Was the giant Spinosaurus a terrifying land predator or a specialized aquatic swimmer?

Nature · Published 29 September 2026 Swipe more like this →

In short: Spinosaurus remains one of the most enigmatic dinosaurs ever discovered. Once thought to be a massive terrestrial carnivore, recent evidence suggests a semiaquatic lifestyle. From its mysterious sail to its paddle-like tail, this spine lizard continues to spark intense debate among paleontologists regarding its true size and behavior.

First described by Ernst Stromer in 1915 from Egyptian fossils, Spinosaurus has long been a subject of scientific intrigue. The original holotype was tragically destroyed during a 1944 British bombing raid on Munich, leaving researchers to rely on archives and fragmentary remains for decades. It was not until the 21st century that new discoveries in Morocco, particularly the subadult specimen FSAC-KK-11888, reignited the study of this theropod.

The defining feature of Spinosaurus is its dorsal structure, which consists of neural spines reaching at least 1.65 meters in height. While early theories proposed a thin, sail-like skin structure for thermoregulation or display, others have suggested a hump-like form similar to modern buffalo. The animal's anatomy is equally distinctive: it possessed a long, narrow skull reminiscent of a crocodilian, and a tail deepened by elongated neural spines and chevrons, forming a paddle-like shape that suggests an adaptation for swimming.

The extent of its aquatic capabilities remains highly contested. While some researchers argue that its high bone density and foot morphology—which resembles that of shorebirds—indicate a semiaquatic existence, others challenge these reconstructions. Recent studies have criticized earlier models for overestimating body proportions, suggesting that previous size estimates of 16 to 18 meters were inflated. Current estimates, such as those from a 2022 study, place the animal at a maximum length of 14 meters and a mass of 7.4 tonnes, significantly smaller than earlier, more sensationalized projections.

The classification of Spinosaurus is further complicated by the debate over its species. While S. aegyptiacus is the primary type species, the validity of others like S. maroccanus remains disputed, with many experts labeling them as dubious names or synonyms. Despite these controversies, the ongoing analysis of cranial material and skeletal models continues to refine our understanding of this unique predator, which thrived in the tidal flats and mangrove forests of North Africa approximately 100 to 94 million years ago.

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