Some dinosaurs slept in the same posture as birds

 

The posture of a new species of almost complete fossil dinosaur dug in Mongolia reveals that it curled up to sleep in a similar way of that of modern birds.

With the creature’s head tucked into her limbs and the tail comfortably wrapped around her body, her cosy posture resembled that of modern birds at rest, hinting that these dinosaurs not only looked like birds, but could also have behaved like them.

Paleontologists dug the dinosaurs skull and almost complete skeleton in the Gobi Desert, in the Goyo Barun Formation in Mongolia, and most of the bone were still arranged in the animal’s original death pose, which had to lose its life while sleeping, researchers reported in the journal PLOS ONE.

The animal’s long neck wrapped the right side of its trunk and its head was stuck to its side, leaning on the right knee. The rear limbs were bent underneath and most of the tail curved around the left side of the body.

The study authors identified him as an Alvarezsaurid, a type of small theropod (carnivorous bipedo adipine) with long tail and legs and short front limbs. Alvarezsauridos are part of a larger group of dinosaurs  called mainraptorans, which includes bird-like birds and dinosaurs that were their closest relatives.

The new fossil suggests that this sleeping behaviour may have been more common than expected among non-avian relatives of the first birds, the researchers reported.