Paleontologists know very little about what the gigantic, bone-crushing T. rex looked like as an infant. The newly hatched fossils are so rare that they offer few clues about the behavior of these foot-tall carnivores. But now, tiny footprints found in rocks about 72 million years ago provide evidence that young tyrannosaurs traveled in pairs.
Paleontologists first discovered the tracks during a riparian survey of the St. Mary’s River Formation in southwestern Alberta. The site is littered with tracks left by many dinosaur species – “a busy time on the beach”, as Royal Tyrrell Museum researcher Donald Henderson and his colleagues describe it inside Canadian Journal of Geosciences. There are seven miniature dinosaur tracks in the fossil track, suggesting that the individuals moved in pairs. “The form of the small track, and the pace length, is perfect for something that hatches [tyrannosaurs] Albertosaurus either Gorgon’” Henderson said, noting that the sharp claw tips of the footprints suggested a predator.
Existing knowledge of Tyrannosaurus rex behavior comes mostly from bitten bones and some scarce footprints.Wounded skulls suggest T. rex fought by biting each other’s faces, footprints found in British Columbia suggest adults sometimes socialize together“T-rex wasn’t just a gluttonous, killing machine,” said fossil footprint expert Lisa Buckley, who was not involved in the new study. The newly discovered footprints suggest that hatchlings formed groups after leaving their nests, similar to some herbivorous dinosaurs — as well as living crocodiles and large ground birds.
The tracks could have come from different carnivore types, Buckley said, but either way, the discovery adds to the understanding of dinosaur life. “No matter which group of theropods was responsible,” she said, “the footprints in this paper are fascinating because they show evidence of group behavior.”
This article was originally published in Scientific American 327, 6, 17 (December 2022) with the title “Dino Buddies”