A recent study investigates the upper limits of dinosaur sizes, highlighting the case of the carnivorous Tyrannosaurus rex. Researchers employed computer modeling to project that T. rex could have been up to 70% heavier than current fossil findings indicate.
In a newly released study featured in the journal Ecology and Evolution, researchers examine how large dinosaurs could potentially grow, using the well-known carnivore, Tyrannosaurus rex, as a focal point. By utilizing computer models, Dr. Jordan Mallon of the Canadian Museum of Nature and Dr. David Hone of Queen Mary University of London estimated that T. rex might have weighed 70% more than what fossil evidence currently shows.
The researchers highlight that the enormous sizes reached by dinosaurs continue to captivate our curiosity, raising fascinating questions about the evolutionary processes that allowed these creatures to grow so large. Ongoing debates about which dinosaur species claims the title of the largest—whether within its own category or in history—persist.
Most known dinosaur species are represented by just a few fossils, making it highly improbable that these specimens encompass the full range of their size potential. This leads to the lingering inquiry: what were the actual sizes of the most massive individuals, and are we likely to discover them?
To explore this inquiry, Mallon and Hone implemented computer modeling to analyze a population of T. rex. They considered multiple factors including population size, growth rates, lifespan, and the gaps within the fossil record.
T. rex was selected for this modeling effort due to its familiarity, coupled with already established estimates for many relevant attributes. They modeled the size variability among adult T. rex, taking into account both potential sexual dimorphism and data derived from large modern alligators, which share a close genetic link to dinosaurs.
The paleontologists discovered that the largest known fossils of T. rex likely fall within the top 1% of size estimates. However, to uncover a specimen that ranks in the top 0.01%—a one-in-ten-thousand individual—researchers would need to continue excavating fossils at the current pace for approximately 1,000 more years.
The models suggested that the heaviest T. rex ever could have existed (one in 2.5 billion specimens) might have been 70% heavier than the heaviest known fossils (estimated at 15 tonnes compared to 8.8 tonnes) and 25% longer (15 meters as opposed to 12 meters).
These figures are projections based on the model, but the patterns of discovering large specimens among modern species indicate that even bigger dinosaurs likely roamed the Earth, waiting to be found. “Certain isolated bones and fragments suggest the existence of larger specimens than those currently represented in our skeleton displays,” remarked Hone.
This research contributes to ongoing discussions about the largest prehistoric animals. Many large dinosaurs from different groups are represented by only a single, high-quality specimen, making it hard to ascertain whether that example is truly representative of the species’ average size. An ostensibly massive species might rely on a single large individual for its classification, while a smaller species could be based on a notably diminutive specimen—neither of which accurately reflects the species as a whole.
The likelihood of paleontologists uncovering the largest individual for any species remains exceptionally low. Consequently, despite the impressive skeletal remains showcased in museums globally, it is probable that the most enormous members of these species were even larger than those on show.
Dr. Jordan Mallon from the Canadian Museum of Nature stated, “Our findings indicate that for large fossil creatures like T. rex, we have no definitive understanding of the actual maximum sizes they might have achieved based solely on fossil records. Imagining a 15-tonne T. rex is intriguing, but it also raises significant biomechanical and ecological questions.”
