▁In ▁a ▁series ▁of ▁scientific ▁papers , ▁books , ▁and ▁popular ▁articles ▁in ▁the ▁ 1 9 7 0 s ▁and ▁ 1 9 8 0 s , ▁beginning ▁with ▁his ▁ 1 9 6 8 ▁paper ▁The ▁superior ity ▁of ▁din osa urs , ▁Robert ▁Bak ker ▁argued ▁str enu ously ▁that ▁din osa urs ▁were ▁warm - blo oded ▁and ▁active ▁animals , ▁capable ▁of ▁sust ained ▁periods ▁of ▁high ▁activity . ▁In ▁most ▁of ▁his ▁writ ings ▁Bak ker ▁fr amed ▁his ▁arguments ▁as ▁new ▁evidence ▁leading ▁to ▁a ▁rev ival ▁of ▁ideas ▁popular ▁in ▁the ▁late ▁ 1 9 th ▁century , ▁frequently ▁referring ▁to ▁an ▁on going ▁din osa ur ▁r ena issance . ▁He ▁used ▁a ▁variety ▁of ▁an atom ical ▁and ▁statistical ▁arguments ▁to ▁defend ▁his ▁case , ▁the ▁method ology ▁of ▁which ▁was ▁fier c ely ▁deb ated ▁among ▁scient ists . ▁ ▁These ▁deb ates ▁spark ed ▁interest ▁in ▁new ▁methods ▁for ▁as certain ing ▁the ▁p ala e obi ology ▁of ▁ext inct ▁animals , ▁such ▁as ▁b one ▁hist ology , ▁which ▁have ▁been ▁successfully ▁applied ▁to ▁determ ining ▁the ▁growth - r ates ▁of ▁many ▁din osa urs . ▁ ▁Today , ▁it ▁is ▁generally ▁thought ▁that ▁many ▁or ▁perhaps ▁all ▁din osa urs ▁had ▁higher ▁met abol ic ▁rates ▁than ▁living ▁re pt iles , ▁but ▁also ▁that ▁the ▁situation ▁is ▁more ▁complex ▁and ▁varied ▁than ▁Bak ker ▁originally ▁proposed . ▁For ▁example , ▁while ▁smaller ▁din osa urs ▁may