These are the dinosaur bones of three members of the same species that were potentially roosting together. The diagram shows each individual dinosaur in the snuggle. (Photo: Gregory Funston/University of Alberta)
A block of fossils from the Mongolian desert not only contains three specimens of a new species of dinosaurs, but the fossils also show a new behavior among dinosaurs: snuggling.
Yes, it would appear that some dinosaurs enjoyed a good cuddlefest while napping, not unlike some animals, particularly birds, do today.
The block contained three juveniles of a new species of oviraptorids, a group of dinosaurs that have, "short faces, long necks and toothless beaks that lived during the Cretaceous period, 145 million to 65 million years ago," according to Nature. These fossils are a species that, as of August 2017, have yet to be named. However, they have a domed crest similar to the cassowary of today, and they walked on two legs.
The snuggling behavior exhibited by the dinosaurs is what caught researchers' eyes, however, including Gregory Funston, a vertebrate paleontologist at the University of Alberta.
"They would have been cuddling in life," Funston told Live Science. "This is a behavior known as communal roosting, where multiple animals of a single type sleep together overnight."
While one of the dinosaur's remains are only partially intact, the other two sets of fossils show the dinosaurs sitting down on the stomachs, with their necks curled back and heads cradled. Indeed, the entire arrangement "is quite similar to what ostriches and emus do when they get into deep sleep," Funston explained.
Scientists have found sleeping dinosaur remains before, but the fossils have only ever been by themselves, not in a group. And as Funston discusses in the video above, it's far more likely to find dinosaurs in a death pose, with their heads and tails tilted up, than it is to find them napping at their moment of death.
So what led these oviraptorids to curl up together in their final moments?
In animals today, this sort of roosting is done to control body temperature and to avoid predators. Funston speculated that the dinosaurs were likely huddling together for warmth, despite their size (it's estimated that each dinosaur weighed roughly 100 pounds). Frigid weather or a sandstorm could have been the cause for the dinosaurs to get their snuggle on.
Other researchers aren't completely convinced by this idea. John Grady, a biologist at Bryn Mawr College in Pennsylvania who has studied the metabolic rates of dinosaurs, suggested to Nature that young dinosaurs may have been huddled together to hide from predators, or that the spot was simply a nice place to sleep.
Funston disagrees since the dinosaurs would've been body-to-body in their moments before death, something that would've been rare to find in examples of animals today in the event of a flood or some other disaster that the creatures were seeking shelter from.
Regardless of the reasons, however, the fact that the oviraptorids were together at all seems to indicate that this species was a social one. While there's not enough evidence to fully support it, it's possible that these dinosaurs may have been related to one another, either as siblings or cousins.