Tyrannosaurus rex only became a giant late in life

The skeletons of Tyrannosaurus rex are terrifyingly huge – for example the “Tristan” specimen in the Berlin Museum of Natural History. In the past, however, various bones were found that look as if they came from miniature editions of the T. rex .

For decades, researchers have been arguing whether these are independent, smaller species or early offspring by the famous predatory dinosaur. Holly Woodward from the Oklahoma State University Center for Health Sciences in Tulsa has now examined the bones of two specimens of such “dwarf tyrants” (Nanotyrannus), the horse-sized skeletons of “Jane” and “Petey” from the Burpee Museum of Natural History in Illinois, USA ,

Das Skelett des Tyrannosaurus Rex namens

The skeleton of the Tyrannosaurus Rex named “Tristan Otto” is still exhibited in the Natural History Museum in Berlin, is 2020 but after … Photo: Britta Pedersen / dpa

Your research team comes to the conclusion that the skeletons are from young T. rex , not of adult specimens of other species. The unwieldy, bulky tyrannosaurs were agile, slim and light-footed hunters with knife-like teeth in their youth, the researchers write in the journal “Science Advances”.

With 15 T. rex were hardly bigger than a horse

Apparently Tyrannosaurus rex went through a phase of exponential growth towards the ten meter long giant dinosaur with bone-grinding teeth quite late in his life. In this way, young animals would have taken other niches in the ecosystem than the adult ones and thus avoided competition.

Holly Woodward von der Oklahoma State University in Tulsa hat die Mikrostruktur der Knochen des T. rex-Teenagers

Holly Woodward from Oklahoma State University in Tulsa has the microstructure of the bones of T. rex teen “Jane” … Photo: Holly Woodward

The knowloedge The development of the giant lizards is often incomplete, as museums prefer to collect the largest, most impressive finds of a kind, the researchers explain. Many saurians therefore lacked young specimens, the examination of which would indicate that the primeval lizards had grown up. The T. rex was no exception – and “Jane” and “Petey” were a great stroke of luck. They were probably about 13 and 15 years old when they died.

eating machine only with 20 Full grown years

In their youth the predatory dinosaurs apparently grew at rates similar to those of today's birds and mammals the researchers from the bone analysis. However, there were probably big differences from year to year depending on the food supply. The dinosaurs were probably only grown up to 20 years, whereby their physical appearance immensely changed from the agile hunter to cumbersome eating machine changed. Annett Stein (dpa)

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