The African bush elephant has grey skin with scanty hairs. Its large ears cover the whole shoulder and can grow as large as 2 m × 1.5 m (6 ft 7 in × 4 ft 11 in). Its large ears help to reduce body heat; flapping them creates air currents and exposes large blood vessels on the inner sides to increase heat loss during hot weather. The African bush elephant's ears are pointed and triangular-shaped. Its occipital plane slopes forward. Its back is shaped markedly concave. Its sturdy tusks are curved out and point forward. The trunk is a prehensile extension of the upper lip and nose. Short tactile hair grows on the trunk, which has two finger-like processes on the tip. This highly sensitive organ is innervated primarily by the trigeminal nerve and is thought to be manipulated by about 40,000-60,000 muscles. Because of this muscular structure, the trunk is so strong that elephants can use it for lifting about 3% of their own body weight. They use it for smelling, touching, feeding, drinking, dusting, sound production, loading, defending, and attacking. Both sexes have tusks, which erupt when they are 1-3 years old and grow throughout life. Tusks grow from deciduous teeth known as tushes that develop in the upper jaw and consist of a crown, root, and pulpal cavity, which are completely formed soon after birth. Tushes reach a length of 5 cm (2.0 in). The tusks of males grow faster than the tusks of females.
