|A black haired gibbon|
Gibbons are primates belonging to the taxonomic family Hylobatidae. There are four genera in this family, Hylobates, Hoolock, Nomascus, and Symphalangus, each with a varying number of species. Overall, there are approximately 14 species of gibbons. They are apes, like chimpanzees and gorillas, since they do not have a tail. They are aboreal, meaning that they live almost their entire lives in the trees, swinging around gathering food, and sleeping. The songs they belt out in the morning hours can clearly be heard from far away, and if you visit a zoo containing some of these fantastic animals, you can clearly hear their howls over all the rest.
The Gibbon is a mammal, and like all mammals, it is covered in hair, which can be light or dark brown, white, or black. They are entirely covered in hair, except for on their face, fingers, palms, armpits, and bottoms of their feet. They often have a ring of white hair surrounding their face. It has four fingers on each hand and opposable thumbs. These thumbs allow them to use their hands almost as dexteriously as humans. Their feet have five toes each, including an opposable big toe.  They have no tails, and are lightweight. They are actually very small, most of the males only reaching 3 feet in length, and 15 pounds in weight.
Gibbons are very acrobatic and agile. They have very dexterous limbs, and use their hands and arms to help them to swing though the trees. They are rarely on the ground, but when they are they can walk around on their hind legs. They can also use their legs to cross high branches, like a tightrope walker. They avoid large bodies of water whenever they can, because they cannot swim. They can also jump from tree branch to tree branch, and some have been known to make it over distances of 30 feet.
Nervous system and Senses:
Although their brains are less corrugated than humans, gibbon's nervous systems are just like human's nervous system. They have similar brains, spinal cords, and nerve layouts to humans.  Their senses are very similar to humans, including their touch, taste, smell, sight, and hearing.
Circulatory and Respiratory Systems:
The gibbon's circulatory system is pretty much the same as humans. Blood pumping from the heart to the body goes through the arteries, and blood going from the body to the heart goes through the veins. The heart works in this sequence- oxygenated blood from the lungs fill up the left atrium, it contracts, and drives the blood into the left ventricle. This then contracts and blood pressure inside shuts the mitral valve, making the blood go through the aortic valve to the aorta, bringing oxygenated blood to the whole body. While this is all going on, deoxygenated blood from the body tissues fill up the right atrium. This atrium then contracts, making blood pass through the tricuspid valve into the right ventricle, which also contracts. The remaining pressure closes the tricuspid valve and forces the blood out of the pulmonary artery to the lungs where the cycle starts all over again. The valves in the gibbon's heart work simultaneously.
Its respiratory system is similar to humans as well. The left lung is smaller then the right lung so it has more room for the heart. The left lung is divided into two main lobes, and the right is divided into three. Air enters through the gibbons nose or mouth. The air enters through the trachea, which divide into the right and left bronchi. Each bronchi enters into their respective lung. The bronchi divide into smaller bronchioles, which in turn divide into alveoli. The alveoli are round masses at the end of the bronchiole, and they consist of thin, flexible membranes containing a network of capillaries for the gas exchange. These capillaries separate gas from liquids and exchange CO2 for O2.
Gibbons copulate the same way as all mammals, and once they have select a mate, most of them stay together for life. Female gibbons stay pregnant for around 7 months, and usually have only one baby at a time; twins are rare. Baby gibbons are born hairless except for a small tuft of fur on the top of their head. They reach full maturity around 9 years old, and are able to reproduce around 12 or 13 years old. Female gibbons carefully care for their young, many of them for up to 6 years. Baby gibbons can grasp their mother's fur and cling to their mother's belly soon after their birth. After about one year, they become fully weaned. The young then leave their parents, or in some cases are forced out. They then eventually start new family groups of their own. 
In the wild, gibbons live in the rainforests of Southeast Asia. They are arboreal and are very rarely spend any amount of time on the ground. Spending less than 1% of their time on the ground keeps gibbons safe from most of their ground-dwelling predators. Gibbons spend their days moving around within the home range, alternating between foraging and resting. This ranging behavior occurs throughout the territory, especially near the edges, and as a result there are no designated areas for any certain activities within the home range. While foraging, gibbons follow single-file, with the female usually leading. The most important part of the gibbons habitat may be the trees they sleep in and that keep them safe in general.
Gibbons are the pickiest of all primates, and while they are omnivorous, they are mainly frugivores, meaning they eat fruit. They prefer fruit high in sugar, such as figs. They forage for food in the forests during the day, eating fruit, and they may visit over 16 different trees in a day's foraging. About three-fourths of their diet is fruit, but they also eat leaves, flowers, seeds, tree bark, and tender plant shoots. Sometimes they also eat insects, spiders, snails, bird eggs, and even small birds. When gibbons drink, they often do so by dipping a hand into the water, or rubbing a hand on wet leaves, and then licking the water from their fur. Gibbons sometimes do this while hanging above the water from a thin tree branch.
Some predators of gibbons include snakes, leopards, birds of prey, tigers, and even humans.  All of these animals kill the gibbons for food, and while humans do occasionally kill gibbons for their meat, they are at their most dangerous when they capture young gibbons to be sold as pets on the black market. However, gibbons are not entirely at the mercy of their predators. Scientists in Thailand observed that when faced with a predator, gibbons will actually move toward it and sing as loud as they can. Whether the song actually scares the predators away, or simply tells it that it has been spotted and the hunt is over, has not yet been determined. There has been speculation that gibbons use different songs for different predators, but this has not been confirmed. 
Gibbons don't construct sleeping nests. Instead, they choose specific trees that only their family may sleep in. They sleep sitting upright in the trees, huddled together in twos and threes, or they may choose to sleep alone. When sleeping alone, they wedge themselves into a fork in the tree branches. They keep their knees bent up to the chin, hands folded on the knees, and face buried between their knees and chest. This hunched over position conserves body heat. The gibbons also have special pads of tough skin on their hind ends that serve as cushions.
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- All about gibbons unknown