Recommended Free Tools
iTechGuides is reader-supported. When you buy through links on our site, we may earn an affiliate commission. As an Amazon Associate I earn from qualifying purchases. Learn more
A 2022 study used chemical signatures in fossil bone to infer that the ancestors of dinosaurs and pterosaurs had high metabolic rates, and that several dinosaur groups retained them. The finding is an inference from molecular proxies—not a direct measurement of extinct animals’ metabolism or body temperature—and scientists have disputed how strongly the evidence supports it.
What the 2022 study found
In a Nature paper published May 25, 2022, Jasmina Wiemann and colleagues analyzed modern and fossil amniote bones using in-situ Raman and Fourier-transform infrared spectroscopy. They measured chemical signals associated with metabolic lipoxidation—the oxidation of lipids during metabolism—and used those signals to estimate metabolic patterns across living and extinct animals. The study describes the approach as quantifying the in-vivo accumulation of metabolic lipoxidation signals in bone.
The authors inferred that metabolic rates consistent with endothermy evolved independently in mammals and plesiosaurs, and were already present in the ancestral ornithodiran lineage—the group that includes dinosaurs and pterosaurs. They reported high rates in pterosaurs, ornithischians, sauropods, and theropods, and a later reduction in metabolic ability among ornithischians toward an ectothermy-like condition. The paper also reported no correlation between atmospheric oxygen concentration and metabolic rates. These are broad patterns inferred by the authors, not evidence that every species within a group had identical physiology. The PubMed abstract summarizes the findings.
The Tool Desk
Outbyte PC Repair FREEClear out junk files and repair common Windows errorsFree Scan →Outbyte Driver Updater FREEScan for outdated or missing drivers - takes under a minuteDriver Scan →How fossil chemistry can suggest metabolism
The method does not find a fossil’s metabolic rate preserved as a number. Instead, it detects chemical signals interpreted as products of metabolic lipoxidation, compares them with signals in living animals, and uses those relationships to infer rates in extinct lineages. The researchers then applied ancestral-state reconstruction to estimate what metabolic patterns may have characterized earlier branches of the evolutionary tree.
#1 Best Overall
- Resin Cast Replica
- 5.5 inches
The distinction matters: spectroscopy measures chemical features in the bone samples; the interpretation of those features as metabolic evidence, and the estimates of ancestral metabolism, depend on the proxy’s calibration and the reconstruction method. Wiemann and colleagues explicitly cautioned: “However, there is no proxy that enables the direct reconstruction of metabolic rates from fossils.”
What “bird-like metabolism” means—and what it does not
“Bird-like” refers to the study’s inference of high metabolic performance along the bird lineage and high ancestral rates in ornithodirans. It does not mean that every dinosaur had the physiology of a modern bird. The paper itself describes variation among groups, including the inferred shift among ornithischians toward reduced metabolic abilities.
Rank #2
- 【Home Office Desktop Shelf Decor 】Dinosaur head sculptures skull model is hand cast from high-quality solid resin. The surface is made of antique craftsmanship, and the convincing colours and details make it look very realistic and eye-catching. Add some aesthetic to your room
- 【Supplement Your Collection】T-Rex is one of the most popular dinosaurs in the world. For dinosaur lovers or palaeontology lovers, the tyrannosaurus rex skull is a fantastic replica. It will also be a fun teaching tool for any child or teen
- 【Home Decor and Conversation Starter】A lifelike dinosaur skeleton decor. This impressive sculpture looks great on a table or bookshelf. It will be a great conversation starter and conversation piece for any family
- 【Suitable for Many Occasions】This Tyrannosaurus Rex skull replica comes with a metal base. There are 4 non-slip pads on the bottom of the stand to protect the surface of your furniture. It can be placed on various occasions such as office, hallway, TV cabinet, wine rack, living room, etc
- 【Perfect Christmas/Birthday Gift】10.2x 5.9x 11.8 inches.It only takes 2 minutes to complete the installation.Give it as a gift to children, adults, husbands, and friends, no one will refuse it
Nor is “warm-blooded” a complete summary of the result. Endothermy generally refers to generating substantial body heat internally, but metabolic rate and body-temperature regulation are related rather than interchangeable concepts. This study used a molecular proxy to infer metabolic patterns; it did not directly measure fossil body temperatures.
Why researchers challenged the conclusion
In a 2023 Nature Matters Arising, Ryuji Motani and colleagues accepted the goal of developing biomarkers but argued that the inference from ALE biomarkers and ancestral-state reconstruction was not adequately supported. They wrote: “However, we argue that the inference of endothermy based on ALE biomarkers and ancestral state reconstruction is poorly supported by the current evidence.” Their critique addresses both the proxy and the reasoning used to infer ancestral states, rather than simply asserting that dinosaurs were uniformly cold-blooded. Motani and colleagues’ article sets out their concerns.
Rank #3
- Utahraptor was a large theropod dinosaur that lived during the Early Cretaceous period, known for its sharp claws and hunting abilities
- This replica is based on a real Utahraptor fossil discovered in Utah, accurately capturing the shape and detail of the original claw
- The Utahraptor’s curved claw was used for gripping and slashing, making it a key tool for hunting prey
- Cast in durable resin, this 5.5-inch replica offers museum-quality detail and texture
- Made in the USA, this fossil reproduction is perfect for collectors, educators, and dinosaur enthusiasts
Wiemann and colleagues published a reply in the same issue, defending the ALE proxy and responding to the critique. The existence of that reply does not by itself resolve the dispute; the reply and the Matters Arising document competing interpretations of the evidence. The sources establish a scientific disagreement, not a final resolution.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.How claims about fossil organics fit in
The metabolic paper concerns chemical signatures interpreted as products of fossilization. It is not a report of intact dinosaur DNA or a direct assay of preserved living tissue. Separate studies have debated whether organic remnants in dinosaur bones are endogenous—that is, derived from the animal—or instead reflect later material and microbial activity.
Rank #4
- IT FROM XUQCAH MATERIAL AND FOIMOJSK PAR ENT AND Thurder LOVER
- Museum Quality Replica
- Please thoroughly read discription
- A 2019 study of Cretaceous dinosaur bone argued that purported soft tissues differed chemically and structurally from collagen and discussed recent organic material and microbial communities. The eLife paper addresses that preservation question.
- A 2025 study of an exceptionally preserved Edmontosaurus sacrum reported combined analytical evidence supporting endogenous collagenous remnants. The Analytical Chemistry paper concerns collagenous material, not the validity of the metabolic proxy.
Evidence about whether collagen or other organic remnants survive in fossils does not, on its own, confirm or refute the 2022 metabolic inference. Those are related but distinct questions.
Free tools Windows power users keep installed
One-click scans. No signup required.
So, were dinosaurs warm-blooded?
The 2022 study supports the possibility that many dinosaur lineages had high metabolic rates consistent with endothermy, and it proposes that high rates were ancestral to ornithodirans. But the result comes from an indirect molecular proxy and an evolutionary reconstruction whose interpretation has been challenged. The most accurate answer is that this study contributes evidence for high metabolism in several groups; it does not settle the physiology of all dinosaurs or provide a direct measurement of their body temperature.
Quick Recap
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
