The majority of reports and discussions about Protosuchus appear to have a general consensus about the fact that the tail of this fossil appears to have many, and large, muscle attachments. The speculation about this suite of muscle attachments and the general shape of the tail has, in some circles of debate, given rise to the hypothesis that use of the tail as the main source of power in swimming for crocodilians originated in this genus. Locomotion via horizontal power strokes of the tail is a very visible character of extant crocodilians. Thinking of this high strutting cursorial predator as a strong swimmer is not beyond the scope of its anatomy, but combined threats by Protosuchus on land and in the water makes this animal far deadlier and a nearly universal predator. It is too bad there are not many images of it swimming though. John Sibbick made a composite of many different crocodilians that has Protosuchus near the water. The image here is by the late Zdenek Burian and depicts a shore dwelling Protosuchus looking rather mean-spirited, as 1960's dinosaurs and other fossil creatures tended to do.