 At the same time , tension began to build between Mantell and Richard Owen , an ambitious scientist with much better funding and society connections in the turbulent worlds of Reform Act – era British politics and science . Owen , a firm <unk> , opposed the early versions of evolutionary science ( " <unk> " ) then being debated and used what he would soon coin as dinosaurs as a weapon in this conflict . With the paper describing <unk> , he scaled down dinosaurs from lengths of over 61 metres ( 200 feet ) , determined that they were not simply giant lizards , and put forward that they were advanced and mammal @-@ like , characteristics given to them by God ; according to the understanding of the time , they could not have been " transmuted " from reptiles to mammal @-@ like creatures . 
