Venomous mammals: A review

► Venomous mammals are known by folklore and their study is just beginning. ► Insectivora, Monotremata, and Chiroptera have mammalian venomous species. ► Mammalian venoms are different in their biochemistry and modes of action. ► New fossil evidence suggests that primitive mammals were venomous. ► Less-studied venoms, as the mammalian ones, are promising as therapeutic agents.