Week 4 Blog Post: Comparitive Primate

Week 4 Blog Post: Comparative Primate

Lemurs are only found on the island of Madagascar. Madagascar seasons are dramatic and range from hot and rainy to a cooler dry season. Madagascar may have earth trimmers if one were central inland or cyclones in the west coast dependent on their location.
Due to the burning of forests trees in Madagascar by impoverished farmers seeking new farmland and wood to make charcoal for cooking the trees are sparse and forest is now open and rocky. The Lemurs are forced to spend more time on ground such as the Ring-tailed lemurs that spend most of their time on ground and have smooth, leathery palms and soles to accommodate for this evolved trait. The extremely seasonal environments have helped Lemurs evolve to cope and giving them a level of diversity that places them higher than all other primate groups. 

Sifakas live in larger groups of up to 9 animals. Females have a four to five month gestation period which produces one offspring.  The young holds onto the mother's belly when small, but then later is carried on her back. Babies are weaned after about six months and reach full maturity at the age of two to three years.

They have a variable social structure. They spend most of the day feeding, resting and social behaviors, such as playing and grooming, as well as traveling. Females occasionally take priority over males during feeding. Group members of all ages and both sexes will often groom, play, occasionally carry, and even nurse infants that are not their own. Like all lemurs, it relies strongly on scent for communication. Daily foraging is led by females and usually starts at dawn unless delayed by rain.
Locomotor patterns include climbing and leaping seen in Sifakas (propithecus) Lemurs. The jumping, which uses their long, powerful back legs allows them to launch themselves into the air and land in an upright posture on a nearby tree, with both hands and feet tightly gripping the trunk. Their legs are specifically adapted for this position since it is longer than their arms, and the big toe is especially long and strong for grasping. Some can leap up to 33 ft. jumping from tree to tree. When distances between trees are too large, Sifakas will head to the ground. Standing upright and hopping they move sideways with arms held to the side and waving up and down for balance.

Spider monkeys have been seen in the wild jumping from tree to tree. The Ateles hybridus (brown spider monkey) live in upper layers of tropical rainforests from central Mexico to central Bolivia. They are very social primates and live in brands of groups of up to 35 individuals. In early mornings, they arrange in smaller groups for Foraging. Spider monkeys spend most of their time in high branches and find food such as nuts, fruits, leaves and bird eggs. At night, they split up into smaller sleeping parties of a half dozen or fewer. Due to their large size, spider monkeys require large areas of moist evergreen forests, and prefer undisturbed rainforest. These New World primates can be noisy animals and often communicate with calls, screeches, barks, and other sounds.
Females give single births every two to five years. No one else besides the mother looks after the baby. Young monkeys depend completely on their mothers for about ten weeks. Mothers will care for their young for the first two years of its life, and often move about with their offspring clinging to their backs.
During the day, groups break up into subgroups of two to eight animals. The size of subgroups and the degree to which they avoid each other during the day depends on food competition and the risk of predation. Females rather than males disperse at puberty to join new groups. Males tend to stick together for their whole lives. Hence, males in a group are more likely to be related and have closer bonds than females. The strongest social bonds are formed between females and their young offspring.
In the wild, the spider monkeys are like acrobats and rarely come down to the jungle floor. They travel in small bands in forest trees, moving swiftly by making large leaps, sprawling out like spiders, and grasping tree limbs with their prehensile tail. They are fast and shape as they move through the trees with one arm strides. 
Their feet are greatly elongated and their big toe is prehensile (grasping), working like hands to grasp smaller branches. They have ability to walk upright on two legs on branches or even use its tail as a third limb. When the animal is on the lookout, it stands or walks on two feet, using the tail to hold on to a support. Their specialized tails may contribute to increased efficiency in travel, allowing them to cover larger distances using less energy.
Spider monkeys use several different types of locomotion:
·       Quadrupedal- all four limbs for locomotion as seen while walking or running.
·       Brachiating- used when hanging, climbing or moving through the trees. 
·       Bipedalism- using only two limbs when leaping.
They are adequately equipped for their strictly arboreal lifestyle with their slender bodies, disproportionately long limbs and a long prehensile tail which serves as a fifth hand. These adaptive traits allow them to move freely and efficiently. When a Spider monkey walks, its arms practically drag on the ground. Unlike many monkeys, they do not use their arms for balance when walking; instead they rely on their tails. The hands are long, narrow and hook-like. spider monkey's hands have four long fingers and an extremely small thumb, which is a special adaptation to their lifestyle. This is also probably why grooming is not as important to social interaction since they lack thumbs. These monkeys depend highly on their keen binocular vision.

