Dinosaur Blood Found Inside 115-Million-Year-Old Bones
Traces of blood have been found inside the fossil bones of a meat-eating dinosaur from Brazil that lived 115 million years ago.
Scientists have found traces of blood inside dinosaur bones that are 115 million years old, and this time they say the evidence is chemical, not just a shape in the rock. The discovery suggests that some delicate biological material can survive far longer than most researchers thought possible.
The blood cells were still inside the bone's own tiny channels
The dinosaur is Aratasaurus museunacionali, a meat-eating, two-legged dinosaur whose remains were found in northeastern Brazil. An international team led by Curtin University examined its limb bones and found many red blood cells that had been turned to mineral, still sitting inside vascular canals — the narrow tunnels that once carried blood vessels through the bone.
Chemical analysis then turned up preserved heme molecules. Heme is the part of the oxygen-carrying substance in red blood cells that actually grabs hold of oxygen, and finding it inside the fossilised cells is what makes this a chemical confirmation rather than a guess. Earlier studies had spotted structures that looked like blood cells in ancient fossils, but had not shown that these particular molecules were still present inside them. The team also found amino acids linked to collagen, the tough material that gives bone and connective tissue their strength.
A mineral turned the burial site into a time capsule
The preservation seems to be tied to a mineral called hausmannite, which helped steady the fossilised blood cells and keep their molecular pieces intact across an enormous span of geological time. In effect, it built a natural time capsule around microscopic evidence of the animal's biology.
Where the dinosaur was buried probably mattered too. Researchers suspect the animal was covered by sediment quickly, in a place with little oxygen and plenty of microbial activity. Those conditions may have protected material that would normally have broken down and disappeared.
The work was published in the Proceedings of the National Academy of Sciences and brought together scientists from Curtin University's School of Earth and Planetary Sciences, the Japan Agency for Marine-Earth Science and Technology, the Brazilian National Museum, the Regional University of Cariri and Johns Hopkins University.
Why one old blood cell changes the search for ancient life
Paleontologists had long assumed that blood-related molecules could not survive such deep time. Kliti Grice, a John Curtin Distinguished Professor who led the study, called the result a landmark discovery and said it extends the known fossil record of blood while offering a direct molecular window into the physiology of long-extinct animals.
Grice also said the findings challenge longstanding assumptions that certain biological molecules, such as the oxygen-carrying substance in red blood cells, cannot survive deep time, opening new avenues for studying the evolution of blood, metabolism and even activity levels in ancient animals.
Martin Van Kranendonk, head of Curtin University's School of Earth and Planetary Sciences, said the results are changing how researchers understand the preservation of molecular structures over vast timescales. One practical consequence is that other fossils may already hold molecular information that ordinary examinations have overlooked. Another is further afield: if fragile biological structures can last for millions of years under the right conditions, that could help scientists know what to look for when hunting for traces of ancient life in extreme environments, including beyond Earth.