Researchers Determined T. rex Had Warm Blood
New data confirms Tyrannosaurus rex maintained a body temperature near 97 degrees, suggesting endothermic regulation.
Updated on Oct. 9, 2026 in Geology
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Researchers have determined that Tyrannosaurus rex maintained a warm-blooded body temperature of 97.3 degrees Fahrenheit. This finding relies on analysis of tooth enamel from fossils discovered in Montana.
Why it matters
Understanding the metabolic status of dinosaurs provides insight into their evolutionary capabilities and behavior as apex predators in Cretaceous ecosystems. This research clarifies whether these giants relied on internal thermal regulation or external environmental sources.
Analysis of three T. rex teeth yielded a temperature of 97.3 degrees Fahrenheit, with a 4.5 degree margin of error. Researchers utilized a tungsten carbide drill to extract 5 milligrams of enamel per tooth for isotopic ratio measurement.
The details
The team utilized the clumped isotopes method, which measures the concentration of heavy isotopes of carbon and oxygen that bond together within mineral structures. Because tooth enamel forms internally at the animal's core temperature, the specific ratios of these isotopes function as an environmental record of the animal's internal heat. By comparing these ratios to crocodilian teeth from the same formation, researchers distinguished between ambient environmental temperatures and the dinosaur's internal regulation.
Timeline
66 million years ago: Tyrannosaurus rex roamed western North America.
October 7, 2026: Research published in Science Advances.
The Tech Race
This finding settles a major point in the broader debate regarding dinosaur metabolism by providing an empirical temperature reading. It stands in contrast to prior thermal models that relied solely on growth rates or skeletal morphology.
This discovery refines the scientific understanding of how large predators functioned within the Cretaceous food web. It shifts the baseline for future paleontological studies concerning the energy requirements of apex predators in the United States fossil record.
The takeaway
The study establishes that T. rex operated at a metabolic level similar to modern mammals, with a temperature close to the human average of 98.6 degrees. Watch for follow-up studies applying this isotope method to other theropod species to determine if this thermal regulation was unique to the T. rex lineage.
Further reading
Explore deeper insights into prehistoric structures and Earth history in our Geology section.
Source note: This article includes information reported by The Star.
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