The gibbon in all its movements, and especially in those of its long arms, has a very singular appearance. In the second chapter of this work I have already described the geographical distribution and grouping of the species of these remarkable animals. Although they occasionally come down upon the ground, they are for the most part arboreal in their habits. They prefer the tropical forests of high and even of mountainous districts to any others. Many find shelter in the bamboo thickets, especially in those formed by the gigantic stems of _Bambusa macroculmis_ and _Bambusa gigantea_. The siamang, properly Si-Amang, since Rosenberg asserts that the first syllable is merely the article, lives gregariously in Sumatra, and possibly in Malacca. Martens saw one of these animals in Sumatra, swinging himself from tree to tree, right across the path, about fifty feet in front of him. Diard states that a powerful old male acts as leader to each troop. They raise a fearful clamour at sunrise, and keep quiet during the day, always on the watch, and scampering off at the slightest noise. They find it easy to get away on trees, but, according to some accounts, when surprised upon the ground, they show no agility, and are readily captured. Rosenberg says that in Sumatra the siamang and unko inhabit mountainous forests 3000 ft. above the sea, keeping to the trees which grow on the mountain-side, and rarely descending to the ground. At the slightest sign of danger they hasten down the mountain with speed which rivals the flight of birds, in order in a few moments to disappear in the dark ravines. In the forests which partly enclose Tobing, as well as on the mountains of Barissa, the siamang is not rare. Bock says that in the recesses of the Sumatran forests, this animal subsists chiefly on the leaves of a plant called _Daun simantung_. This ape makes a horrible roaring noise.[119] When a young one is wounded, its mother turns in a threatening manner towards the aggressor, yet without being able to do him any serious injury. The mothers seem to act with great tenderness towards their young, taking them down to the water to wash and dry them, etc. Diard affirms that before they are able to run alone the young animals are always carried by the parent of the same sex, the male by the father, the female by the mother. The siamang must fall an easy prey to tigers and panthers (_Felis macroscelis_). The species is considered by the natives to be slothful and unintelligent; and Bock adds that, although the Malays are skilled in the care of animals, they are unable to keep these stupid and slothful apes alive in captivity for any length of time.[120]