Nature has a video up with paleontologist Nizar Ibrahim, who discusses tailbones from the Sahara that indicate this gigantic, prehistoric bird relative swam for its supper:
A new fossil suggests that Spinosaurus aegyptiacus was a swimming predator powered by a fin-like tail, making it potentially unique amongst non-avian dinosaurs. The find comes after decades of debate on how much of its life Spinosaurus would have spent in the water, and how reliant they might have been on aquatic prey.