Africa and southeastern Arabian Peninsula are home to many Baboons. Belonging to the Old World monkey family, hamadryas baboons live on plains and rocky hills of Saudi Arabia, Yemen, and eastern Africa near the Red Sea. Baboons are terrestrial (ground dwelling) and are found in open areas. They can raid human dwellings, and in South Africa they prey on sheep and goats.
Baboons live mostly on the ground but sleep in trees or cliffs. Baboons live in hierarchical groups of ranging from 10 to 200. A majority of the groups have more females than males. Groups are ruled by several large males. Some males will raid harems for females which are recruited while they are still too young to breed. Such situations often cause aggressive fights by the males. Some males are successful in taking a female from another's harem. In many species, infant baboons are taken by the males as hostages during fights.
Hamadryas baboons differ since they live in harems made up of one male and several females and their young. The males are fierce fighters and protect the group. Their group will typically include a younger male, but he will not attempt to mate with the females unless the older male is removed. In the harems of the Hamadryas baboons, the males jealously guard their females, to the point of grabbing and biting the females when they wander too far away. The hamadryas baboon is dependent on water, and is never found far from water sources. Their wild life expectancy is about 30 years.
The male hamadryas baboon is often twice the size of an average female. Another exception for the hamadryas species is that when the aging male lose their dominance they are allowed to remain as a part of their clan, instead of being separated as can be seen in most other baboon species.
Hamadryas Baboons are active during the day and they are mainly found on the ground. They move around on all four limbs (quadrupedally).They are terrestrial walking. Baboons are fast animals. They have long arms and strong legs, to help them outrun most enemies. Baboons are also excellent climbers. They have long tails, which help them keep their balance on branches. If a baboon can’t outrun an enemy, it will climb a tree. During the day, baboons can climb trees to avoid enemies, but at night they often climb high up to the sides of cliffs or treetops for protection from predators.
The forelimbs and hind limbs are long in relation to the trunk and almost equal in length to each other. They are generally kept straight during quadrupedalism. Hamadryas Baboons have a body weight of 26-46 lbs. which might be why they don’t move about in trees all day and only utilize trees for sleeping and protection from predators. They travel for longer distances and usually forage. They have an ability of swiftness which allows them to move safely and avoid predators such as Leopards, lions, and hyenas. These enemies and others live on the ground, since they hunt at night, baboons sleep in trees for safety. They have short tails and rough spots on their protruding buttocks which are nerveless, hairless pads of skin that provide for the sitting comfortably.

Gibbons live in tropical and subtropical rainforests from northeast India to Indonesia and China. Siamangs Gibbons are social animals and can grow to 29 lbs. They are strongly territorial, and defend their boundaries with visual and vocal displays. Gibbons are monogamous and live in family groups consisting of an adult pair and their young offspring. The family uses loud, haunting calls that can echo for miles to protect its territory.  Mated pairs, and even whole families, will sing together. Some species have even adapted large throat pouches to amplify their calls. They do not make sleeping nests, they sleep sitting up with their arms wrapped around their knees and their head tucked into their lap. Mothers usually have a single baby at a time; twins are rare. Female Siamangs care for their young babies. They are weaned at about 1 year old. Young Siamangs stay with their mother for about 5-7 years. After 7 years they venture out to start a new family group of their own.
Gibbons are masters of their primary mode of locomotion, swinging from branch to branch for as far as 50 ft., and speeds 34 mph. They can also make leaps of up to 26 ft., and walk biped ally with their arms raised for balance. They are the fastest and most agile of all tree-dwelling, non-flying mammals. They are known for injuries due broken branches or hand slips.
These mammals have adapted perfectly to life in the trees and rarely seek the ground. They have strong, hook-shaped hands for grasping branches. They have outsize arms for reaching faraway branches, and long, powerful legs for jumping. Their shoulder joints are even specially adapted to allow greater range of motion when swinging. They also walk on tree branches using only their legs. This way of walking resembles the way human beings walk on the ground. They throw their arms up in the air for balance. Unlike other gibbons, Siamangs have webbing between the 2nd and 3rd toes.

The gibbons' ball-and-socket joints allow them unmatched speed and accuracy when swinging through trees and reduced the energy needed in the upper arm and stress on the shoulder joints. But like all apes, gibbons evolved to become tailless. Sometimes when a gibbon is swinging, its wrist will naturally dislocate until the gibbon finishes its swing. Gibbons also have extremely long hands that are longer than legs. Their short thumb is set well down on the palm, and their fingers form a hook, which is used during tree swinging.

Chimpanzees live in tropical Africa.
Chimpanzees live mainly in humid rain forests or dry grassy areas with few trees. They range areas searching for food. They cover more land if there are fewer trees.
Chimpanzees are known for forming communities that travel in three types of groups;
·       All-male.
·       Mothers and their infants.
·       Mixed of both sexes, controlled by the dominant (alpha) male.
Chimpanzees spend a majority of the day in trees and are only on ground for about 25% of the day. They create new nests every night in trees for sleeping. 
After a 230 day pregnancy, female chimpanzees give birth to a single baby once every three or four years, which they will raise by themselves. The infants ride under the mother's body, until they are about 5 months old. Then they ride on the mother's back and leave their mothers after 6 years.
Adult chimpanzees enjoy the social activity of grooming where they pick through each other’s hair to remove dirt particles. They occasionally fight among themselves, usually to establish their rank within the social group. They are also aggressive toward chimpanzees from other territories and will sometimes kill them. The alpha male will need to intimidate other members in an attempt to hold on to power and maintain authority. Female chimpanzees also have a hierarchy which is influenced by the position of a female individual within a group for access to food. It is often the females who choose the alpha male. For a male chimpanzee to win the alpha status, he must gain acceptance from the females in the community.
Chimps have long arms, and when extended, they are about 1 ½ their body height. Their arms are longer than their legs. The bonobo is a little shorter and thinner than the common chimpanzee, but has longer limbs. Both species use their long, powerful arms for climbing in trees. Chimpanzees usually walk on all fours using their knuckles to support their bodies. Both the common chimpanzee and bonobo can walk upright on two legs when carrying objects with their hands and arms. The bonobo has proportionately longer upper limbs and tends to walk upright more often than the common chimpanzee. The face, fingers, palms of the hands, and soles of the feet are hairless. They do not have a tail.
Knuckle walking is a form of locomotion is due to the fact that chimpanzees have longer arms than legs.  So they walk using the soles of their feet and on the knuckles of their hands. Their feet are well suited for walking since the soles are broader and have shorter toes. Chimps have both opposable thumbs and opposable big toes which helps grip branches.

The environment has much effect on the primate’s physical traits leading to the tough skin on their bottoms to opposable thumbs and toes for flexibility. The evolution has adequately provided traits for each species based on their need for comfort, use, protection and speed. I can’t help but mention the main causes for extinction is due to human causes such as lodging, clearing, pet selling and hunted for food.