The Evolution of Primate Locomotion and Body Configuration

Changes in body structure and locomotion are the most significant parts in the process of Primate Evolution. Evolution helps animals to adapt to their ever changing environment and take advantage of new resources and challenges arising with the changing environment.  By improving the structure of their bodies and the speed of movement Primates are able to withstand and escape their predators much easily and survive in the hostile environment. The changes in body structure are especially significant in primates for purposes of survival and existence.

The changes in body structure allow primates to develop greater chances of survival. Primates that evolve their brains, dental structures but do not evolve in body structure have low survival rates. Primates in the animal kingdom have variations in physical and behavioral characteristics that make evolution possible. They compete with each other fiercely for the limited resources available for their ability of survival. If a primates develops changes, the path of evolution it may have will also be affected .Evolution of the Primates is completely reliant on the environment and lifestyle of the primates.

Tarsiers  In the study of evolution tarsiers provide the least evidence of change and evolution. Because of their similarity to arthropods, their evolution history has normally been traced together. Their similarities generally rise from the structure of the placenta in the Tarsiers and arthropods. Their body structure however is often compared to that of Omomyids which most experts consider to be more closely related to the Tarsius, (Anapol, German and Jablonski 2004, 284).  Paleontologists have often compared the Tarsier ancestors, the Omomyids to the present structure of Tarsiers. Fossil records which can be used to authenticate the findings are still not having conclusive evidence.
Tarsier species was found mostly in the South Eastern Asia forests. Centuries back the Tarsier was frequently hunted by nocturnal predators and giant serpents. At the time the tarsiers were much brighter in color making them easily vulnerable. The fossil records also show a much more elongated body structure with the least length recorded being 20cms. The length of the tarsier is considered to have made it more susceptible to predators especially during resting periods. It could not move swiftly to evade attacks. Over time the Tarsier began folding itself to hide from predators. The act of folding itself resulted in the cervical vertebrae to bent become shorter. This in turn reduced the length of the tarsier to what it is currently. The tarsier measures a mere 13cm and is often difficult to spot when it hides in the bushes.

The study of the bones and muscle tissues from the fossils indicates that during the Eocene period, the Tarsiers were much more mobile. The branches in the trees were much shorter and therefore to protect themselves, the Tarsiers moved a lot swinging from one tree to another. The movements were often quick and fast, but because of the distance between hiding places the animals were often easily spotted and attacked by predators. The Tarsiers developed a much better technique which included folding their bodies closer to the trees and remaining motionless for hours. This made them invisible. Over the centurys successive generations of Tarsiers developed strong arm muscles that allowed them to hide within bushes and remain motionless for hours without getting tired.

The ability to hide in tree branches or crevices unmoving for very long periods has featured greatly in the tarsiers survival over time. Predators were unable to see the Tarsiers unless when illuminated with strong light.  

However Tarsiers are not as slow as one might expect. Tarsier only develops a slow nature to fool its predators. By predicting that the tarsiers are slow from their lazy outlook makes predators to attack them openly and with much less force and speed making it an advantage to the Tarsiers in surviving. The tarsier can however move very fast between branches. Though they developed strong arm muscles, they also maintained their strong hind muscles. Their small body structure also allows the tarsiers to hide easily from predators. Tarsiers can attack its predator in seconds, they are very swift. Their muscle structure gives them a strong body physique. Paleontologists believe that in the late evolution period tarsiers used to attack their predators by scratching. However because most of the predators had thick fur, the animal then developed muscle strength that allowed them to throw the attacker off balance.

Female tarsiers especially have developed a heightened sense of awareness and the ability to attack predators much larger than them in an effort to protect their young. By throwing their predators off balance using their body mass, the mother and her young are able to scamper off to safety mostly in small crevices where birds and other large predators cannot fit.
Tarsiers also have a cranial structure that allows them to turn their heads 1800 C. The rotation of their head arises from their low sensatory nature. It is hard for tarsiers to smell or sense danger. Tarsiers are considered to be low in intelligence capacity (IQ) and animal sensory ability, for this reason they have developed the ability to turn their heads completely. Tarsiers also have very low vision mostly average 1212 vision eyesight. This means that they cannot easily see predators attacking them from behind, however with their ability to turn full 180 degrees tarsiers find it easy to watch their backs despite their limitations of sensory organs. 

The sclater blue eyed lemur is one of the endangered species classified as lemuroids. Although Lemuroid has adapted to stay away from predators and increase its survival rate, the adaptations have not been fast enough to save it from endangerment. Lemuroid is mostly endangered by predators after the soft meat of the lemurs especially their young and traders who often deal in the illegal trade of the animals, (Fleagle 1999, Pg 558).

