Fossil analysis suggests newly hatched tyrannosaurs were dog-sized

Probably the world’s most famous family of dinosaurs, the tyrannosaurs included the 40-ft (12-m) Tyrannosaurus rex within their ranks. Newly studied fossils now suggest that the reptiles were about “the size of a border collie” when first hatching from the egg.
The research was conducted by a team of scientists who are all affiliated with both Scotland’s University of Edinburgh and Canada’s University of Alberta.
They performed 3D scans of a 3-cm (1.2-in) section of jawbone from an embryonic Daspletosaurus tyrannosaur – found in Montana’s Two Medicine Format