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T. rex babies were born ready to run and feed themselves
Phys.org • • science
Key Points:
- New research reveals that Tyrannosaurus rex hatchlings were surprisingly small, about the size of a house cat and weighing less than 5 pounds, contrary to expectations given the adult size of up to 9 tons.
- Analysis of tiny bones and teeth from museum collections, using high-resolution X-ray scans, showed that baby T. rex were already walking, running, and feeding themselves shortly after hatching.
- The study estimates hatchlings weighed around 1.7 kilograms (3.7 pounds) and measured roughly 75 centimeters (2.5 feet) long, with similar findings for the smaller Gorgosaurus species.
- Researchers suggest T. rex likely laid clutches of 15–30 eggs, indicating a reproductive strategy between that of modern reptiles, which lay many eggs with limited care, and birds, which lay fewer eggs with high parental investment.
- This work supports the idea that dinosaur parenting represented an evolutionary intermediate stage between reptiles and birds in terms of offspring care and development.