Lemuroids have exhibited changes over the years that have helped in their survival. In the early evolution periods lemuroids had a bent structure. The spine was horizontal in nature. They relied on both hands and feet to walk although they were slow in nature. They could not carry food and escape from predators at the same time. In later centuries, a class of Lemurs began to stand trying to reach higher branches and access better food. Over time the spine transformed to allow the vertical mobility. Lemurs are the only primates with a flexible vertebral column and they are very flexible in nature.

The main reason given by paleontologists for the development of flexibility is the competition for food and fear of predators. Lemurs were often in danger while gathering food from predators trying to attack them. As an adaptation lemurs developed the ability to stand straight and run on their hind legs when in danger. Because of the need to jump from one branch to another easily lemurs developed the ability to use all limbs for movement.

Lemurs have developed strong muscles that make it easy for the animals to leap from one branch to the other. The lemurs are leapers who can jump across long distances supported by their hind legs. They develop the skill when they are young and often perfect it before adulthood. The young Lemurs often cannot leap long distances the parents take time to teach their young this exercise.
From fossil records scientists have gathered that the lemurs were previously leapers but not very good ones. The limb muscles tended to wear off before adulthood and the animal often got very tired escaping from predators. Through the development of much more elongated bone muscle tissues in the hind legs a minimum of 2.5cms, the lemurs are able to run much faster, and with their elongated hands often measuring to an average of one and a half meters they can jump easily and fast from one branch to another without loosing their grip.

The experts have recorded that interestingly that the lemur escapes from it predators both humans and other animals, including eagles who often hunt their young ones, by dropping suddenly from trees and running at and amazingly fast speed to the bushes. Predators are often unable to adjust their vision before the lemur has scampered off to safety, (Harcourt, Thornback and IUCN 1990, Pgs 194).

Fossil records estimated from about five million years ago show the Lemur ancestors with much shorter and thicker hands. The phalanges were much shorter almost half an inch shorter. The Lemurs could not carry a lot of food. They also had a much weaker grip which made leaping difficult. Because of stretching their hands during leaping and to carry a load of food, Lemurs especially the females developed longer phalanges. When the Lemurs cup or fold their hands they usually have much more space than in other species. Paleontologists claim that some of the lemurs such as the Blue eyed Sclater can fit food that would otherwise fit into a small egg basket on their palms.

Monkeys are perhaps the most featured species in the evolution theory. They have developed and adopted different environments in several ways. Monkeys are rumored to have come in existence way back from the
Eocene period. Fossils records often indicate that Africa is the cradle of Monkeys evolution and their existence.

The fossils of monkeys were first spotted along the Zaire River, where the main threat to their survival was the competition with chimpanzees for food. Over time Bonobos developed very strong leg muscles, which unlike popular belief were not initially meant for movement but more for fighting off the stronger chimpanzee.

The monkeys have great muscle strength that can easily drop a predator. The monkeys themselves are small in nature but the strength of their muscles is almost unequaled. In later generations the muscles came to be relied upon for fast movement, (Bolhuis and Giraldeau 2005 Pgs 16).

The monkey has developed long hand and legs which he uses for movements. The long hands allow the monkey to swing easily from branch to branch while the long legs allow the monkey to move faster than the average running speed of monkeys. In the forest biome the monkey was often at risk from small carnivorous animals that could move very fast. There was also the tendency to lose their food to small animals that often stole from them. The monkeys developed speed as a way of protecting themselves and their stash of food. Monkeys can often move much faster than most predators in the forest. Their hind muscles have increased in length over time to more than 1meter.

The monkeys general body elongation has increased with time. The elongation of the spine has lengthened the body to at least more than 2 feet. The elongations of the body allow monkeys to leap further distances than any other primate. This ability developed not more than 2million years ago, when the forest biome gained so many competitors and inhabitants. The ability to jump from far off branches gave the monkeys the advantage of better quality food.

The Monkey has also developed the most unique tail that is quite long and strong. The nature of the tail is such that it has stronger muscles than in any other primate. The monkeys have often been seen using the tail not just for leaping but also protection. The tail holds the weight of the monkey when he wants to reach higher branches and also acts as a limb so the monkey can carry food with both arms and still swing from branch to branch, (Minnelli 2009, Pgs 220-223).

Over time the Monkeys tail also developed a furry end that is often used to distract a predator when they are attacking. While predators may be on watch for the movement of hands and feet, they rarely observe the tails which often move very fast and their strong muscles coupled with the furry ends can knock off any opponent.

Apes and Human beings
Paleontologists often relate human being evolution and that of apes. It is often considered that apes were the ancestors of human beings. The body elongation of both ape and man was much shorter, and their width much thinner. The apes walked on all fours to support their great weight. The ape fingers could not hold anything as they were joint phalanges from which things slipped easily.

