Dinosaurs came in all shapes and sizes, some with spikes and spines on their backs (such as Ankylosaurus), some with large plates (like Stegosaurus) and a few with large fins or sails. Dinosaurs with sails are thought to have had spines emerging from their vertebrae, which were connected by a membrane. This is currently thought to have been for mating displays, possibly being vibrantly coloured to help the animals attract a mate or compete with others for mates or territory. They may also have helped individuals tell each other apart. 

Whatever the true reason for these magnificent fins, they belonged to only a select few dinosaurs and some pelycosaurs - mammal-like reptiles that lived before the dinosaurs. Here, we take a look at some of the notable dinos that sported sails or fins. 

Spinosaurus

Spinosaurus is perhaps the most famous finned dinosaur. It lived in the Late Cretaceous  (99 - 94 million years ago) and was a large, meat-eating creature. Scientists think it was semi-aquatic, meaning it spent lots of time living in and around water. It had a wide, paddle-like tail and an impressive sail that was about 1.5 metres high. Some scientists have speculated that this sail helped Spinosaurus to swim through the water, as well as being used for mating displays. 

Acrocanthosaurus

The name Acrocanthosaurus means ‘high-spined lizard ', and refers to the long spines that protruded from this dino’s vertebrae. It had a prominent sail that ran along its neck and back, which reached up to 30cm high in places. Unlike Spinosaurus, Acrocanthosaurus walked on two legs and is thought to have lived on land, preying on large plant-eating dinosaurs. 

Suchomimus

Roaming modern-day Niger in the Early Cretaceous (121 - 112 million years ago), Suchomimus was similar to Spinosaurus, with a crocodile-like skull and lots of finely serrated teeth. Like Spinosaurus, it is thought to have been semi-aquatic, living and hunting around shallow water. However, it couldn’t fully submerge as its bones were too light.  Its sail reached around 60cm high.

Concavenator

This meat-eating dinosaur was smaller than many other sailed dinosaurs, reaching only six metres in length. It lived in Spain in the Early Cretaceous (around 130 - 125 million years ago) and had two tall bones in its spine that created a crest near its hips. Scientists are unsure what this crest or small sail was for, as fossil evidence for the dinosaur is very limited. 

Ouranosaurus

Unlike many other finned dinosaurs, Ouranosaurus was a plant-eating creature. Like Suchomimus, it lived in the Early Cretaceous in what is now Niger in West Africa, perhaps sometimes crossing paths with the semi-aquatic dino. Its sail ran along most of its back and part of its tail, and was over 60cm high, possibly helping to make it look larger when faced with predators. 

Meet the dinosaurs at Dinosaur World Live

If you’re looking for a dinosaur adventure live on stage, don’t miss Dinosaur World Live. This award-winning family theatre show introduces kids to a range of prehistoric creatures from favourites such as Triceratops to lesser known beasts like Segnosaurus. The 2026 Dinosaur World UK tour starts in July, so search ‘dinosaur event near me’ and book tickets at your local venue.