User:Eric Heldt/Arboreal locomotion

Diameter

Moving along narrow surfaces such as a branch of a tree can create special difficulties to animals who are not adapted to deal with balancing on small diameter substrates. During locomotion on the ground the location of the center of mass may swing from side to side. While during arboreal locomotion, this would result in the center of mass moving beyond the edge of the branch. Resulting in a tendency to topple over and fall. Not only do some arboreal animals have to be able to move on branches of varying diameter, but they also have to eat on these branches resulting in the need for the ability to balance while using their hands to feed themselves. This resulted in various types of grasping such as pedal grasping in order to clamp themselves onto small branches for better balance.

Incline

Branches are frequently oriented at an angle to gravity in arboreal habitats, including being vertical, which poses special problems. As an animal moves up an inclined branch, it must fight the force of gravity to raise its body, making the movement more difficult. To get past this difficulty many animals have to grasp the substrate with all four limbs and increase the frequency of their gait sequence. Conversely, as the animal descends, it must also fight gravity to control its descent and prevent falling. Descent can be particularly problematic for many animals, and highly arboreal species often have specialized methods for controlling their descent. One way animals prevent falling while descending is to increase the amount of contact their limbs are making with the substrate to increase friction and braking power.

Balance

Gibbons are very good brachiators because their elongated arms enable them to easily swing and grasp on to branches

Due to the height of many branches and the potentially disastrous consequences of a fall, balance is of primary importance to arboreal animals. On horizontal and gently sloped branches, the primary problem is tipping to the side due to the narrow base of support. The narrower the branch, the greater the difficulty in balancing a given animal faces. On steep and vertical branches, tipping becomes less of an issue, and pitching backwards or slipping downwards becomes the most likely failure. In this case, large-diameter branches pose a greater challenge since the animal cannot place its forelimbs closer to the center of the branch than its hindlimbs.

Crossing gaps

While some arboreal animals are living in their environment they need to be able to move from tree to tree in order to find food and shelter. To be able to get from tree to tree animals have evolved adaptations to help them jump the hurdle of going to different trees. In some areas trees are close together and can be crossed by simple Brachiation. While in other areas trees are not close together and animals have to have specific adaptations granting them the ability to jump far distances or glide.