Dino Cliques

Three juvenile Triceratops, a species thought to be solitary, died together in a flood and now have been found in a 66 million-year-old bone bed in Montana. And that's reason enough for me to use the famed Far Side cartoon addressing how dinosaurs really became extinct.

Triceratops were ceratopsids (duh!), herbivorous dinosaurs that lived until the the very end of the Cretaceous Period. They have been found in enormous bone beds of multiple individuals, but all known Triceratops fossils up to now have been solitary individuals. The triceratops is one of the best-known of all dinosaurs, with more than 50 total specimens discovered, and until now it looked pretty certain to scientists that they were anti-social and avoided hanging out with their own kind.

This new discovery of a jumble of at least three juveniles in the famous Hell Creek Formation suggests that the three-horned Triceratops were social, or at least the juveniles were, revealing something about their behavior - a feature that is notoriously hard to discern from fossils. The news follows recent research that fossils of a bunch of juvenile ornithomimids were found hanging out in a group. Other researchers have found small herds of Psittacosaurus, a small cousin of Triceratops that lived in Asia.