CLIMBING AND GLIDING
The canopy of the tropical rainforest is equivalent to a highway. And the various movements of different animals, are the different sorts of vehicles. There are those such as the gibbon, that make full use of their long arms to swing from tree to tree effortlessly, while those heavier ones prefer a much slower climbing motion. Others find climbing too troublesome and prefer a smoother and faster mode of travel, gliding. Whatever it is, they all serve the same purpose.
The use of tails as limbs
Rainforest animals have evolved to provide them with the best mode of travel. For some, the use of the tail as if it was another limb, has proved to be of great help. These tails are very strong and are able to support the weight of the animal. Evolution has rewired the nervous system of these animals that enable them to coordinate the movement of their tails. A list of the animals that make use of their tails for locomotion includes, opossums, some species of monkeys, pit viper snakes, and porcupines. These named animals uses their tail to anchor themselves on branches while they move or feed above the ground.
Similarly, a kinkajou can hold on to a tree with its prehensile, slender tail. Its tail serves as another paw to grip a tree tightly. Therefore, this monkey-like animal can hang upside down with its tail twined around the branch. This is especially useful when they are plucking fruits. It enables them to hold the food in one paw and break it by using the other. While running, the tail is used for balance. Besides, a kinkajou has the ability to turn its hind feet backwards. This allows it to scamper headfirst down a tree trunk without much difficulties.
Tarsier, like the name suggests, refers to the special position in the bone structure of the hind legs. The heel bones and the scaphoid (both are bones at the base of foot), tibia and fibula are joined together. This explains their amazing leaping abilities. As a vertical clinger and leaper, the tarsier has forward-seeing eyes that allows it to land safely. Being nocturnal, it sleeps during the day itself clung to slender trunks and its tail pressed firmly against the bark. This acts as a support. In addition, Celebes tarsier in particularly has bristles on the underside of the tail. In the other two species, a special skin structure is found on the tail. Nevertheless, slipping is minimized due to the effectiveness of the structure.
Found in the thickest vegetation is the potto. It is a slow climber that moves along a branch or liana smoothly and perfectly coordinated. While running along the branch, the potto has one hand and foot in contact with the support, always. Referred to as a grasping climber, its grip is very firm. Its thumbs and great toes can be extend very far and opposed to the other fingers or toes. Thus, it is able to grasp branches like a pair of tongs. This is especially made possible with the aid of strong hands and feet; in particularly the well-developed pads underneath these structures.
Sloth makes very little movement. And if it does, it is exceptionally slow. With the help of the curved claws of its four limbs, a sloth is able to hang on treetops and sway through the branches of trees in the rainforest. The shape of the claws enables it to grasp firmly on the branches and minimizes the chances of falling. They move from tree to tree with their belly up and their back down. In contrast, a sloth is extremely helpless on the ground. However, they are able to swim and are sometimes found crossing rivers.
The Emerald Tree Boa is one of the many snakes that climb into trees and bushes from time to time. Being short and stubby, it makes use of its prehensile tail to drape over branches most of the time. The tail serves as an anchor, in case the constrictor loses its grip. A further adaptation to an arboreal existence is the pair of ridges running along the body, near the edge of its ventral scales. This ridge provides additional grip and it exist mainly in certain species like the Yellow Ratsnake (Elaphe obsoleta quadrivittata). Its keeled belly scales allows it to negotiate the smooth trunk of a palm tree with ease.
Gliding
Gliding among animals is seen to be only common in the Asian tropical rainforest. Many animals there ascend up trees and glide either to the ground or to other trees nearby. The main mechanism behind gliding is to increase the body surface area. To do this, all the species of gliding animals have a flap of skin that is flattened and spread out. The wider the spread, the smoother the glide and the longer the time they spent in air. Gliding is not exclusive only to a group of animals; in fact gliding can be seen, among, snakes, lizards, frogs and mammals. The following at specific species, paradise flying snake (chrysopelea pelias), flying dragon (draco volans), flying gecko (ptychozoon kuhli), Wallaces flying frog (rhacophorus nigropalmatus) and Australian sugar glider (petaurus breviceps).
Like the Yellow Ratsnake, the Indo-Pacific flying snakes are able to climb smooth trunk of trees using their specially adapted belly scales. But when they move to another tree or when they are threatened, they launch themselves into the air from a maximum height of about 20m (66ft), sometimes higher. As this takes place, the rib cage expands such that the belly scales become concave and make wavy movements in the air. They are able to glide across distances of 10 m (33 ft) but always descend at a fast rate while doing so. Thus, flying snakes do not exactly fly but rather parachute downwards.
Another animal that glides is the flying lemur. The most prominent feature of these species is the patagium. It consists of three parts, namely the anterior, the flank membrane, and the tail membrane. By extending its arms and legs, the flying lemur is able to spread its patagium open and glide over distances of 50 to 70m (160 to 224 ft). The patagiuym acts as an airfoil, thus enabling the flying lemur to glide from one tree to another without having to touch the ground. Another special feature of the flying lemur is the sharp claws. They secure the landing of this mammal on vertical tree trunks, and enable it to leap upwards before starting on the next glide. Before it takes off, the flying lemur will climb to the top of its tree. It ascends by a series of clumsy rebounds, as it grasp the trunk with its outspread limbs. It stops at the top of the tree to choose its flight path. Then it launches to a long glide to another tree, landing low on the trunk, usually 3 to 4m (10 to 13 ft) above the ground. It will then climb slowly upwards along the tree, often pausing for rest. Once it reaches the top, it prepares to glide off again.
The Flying Squirrel too glides through the air. They can glide for about 50m (150 ft) at a time. And when they do, they always finish lower than from where they started. Therefore, a high starting point makes a long glide possible. Just like the flying lemur, their skin acts as a parachute and assists their movement. A fold of skin on each side of its body connects the front and back legs. When a flying squirrel stretches out its legs, the folds of skin spread out to form wings. Using its broad, flat tail to guide its flight, the flying squirrel glides from tree to tree. The squirrel's path is usually downward, subsequently straight, and finally upward. Giant flying squirrels can glide for distances of over 100m (300 ft).