The Asian elephant, Elephas maximus , is easily distinguished from its African cousin Loxodonta africana , because its ears are much smaller and its back slightly rounded or flat, unlike the concave saddle back of the African species. The trunk combines nose and upper lip and enables an elephant to breathe, locate scents, drink, and to seize and manipulate objects with extreme sensitivity. It is used both for gentle caresses and admonitory slaps at its young. Unlike the African elephant, only male Asian elephants have tusks. Some male Asian elephants do not grow tusks, but these tuskless males, known as makhnas or seedors , are often bigger than their tusked fellows are.
Tusks are actually giant incisor teeth, which grow throughout the elephant's life.
The longest recorded pair, which is held in Bangkok, is of 3m and 2.74m each. Smell is the most highly developed sense in elephants. They can pick up surrounding scents on the breeze, and they constantly feel and smell each other with their trunks. Eyesight is limited, but hearing is acute. Although known for their loud trumpeting, it was discovered recently that elephants also communicate with subsonic rumbles which can travel up to five kilometers.