A new study has suggested that a cow-sized pre-reptile, living 260 million years ago, was probably the first animal to walk on all fours.
Known as Bunostegos akokanensis, this odd-looking herbivore walked like a cow and sported bony structures on its face.
In a study published by the Journal of Vertebrate Paleontology, researchers said the animal belonged to "a group of herbivorous reptiles that lived during the middle to late Permian in what is modern-day Europe, Asia, South America, and Africa."
Speaking to The Huffington Post US via email, lead author Morgan Turner said:
"Bunostegos is much further back on the evolutionary tree than anything else that exhibits this posture [and] hints at a larger story about posture and locomotion evolution... The anatomy of Bunostegos is unexpected, illuminating, and tells us we still have much to learn."
The team drew their conclusions from the animal's fossilised bones including the hip joint and fore limbs, that according to scientists, had features common to those found in upright animals.
Walking upright on all fours may have allowed Bunostegos to travel long distances--an ability that might have helped it survive the central desert of Pangea where it lived, Turner told The Huffington Post US.