The long necks of Plesiosaurus made them slightly cumbersome at speed, but they were not truly built for speed and such a feat was probably reserved for escape or short bursts from below prey. The large robust bodies and smallish flippers of Plesiosaurus itself is actually quite ill suited to speedy activity, as it certainly was higher in drag than later short necked plesiosaurs with aerodynamic bodies.However, the triangular head of the animals must have allowed for some aerodynamic capabilities. The large round eyes and nostrils, situated near the eyes and high in the skull, did not create too much drag either it appears. A shortened tail did not aid in mobility and, again, was most well suited to reduce drag as it did not directly aid in mobility of the animal. It did, certainly, aid in the stabilization of the animal as it swam, which the flippers did as well in addition to moving the animal through the water. Almost penguin-esque, Plesiosaurus must have been quite agile and beautiful as it swam, if not powerful or terribly interesting.