Elephas is one of two surviving genera in the order of elephants, Proboscidea. The genus has one surviving species, the Asian elephant Elephas maximus. Several extinct species have been identified as belonging to the genus, including Elephas recki, Elephas antiquus, and the dwarf elephants E. falconeri and E. cypriotes. The genus is very closely related to the mammoth genus Mammuthus. This animal appeared during Cenozoic era, the most recent era of geologic time, from about 65 million years ago to the present. The Cenozoic Era is characterized by the formation of modern continents and the diversification of mammals and plants. Grasses also evolved during the Cenozoic. The climate was warm and tropical toward the beginning of the era and cooled significantly in the second half, leading to several ice ages. Humans first appeared near the end of this era.