The desire to hold equipment and tools differentiated the evolution of man and that of apes. The apes developed much thicker bodies and muscle tissues. Apes are much heavier than normal primates often weighing 200kgs and above. They have very thick muscle tissues for protection in the cold weather. Apes are thick in fur, with long multicolored hairs. The fur thickness develops from their cold terrain which they normally inhabit.

On the other hand from the time of Homoerectus and Neanderthal man, human beings began developing elongated spines. Their structure began changing putting more focus on their feet to hold the body mass which reduced greatly from 250kgs to lowest than 100kgs. Their hands also developed separates and elongated phalanges used to hold tools and other equipment.
In the early Pleistocene era, the Homohabilis developed a much bigger brain that eventually led him to discover fire. With this discovery, human beings began to shed the fur that had long adorned and kept them warm.

In the late Pleistocene both apes and man had much shorter tails and eventually proceeded to do away with the tail. In the hunting and gathering trade, the tail was often considered to give an advantage to predators. Paleontologists actually believe that both man and ape began cutting off the tails of their young eventually leading to a generation that had significantly shorter tails which completely disappeared in the coming generations.

Literature Review
The information on the evolution of primates is widely available. The argument that by improving their body structure and locomotion speed, primates find it easier to survive is well presented and verified. Over time primates have restructured their bodies to ensure much more chances of survival. In the Oligocene period the population of monkeys decreased radically following the increased numbers of predator. Changes in their muscle strength and speed of movement ensured the increase in the population during the Miocene period as evidenced by the high number of fossils recorded from that period.

The information on the evolution of tarsiers and lemurs is much more difficult to access. The fossil records are easily available. In fact very few fossil records on tarsiers and lemurs are available today.  However a study conducted by paleontologists show that Tarsiers originally in south East Asia began migrating and increasing in population as soon as they begun changing.

The literature on man and apes is far much more extensive. The changes that occurred in man have saved him from extinction. Though no recent evolution changes have been recorded, the fossils found in Kariandusi in Africa and in Asia show how much man and ape have evolved. The ancient fossils provide evidence of the changes in both species.

Experiences and Observations at the LA zoo
The LA zoo visit proved to be interesting and educational for me.  The visit was quite memorable for me since it was my first in the United States. My first stop was the Japanese garden where I was able to view the chimpanzees who were very playful, swinging with bars and branches, generally having a great time. 
Perhaps even more interesting than their playful nature was their nurturing behavior. The chimps are very similar to human beings often tending to their young ones with great care. The mothers never really left their childrens side. The effort put in by the mothers to ensure the comfortability and protection of their young reminded me so much of human beings and the similarities among the primates and humans.

The most fascinated fact was all the mother mammals were so full with love for their babies. Especially primates chimps monkeys, and gorilla were very similar to the human beings. It is true that all the mammals take care of their offspring until when they grow to be able to feed and survive independently. But the fascinating aspect was looking at those monkeys, gorillas, and chimps taking care of their babies reminded me the real human affection and connection.  I knew they are very intelligent creatures and in certain point they are very similar to humans not only their  body or genetic code  which is similar as monkeys are physical 98 humans resemblance ,they could also use tools, grasping the food with hands, and occasionally walking with two legs. The first hand experience of observing the primates closely was different and special although I had known them through reading books and research. Later I found out one of monkey that I saw, kikyuyu Colobus monkey, was just born in November 27, 2009 during research for this paper. It was a perfect coincidence.

Challenges experienced  on the day I visited the zoo some of the primate exhibits had been closed to the public. Instead of the 20 exhibits I had expected to view, I only succeeded in viewing 12.
Secondly, there were plenty of unruly and noisy children, who continuously banged on the cages agitating the animals and frightening them. It seems that the zoo has no policy against such behavior.
Finally, because of the heat present on that day, many of the primates were either asleep or hiding in shades. Hardly any animals were involved in play and activities except for the chimps.

My paper has ultimately proved that evolution of primates centering on body structure and locomotion gives them better advantage in the competition for meager resources. There are some primates that have increased in elongation such as monkeys and others have evolved with much shorter lengths such as tarsiers. I have come to the conclusion that in the end such evolution traits have given the animals a better chance to survive. Primate species that have not evolved like improving their body structure and locomotion ability faced extinction. Much of the locomotion evolutionary changes seem to arise from the need to escape predators by possessing either stronger muscles for running or limbs for leaping.

In conclusion therefore, the development of body structures and locomotion abilities in primates over time has ensured the survival of some species. The resources are continuing to become scarce and fewer especially with the diminishing forest biomes. The competition for food and space has also increased. There is need for the Primates and human beings at some extent to develop more adaptable body structures to survive the changes. Those species that do not improve the structure of their bodies and the locomotion speed would find it impossible to adapt to the dynamic environment.


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