page_title: Feeding behaviour of Tyrannosaurus
section_title: Scavenging
hierarchical_section_title: Feeding behaviour of Tyrannosaurus / Scavenging
caption_attribution_description: Photo: cast of a Tyrannosaurus rex braincase at the Australian Museum, Sydney.
context_page_description: The feeding behaviour of Tyrannosaurus rex has been studied extensively. The well known attributes of T. rex are often interpreted to be indicative of either a predatory or scavenging lifestyle, and as such the biomechanics, feeding strategies and diet of Tyrannosaurus have been subject to much research and debate.
context_section_description: The debate about whether Tyrannosaurus was an active predator or a pure scavenger, however, is as old as the debate about its locomotion. Lambe (1917) described a good skeleton of Tyrannosaurus's close relative Gorgosaurus and concluded that it and therefore also Tyrannosaurus was a pure scavenger, because the Gorgosaurus teeth showed hardly any wear. This argument is no longer taken seriously, because theropods replaced their teeth quite rapidly. Ever since the first discovery of Tyrannosaurus most scientists have speculated that it was a predator; like modern large predators it would readily scavenge or steal another predator's kill if it had the opportunity.
  Paleontologist Jack Horner has been a major advocate of the idea that Tyrannosaurus was exclusively a scavenger and did not engage in active hunting at all, though Horner himself has claimed that he never published this idea in the peer reviewed scientific literature and used it mainly as a tool to teach a popular audience, particularly children, the dangers of making assumptions in science (such as assuming T. rex was a hunter) without using evidence. Nevertheless, Horner presented several arguments in the popular literature to support the pure scavenger hypothesis:
  Tyrannosaur arms are short when compared to other known predators. Horner argues that the arms were too short to make the necessary gripping force to hold on to prey. Other paleontologists such as Thomas Holtz Jr. and James Farlow, however, gave examples of animals that do not use their forelimbs to hunt such as wolves, seriemas and secretarybirds. Holtz later stated that the use of forelimbs are not the only viable way of prey capture giving examples of modern predators such as canids and hyaenids (hyenas). He also cited other extinct animals such as the Diatryma (also known as Gastornis) and Phorusrhacids. Gregory S. Paul cited thylacines as another example.
  Tyrannosaurs had large olfactory bulbs, suggesting a highly developed sense of smell which could sniff out carcasses over great distances, as modern vultures do. Because vultures are primarily scavengers, it has been suggested that such a highly developed sense of smell may imply that tyrannosaurs were as well. However, Farlow and Holtz have noted that a good sense of smell could also be used to detect live prey as well as for behaviors unrelated to food acquisition. Darla K. Zelenitsky, Francois Therrien and Yoshitsugu Kobayashi also discussed the Tyrannosaurus's sense of smell in their 2009 study and stated that it was not an indication of a particular feeding strategy the animal was using (predator versus scavenger), but indicate that tyrannosaurids such as Tyrannosaurus were active during low light conditions and may have used their sense of smell to search for food and navigate through large home ranges. In a 2013 lecture, Holtz. also noted that like Tyrannosaurus, wolves and raptors such as Velociraptor also had a good sense of smell. Others have argued that the primary scavenger hypothesis is implausible because the only modern pure scavengers are large gliding birds, which use their keen senses and energy-efficient gliding to cover vast areas economically. However, researchers from Glasgow concluded that an ecosystem as productive as the current Serengeti would provide sufficient carrion for a large theropod scavenger, although the theropod might have had to be cold-blooded in order to get more calories from carrion than it spent on foraging (see Metabolism of dinosaurs). They also suggested that modern ecosystems like Serengeti have no large terrestrial scavengers because gliding birds now do the job much more efficiently, while large theropods did not face competition for the scavenger ecological niche from gliding birds. However, further research by the same scientists found that the evolution of a terrestrial obligate scavenger was unlikely (read more on Ruxton & Houson's 2004 study below).
  Tyrannosaur teeth could crush bone, and therefore could extract as much food (bone marrow) as possible from carcass remnants, usually the least n
caption: Cast of the braincase at the Australian Museum, Sydney
exif: {}