Valley of the T. rex is a Discovery Channel documentary, featuring paleontologist Jack Horner, that aired on September 10, 2001. The program shows Horner with his digging team as they travel to Hell Creek Formation in search for dinosaur fossils, while also following Horner as he presents his view of the Tyrannosaurus as a scavenger rather than a predator, as it is often portrayed in popular culture.
| Valley of the T. rex | |
|---|---|
| Genre | Documentary |
| Narrated by | Jimmie Wood |
| Production | |
| Running time | 50 minutes |
| Original release | |
| Network | Discovery Channel |
| Release | September 10, 2001 |
| Related | |
| When Dinosaurs Roamed America | |
Plot
editThe program shows Horner and his digging team as they travel to the Hell Creek Formation in Montana, United States, and dig up dinosaurs.
The program also follows Horner as he presents arguments for his case of Tyrannosaurus as a scavenger. Horner argues that there is not the slightest evidence that Tyrannosaurus hunted its own prey, such as Chasmosaurus, Gryposaurus, and possibly even Edmontosaurus. Instead, Horner believes the evidence should be clear that Tyrannosaurus was a scavenger.
Tyrannosaurus becomes depicted as Horner imagines it: a big, slow-moving animal, traveling across the landscape in search of a carcass. Horner thinks Tyrannosaurus would have a repulsive look: A dark body, a red head, and it would give off a terrible smell. This would help it frighten away other meateaters, such as Velocisaurus, from carcasses. His description of T. rex is big, nasty, and stinky.
About the program
edit- When Horner examines the anatomy of Tyrannosaurus in the program, he mostly use the specimen MOR 555 ("Wankel Rex") as reference. This specimen was found by Kathy Wankel in 1988, and was the first specimen of the genus with a well-preserved forelimb.
- The program features Horner and his team as they dig up 5 new Tyrannosaurus specimens.
- The computer animation in the program was made by Meteor Studios. Some of the animations are taken from one of Discovery Channel's other programs about dinosaurs, When Dinosaurs Roamed America.
Criticism
editSince Valley of the T. rex was shown on television, it has been met by criticism. Many of the arguments Horner uses to support his case have been examined by other paleontologists, who do not agree that they conclusively show that Tyrannosaurus was an obligate scavenger.[1] As for Tyrannosaurus‘s short forelimbs, it has been pointed out that predators like wolves and hyenas do not use their front legs to take down prey. Moreover, hyenas, like Tyrannosaurus, have jaws and teeth to crush bone, yet they use it to hunt their own prey.[2]
In the program, Horner measures the leg bones of MOR 1128, or "G-rex", one of the skeletons which were shown in the program as it was dug up. The narrator says that "G-rex" was found in a rock layer 90 meters below where "Wankelrex" was found, and Horner says "G-rex" are thought to be 3 million years older than other known specimens (like "Wankelrex"). Horner also says that "G-rex" have thighbone and shinbone of equal length, while "Wankelrex", have longer thighbone than shinbone. Horner argues it is an indication that Tyrannosaurus over time lost the ability to run and evolved to more specialization as a walking scavenger. It has been argued by Garner, however, that the shinbone of "Wankelrex" are restored from broken fragments,[3] making it inappropriate as reference in comparative morphology. Also, according to other reports, "G-rex" also had longer thighbone (1.26 meters)[4] than shinbone (1.12 meters).[5] Holtz also points out that longer thighbones than shinbones is a condition also found in horses, which are fast running animals. A shorter shinbone might be compensated by a relatively long metatarsus, which is seen both in horses and tyrannosaurids.[1]
Other scientists have argued that Tyrannosaurus could have had a well-developed sense of sight with binocular vision, typical of a predator,[6] and a well-developed sense of smell in Tyrannosaurus could have been used for hunting, rather than just finding carcasses. Evidences for a predatory lifestyle in Tyrannosaurus includes discoveries of skeletons from herbivorous dinosaurs like Gryposaurus and Chasmosaurus, with evidence of healed bitemarks on them, indicating they survived attacks from tyrannosaur-like predators, possibly Tyrannosaurus and Labocania.
References
edit- ^ a b Holtz T.R.jr. "A critical re-appraisal of the obligate scavenging hypothesis for Tyrannosaurus rex and other tyrant dinosaurs", in Tanke D.H., Carpenter K & Skrepnick M.W. Mesozoic Vertebrate Life (Indiana University Press, 2001), p. 370-396.
- ^ Holekamp, K. E.; Smale, L.; Berg, R.; Cooper, S. M. (March 24, 2009). "Hunting rates and hunting success in the spotted hyena (Crocuta crocuta)". Journal of Zoology. 242 (1): 1–15. doi:10.1111/j.1469-7998.1997.tb02925.x. Retrieved March 19, 2023.
- ^ http://www.cmnh.org/dinoarch/2001Sep/msg00522.html Archived October 21, 2013, at the Wayback Machine.
- ^ Larson P.L., "Variation and Sexual Dimorphism in Tyrannosaurus rex", in Larson P.L. & Carpenter K, Tyrannosaurus rex, the Tyrant King (Indiana University Press, 2008), p. 103-130.
- ^ Horner J.R. & Padian K. (2004), "Age and growth dynamics of Tyrannosaurus rex", Proceedings of the Royal Society of London B 271(1551): p. 1875-1880.
- ^ Stevens K.A. (2006), "Binocular vision in theropod dinosaurs" Archived March 23, 2012, at the Wayback Machine, Journal of Vertebrate Paleontology 26(2): p. 321-330.