Asked by: Graham Roe, Lancashire
There are around a thousand different genera of dinosaurs known. We can’t directly measure the size of populations because we don’t know what percentage of individuals are preserved in the fossil record. Twenty million bison roamed America in the 18th Century and dinosaurs, being egg layers, could have reproduced faster. Assuming that the availability of plants was the limiting factor, large dinosaurs probably reached comparable population sizes in the Jurassic, 60 million years ago.