As famous and popular as they are, we know very little about stegosaur biology. Infant stegosaurs are known from a few extremely fragmentary remains, and eggs are practically, if not totally, unknown. However, a recent discovery (thanks to CT scanning) made by Evan Saitta, a senior at Princeton, has revealed that there is a surefire way to differentiate between male and female stegosaurs: by looking at their plates.
|A male-female pair of stegosaurs in repose. Another male lingers in the background. Illustration by Connor Ross.|
So, how does one tell the difference between male and female stegosaurs by solely examining fossils? It turns out that one gender sported broader, more ovoid plates than the other, which carried more taller, more slender plates. Which plates belong to which gender remains to be seen, but I wouldn't be surprised if the males had the wider, larger plates than the females. When it comes to sexual selection, this is generally the case; males sport larger and flashier features than females.
While other uses for stegosaur plates, including thermoregulation, have not been ruled out, and still may be very likely, but confirming at least one suspicion about the still-very-mysterious biology of stegosaurs is one step in the right direction to uncovering just how these animals lived.