nest maintenance, hatchling care, or precise prey handling. Research on neurovascular canals in its jaws suggests T. rex could finely detect differences in material and movement, adjusting its feeding strategy accordingly. These adaptations may have also supported functions like thermoregulation or social communication.

Regarding intelligence, studies on brain size suggest T. rex had one of the largest brains among non-avian dinosaurs, with an encephalization quotient comparable to a chimpanzee’s, though reptilian and mammalian EQs differ. Its cerebrum-to-brain ratio was similar to some extant birds and alligators, indicating notable cognitive abilities for a reptile.