ing ▁and ▁parent al ▁care ▁ ▁Many ▁lines ▁of ▁foss il ▁evidence , ▁from ▁both ▁b one ▁b eds ▁and ▁track ways , ▁indicate ▁that ▁sau rop ods ▁were ▁gre g ari ous ▁animals ▁that ▁formed ▁her ds . ▁However , ▁the ▁make up ▁of ▁the ▁her ds ▁varied ▁between ▁species . ▁Some ▁b one ▁b eds , ▁for ▁example ▁a ▁site ▁from ▁the ▁Middle ▁Jur ass ic ▁of ▁Argentina , ▁appear ▁to ▁show ▁her ds ▁made ▁up ▁of ▁individuals ▁of ▁various ▁age ▁groups , ▁mixing ▁ju ven iles ▁and ▁adult s . ▁However , ▁a ▁number ▁of ▁other ▁foss il ▁sites ▁and ▁track ways ▁indicate ▁that ▁many ▁sau rop od ▁species ▁travel led ▁in ▁her ds ▁seg reg ated ▁by ▁age , ▁with ▁ju ven iles ▁forming ▁her ds ▁separate ▁from ▁adult s . ▁Such ▁seg reg ated ▁her ding ▁strateg ies ▁have ▁been ▁found ▁in ▁species ▁such ▁as ▁Al am osa urus , ▁Bell us aur us ▁and ▁some ▁di pl od oc ids . ▁ ▁In ▁a ▁review ▁of ▁the ▁evidence ▁for ▁various ▁her d ▁types , ▁My ers ▁and ▁F ior illo ▁attempted ▁to ▁explain ▁why ▁sau rop ods ▁appear ▁to ▁have ▁often ▁formed ▁seg reg ated ▁her ds . ▁Studies ▁of ▁micro scop ic ▁to oth ▁wear ▁show ▁that ▁ju ven ile ▁sau rop ods ▁had ▁di ets ▁that ▁differ ed ▁from ▁their ▁adult ▁counter parts , ▁so ▁her ding ▁together ▁would ▁not ▁have ▁been ▁as ▁product ive ▁as ▁her ding ▁separately , ▁where ▁individual ▁her d ▁members