The Evolution of Primate Locomotion and Body Configuration
Primates first evolved from the trees of tropical forests, later to the ground. Through the times of promisians to human, many characteristics has been represented due to the adaptations to new environments and resulted in evolutionary changes. The Earth has encountered several geological and climatic changes over time. For the primates existed at that time had to adjust itself especially in body configurations and locomotion in order to better survive. It is important to be aware of this information since we are the part of occurring changes as well. Throughout the evolution owing to the transforming environments interacting with natural selection, primates developed their own ways to move better (meaning changes in locomotion) with different types of bodies (meaning changes in body configuration).
Grade I – Lemuroids
Lemuroids, including true lemurs, lorises and galagos are the most primitive ones among the living primates. As they are the first grade of primates, they evolved in about 65 million years ago, in Paleocene epoch. Lemurs and lorises are the most primitive because they are more close to ancestral traits such as their reliance on olfaction, which enhances the sense of smell. Having dental comb, which formed by forward-projecting lower incisors and canines for feeding and grooming and grooming claw on the second toe are some distinguishable identities. Lemurs are only found on Madagascar and its adjacent islands. They vary in numerous species and ecological niches since they have no competition from monkeys and apes on the islands they live in. Lemurs range in size from the smallest mouse lemur with 5 inches to the indri with 2 to 3 feet (Nowak, 1999). The size of the lemur in comparison to other primates is an adaptation to the limited space on the island where it evolved (Jennifer, 2011). Locomotion of lemurs is diversified. Some are arboreal primarily and others are terrestrial like ring-tailed lemurs with their long, striped tails. It is common that some arboreal species are quadrupeds, and others (indris, ring-tails, and sifakas) are vertical clingers and leapers. Vertical clinging and leaping are the special characteristic of some lemurs and tarsiers. Lemurs are skillful climbers with strong hands and feet. Their hindlimbs are muscular to aid jumping from trees to trees. In midair to grab branches, they can twist their bodies at different angles. Since lemurs are adapted to climbing and jumping, many lemurs cannot walk up right. The sifaka lemur hops sideways on its back legs to overcome its inability to walk bipedally (Jennifer, 2011).
Lorises are mostly found in tropical forests and woodlands of India, Sri Lanka, Southeast Asia and Africa. They somehow resemble lemurs, but they survived in mainland by adapting to nocturnal activity. They are slow and careful which contributes to the challenges of their predators to find lorises. Their forelimbs and hindlimbs are more similar in length and they lack long tails. The tail, which looks like thick fur is variety of colors. They are arboreal and use slow quadrupedalism that enables them to climb the trees. They also have flexible joints that allow suspension by hindlimbs while the hands are used in feeding (Fleagle, 1999). The size can vary on the species, ages. Adult lorises usually are in size of 15 inches and weigh up to 4.4 pounds. Lorises have a powerful grasp that makes it difficult to remove them from branches, even though they are slow.
Galagos are in the same general category with lorises due to their exhibitions of good grasping, climbing abilities and visual apparatus. Also called bush baby which was created by their cries or appearance, they evolved in the forested and woodland savanna areas of sub-Saharan Africa. They range in size from the size of the mouse to a small cat. Unlike...