Pteranodon is a genus of pterosaur lived about 86 million years ago on the North America territory. The first fossils of flying reptile were recovered in 1870, in western Kansas by Yale University expedition. Interestingly enough that being the size of a large cat, its wingspan could reach 7 metres. Today only four type of Pteranodon species are known: P. Occidentalis (western), P. Ingens (the largest), P. Longiceps (the smallest) and Pteranodon sternbergi with vertical crest.

The unique feature of Pteranodon distinguished it from rhamphorhynchus and pterodactyl was its toothless. As such the feed included fish snapped out from the water in soaring flight. Moreover, Pteranodon males and females had long cranial crest. These crests consisted of skull bones projecting upward and backward from the skull.

The scientists suggested several theories regarding the crest function. One is that it was used for maneuvering in the air. It seemed to be true. However, females crest was directed upward while the males one - backward. It was also assumed that the crest did function as an effective aerodynamic counterbalance. Nevertheless, this theory was also disputed as the large crest of Pteranodon sternbergi had a negative effect on the head balance making flight difficult. The third theory included temperature regulation function but was also disputable as well because no extra vascular system was ever detected in the crest.