Ọ̀ bụ na Pacific nwere? N'iburu ajụjụ nke mbụ n'uche, dee ihe gbara ya gburugburu bụ́ nke ga-enye azịza ya. Ọ nwere ike ịbụ 1 - 20 ahịrịokwu. Ihe ndị gbara ya gburugburu:
N'etiti Eocene, a na-ekwere na e kewara ebe mmiri na-asọba n'osimiri Amazon n'etiti kọntinent ahụ site na Purus Arch. Mmiri nke dị n'akụkụ ebe ọwụwa anyanwụ na-asọba n'Oké Osimiri Atlantic, ebe nke dị n'akụkụ ebe ọdịda anyanwụ na-asọba n'Oké Osimiri Pacific site n'akụkụ Osimiri Amazon. Otú ọ dị, ka Ugwu Andes nọ na-arị elu, e nwere nnukwu ndagwurugwu nke gbara ọdọ mmiri gburugburu; a maara ya ugbu a dị ka ndagwurugwu Solimões. N'ime nde afọ 5 ruo 10 gara aga, mmiri a na-agbakọta agbakọta gafere Purus Arch, na-esonye n'akụkụ ọwụwa anyanwụ na-asọba n'Oké Osimiri Atlantic.