A Prehistoric Social Network
On the shores of a shallow, ancient lake, giant flying reptiles gathered in great numbers. The Uhangri Formation in Haenam, South Korea, preserves a unique moment from the Late Cretaceous period, approximately 81 to 79 million years ago. This site is a collection of isolated fossils; it is the location of the world's first clear evidence for colonial nesting in pterosaurs. The discovery of eggs clustered together suggests these creatures, much like modern seabirds, were highly social animals that nested and likely raised their young in bustling communities.
The primary evidence comes from both the eggs and the astonishing array of fossilized footprints left in the soft lakeside sediment. Paleontologists have identified 443 pterosaur footprints, first excavated between 1996 and 1998. The most prominent trackways belong to an ichnogenus named Haenamichnus uhangriensis. These tracks were made by a large azhdarchid pterosaur, a type of toothless pterosaur with a long neck. Based on the size of the footprints—some pes (foot) prints are up to 350 millimeters long—scientists estimate the trackmaker stood about 3 meters tall and possessed a wingspan of up to 10 meters. One trackway stretches for 7.3 meters, the longest continuous pterosaur trackway ever found, demonstrating these animals were competent walkers on the ground.