T. rex Babies!
Have you ever wondered how small baby Tyrannosaurids like T. rex were? Thanks to some new research, paleontologists may now know their size and how they lived!
Trevor Schulz
7/9/20261 min read
Publication Info:
Transcript:
Longrich, et al. Hatchlings of Tyrannosaurus rex and the Evolution of Dinosaur Reproductive Strategies. Biology 2026, 15(13), 1090; doi:10.3390/biology15131090
Have you ever wondered how small baby Tyrannosaurids were? Thanks to some new research, paleontologists may now know their size and how they lived!
Episode 307
Notes:
So, there's baby T. rex news, and what's sad is you're probably going to find them cuter than their own parents did. So, baby dinosaur fossils are rare, and that's not surprising. Dinosaur fossils in general are rare, and the smaller they are, the more likely they are to get overlooked or missed or misplaced or misidentified or just never enter the fossil record in the first place because they get digested, which happens when you're a snack-size dinosaur. But, luckily, there are some specimens, including bones and teeth from T. rex and some of its close relatives. And to be clear, when I say babies, I do mean babies. These were hatchlings that were less than a year old. And baby T. rex were tiny, less than 5 lb or less than 0.1% of the adult body mass. That's the equivalent of a baby human being 2.4 oz or the weight of a big chicken egg. But, they made up for it by having massive egg clutches, with T. rex nests hosting 20 to 30 eggs, depending on the size of the parent, and their close relative Gorgosaurus reportedly having anywhere from 50 to 100 eggs in the nest. Baby tyrannosaurids are also born with pretty functional teeth. They are different from the adults, but they can do what they need to do. And their bones show significant density changes after hatching, really similar to the remodeling that paleontologists have found in baby titanosaurs. And all that evidence put together indicates that the young were extremely precocial, and the animals in general had had, to put it coldly, an r-selected reproductive strategy. Meaning that baby tyrannosaurs were pretty much on their own. I mean, ignoring the 20 to 100 siblings. As usual, if you want more information, here's the song.