--- title: Researchers Have Discovered Secret to T. Rex Teeth description: Researchers found that the saw-like internal tooth structure of carnivorous dinosaurs was important in their success as predators. canonical: https://time.com/3977490/tyrannosaurus-rex-trex-dinosaur-teeth/ author: Daniel White article:opinion: false article:content_tier: free article:published_time: 2015-07-29T20:45:57.000Z article:modified_time: 2026-08-04T07:58:23.038Z article:section: Science og:title: Scientists discover secret to T. Rex's deadly teeth. og:description: Teeth were like steak-knives; able to crush bone and tear flesh. og:url: https://time.com/3977490/tyrannosaurus-rex-trex-dinosaur-teeth/ og:site_name: TIME og:image: https://static.time.com/v3/assets/bltea6093859af6183b/blt5a489bb1202c30e1/69885d1b5f570f54a8b1cad3/t-rex.jpg?branch=production&width=1200&quality=75&auto=webp&crop=16:9 og:image:width: 5100 og:image:height: 2869 og:image:alt: t rex eats triceratops og:type: article twitter:card: summary_large_image twitter:title: Scientists discover secret to T. Rex's deadly teeth. twitter:description: Teeth were like steak-knives; able to crush bone and tear flesh. twitter:image: https://static.time.com/v3/assets/bltea6093859af6183b/blt5a489bb1202c30e1/69885d1b5f570f54a8b1cad3/t-rex.jpg?branch=production&width=1200&quality=75&auto=webp&crop=16:9 ---  # Researchers Have Discovered What Made T. Rex Teeth So Deadly > Sponsored content. Supplied in partnership with TIME. 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Future Proof is free at time.com/newsletters. ### Sources * TIME Newsletters: [time.com/newsletters](/c/time-nl-futureproof-2026q3/newsletters?i=1d731298-1f23-44b7-88e2-b12856c33e4b&cr=time-nl-futureproof-2026q3-v1) ## Video: Why Plant-Eating Dinos Might Have Avoided The Equator [Watch (HLS stream): Why Plant-Eating Dinos Might Have Avoided The Equator](https://cdn.jwplayer.com/manifests/IxMjFM9L.m3u8) (1:31)  _Published 2015-06-16. We've known that herbivorous dinosaurs avoided tropical areas during the Triassic Period, but no one knew why. A new study has an answer._ by [Daniel White](https://time.com/author/daniel-white/) ## Daniel White Jul 29, 2015 8:45 PM UTC  A Tyrannosaurus Rex eats the carrion of a dead Triceratops in prehistoric wetlands. A Tyrannosaurus Rex eats the carrion of a dead Triceratops in prehistoric wetlands. Getty Images by [Daniel White](https://time.com/author/daniel-white/) ## Daniel White Jul 29, 2015 8:45 PM UTC Though notoriously short-armed, the T. Rex had other genetic advantages: namely, its teeth. Researchers have found that the saw-like internal tooth structure of carnivorous dinosaurs like the Tyrannosaurus Rex may have played an important role in their success as predators. In the study [published in Scientific Reports](http://www.nature.com/articles/srep12338), researchers discovered that the teeth of meat-eating Theropod dinosaurs featured specially layered arrangements of dentine, a hardened tissue which helped not only strengthen the tooth, but also to enlarge the tooth’s jagged edges. This tooth structure allowed them to develop a “hypercarnivorous feeding style,” the study says, with the ability to crush bones and feed on other large animals. When teeth were worn out or lost, these dinosaurs were able to grow new teeth to replace them. Growing new teeth could take up to two years, however, which is why these dinosaurs needed a tooth structure strong enough to last – and to keep up that meaty diet. ## Transcript [00:00] It has long been known that large herbivorous [00:02] dinosaurs did not populate tropical areas during the [00:05] late Triassic period. Which was about 230- 200 million [00:09] years ago, but oddly enough no one knew why. Well [00:13] according to a new study it was the unstable climate [00:16] that kept those herbivores from migrating to tropical [00:19] areas. As one of the researches from the study put it. [00:22] Large, warm blooded dinosaurian herbivores weren't [00:25] able to exist close to the equator. There was not [00:28] enough dependable plant food. Simply put, no plants, [00:31] no plant eating dinosaurs. Scientists say carbon [00:34] dioxide levels then were four to six times what they are [00:37] now. Which made those regions more arid and [00:40] unfriendly to plants. The study also suggests that [00:43] wildfire's persisted during this period of time with [00:45] varying intensity, which killed off more plant. Two [00:49] legged carnivorous dinosaurs could survive in the [00:51] tropical areas throughout the Triassic Period. But the [00:54] unstable climate kept the herbivorous dinosaurs out of [00:57] tropical areas until the beginning of the Jurassic Period. [01:00] In order to conduct the study, researchers analyzed [01:02] fossils, charcoal left by ancient wildfires, and stable [01:06] isotopes from organic matter and carbonate nodules [01:09] that formed in ancient soils. The study's lead [01:11] researcher, Jessica Whiteside, said, " Each dataset [01:14] complements the others, and they all point towards [01:17] similar [ climate ] conditions ." Whiteside also points [01:20] out that if the human race doesn't change as it relates [01:22] to carbon emissions, We could experience similar [01:25] conditions in the not so distant future. 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