Spinosaurus: The sail-backed, semi-aquatic fish-eater of Africa

Spinosaurus is one of the most unusual dinosaurs in the museum: it carried a huge sail on its back and probably spent much of its time in the water. It lived during the Late Cretaceous in North Africa and was a large semi-aquatic predator. The modern picture of Spinosaurus owes a great deal to a batch of remarkable fossils found in the last decade.

Its body

The striking sail on its back was supported by long spines, the longest reaching about 1.7 metres. The sail may have been used for display, for spreading out its body, or for controlling temperature — its exact purpose is still discussed. Its head was long and its mouth held conical teeth, well suited to gripping slippery prey such as fish. Its nostrils sat far back on the head, letting it breathe while partly submerged instead of lifting its head fully above the water.

Most surprisingly, its hind legs were relatively short, its claws were broad and its tail looked like a paddle. From these clues, scientists suggest it spent much of its life in North African rivers, wading and fishing like a giant heron. Whether it was a true "swimmer" or more a "wading fisher" is still being debated.

Where it lived and what it ate

Spinosaurus was a carnivore, feeding mainly on fish and possibly other water or riverside animals. It lived in warm, water-rich river systems and was one of that region's top predators, sharing the riverbanks with many other dinosaurs.

Where its fossils were found

Its fossils were found in North Africa, especially Morocco and Egypt. Because early finds were fragmentary, people's ideas about it stayed inaccurate for a long time; the new discoveries of 2014 and 2020 rewrote its image completely.

What the fossils tell us — and what they do not

Recent fossils give us a much clearer idea of its size, tail and limbs, but the purpose of the sail, the colour of its skin and the exact style of its swimming still depend on reconstruction and debate. So the Spinosaurus on the stage is the latest best answer from a field that keeps refining itself.

A note for grown-ups

You could talk with a child about how science changes: Spinosaurus's appearance has been rewritten by new fossils again and again. Showing a child that science is not a fixed answer but a process of getting closer to the truth is far more valuable than memorising one conclusion.