Washington – Dinosaurs are commonly known from fossils. As such, it has become such a rigorous task to differentiate the males from the females. However, the different-shaped back plates on both male and female stegosaurs may help in distinguishing them.

Michal Benton, who is a paleontologist and was involved in this study, says that the armor they had on their back is the key to knowing whether a stegosaurus is a boy or a girl. The armor consisted of plates running down the middle of their backs either in a single or parallel strip. Some were found to be thin and wide while others were thick and taller.


Speculations have it that, fossils that had thin, wide plates were males while those with thick tall ones were female. Apparently, before then, the discovery of an egg or calcium on any would give the indication of the fossil being a female.

The largest known species of Stegosaurus reached about 30 feet (9.14m). However, Stegosaurus mjosi whose skeletons found in a Montana dinosaur “graveyard” and which is the species of the study measured roughly 21 feet.

Mr. Evan Saitta of Bristol University, UK, is quoted saying that males invest more into their ornamentation than females do. Hence, the larger wide plates are likely to have been from the male species. “The broad, thin structure of the plates plus their back positioning suggests that they were used in the sexual display.

Saitta, who is a paleontology graduate student, compared the skeletons of these fossils with those of other specimens. Computerized tomography (CT) scans and microscopic analyzes were performed to test whether the plate differences were from old or young individuals.

The results indicated a ceased growth of bone tissue hence this was evidence enough that the fossils were from full-grown adults.

Differences between the sexes of a single species as well as Anatomical are called sexual dimorphism. Many more Sexual dimorphism examples have been proposed, but scientists have argued that they are still inconclusive.

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