The early mammals that were present in this region during the time of Avimimus were the placental mammals Asioryctes nemegetensis and Barunlestes butleri, the amphibian Gobiates khermeentsavi, the multituberculate mammals Catopsbaatar catopsaloides, Chulsanbaatar vulgaris and Nemegtbaatar gobiensis, and the marsupial mammal Asiatherium reshetovi and Deltatheridium pretrituberculare.