Primates
INDEX
WHAT ARE PRIMATES?
TYPES OF PRIMATES
PRIMATE FEATURES
EVOLUTION OF PRIMATES
PRIMATES OF ARDASTRA
WHAT ARE PRIMATES?
Primates are a group of mammals that have five fingers and five toes equipped with “finger nails” and not claws, except for a couple of primitive examples. This group contains about 233 different species and also includes humans. Apart from humans, primates are only found in Central and South America, Africa, Asia and Madagascar.
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TYPES OF PRIMATES
Primates are broken down into three major groups; the prosimians (pre-monkey), monkeys and apes. Below is an example of how the primates are separated.
PRIMATE FEATURES
There are a number of features that most, if not all, primates have:
- Prehensile hands – enabling then to “grab” hold of branches or “hold” objects such as sticks etc.
- Five fingers and five toes – equipped with finger and toe nails instead of claws (true for all except the marmosets and tamarins which retained the primitive “claws” and even have a grooming claw.
- Large brain compared to body – most primates are extremely intelligent and insightful.
- Eyes located on the front of the face – providing binocular vision, which is good for judging distances, and this is essential for moving amongst tree branches.
- Omnivorous - eating both plants and animals, but mainly eat plants. Primates teeth tend to be blunted for grinding up nuts etc.
- Singular births – most primates have one young born at a time, some may have twins.
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PRIMATE EVOLUTION
The evolution of primates is an interesting story following a fascinating series of events.
Primates appeared shortly after mammals first evolved. These first “archaic” primates appeared in the geological records some 65 million years ago and were more squirrel-like in appearance; had claws for climbing and were more insectivorous, as were most mammals of that time.
During this time, flowering plants also went through many changes as they become less dependent on wind for pollination and seed dispersal and more dependent on insects. The flowering plants exploded in diversity, producing different types of fruits and flowers, which eventually gained attention from some of the mammals foraging amongst them.
The teeth of the archaic primates began to change from being sharp (insectivorous) to blunted (seed-eating) "omnivorous" teeth. It is at this time that the first prosimians appeared. They lost their claws and gained an opposable thumb, allowing them to “grab” branches and fruits or flowers. Their eyes moved to the front of the head, which gave them a better ability to navigate thru the trees. These early prosimians, as well as birds, were very important for the flowering plants for pollination and seed dispersal. With all of the new food resources available, the prosimians enjoyed a time of forests rich in food. Many different species emerged utilizing many different dietary niches.
Then about 20 million years later they began to slowly die out as temperatures began to drop and monkeys began to evolve; producing more competition and replacing them in many environments at that time. Compared to the prosimians, the monkeys had fewer teeth, less fox-like snouts, larger brains, and increasingly more forward-looking eyes. Today, lemurs are only found on the island of Madagascar and they managed to escape extinction as this island separated from Africa shortly after the monkeys evolved. African Prosimians (Bushbabies) managed to escape extinction by becoming nocturnal, where there is less competition.
New World monkeys appeared for the first time about 30 million years ago on South America, which was still isolated from North America at that time. It is generally thought that they began as isolated groups of old world monkeys that somehow drifted to South America either from North America or Africa on large clumps of vegetation and soil. Such "floating islands", produced as a result of powerful storms tearing at the land, still occur in tropical regions of the world today. This separation from the old world continent facilitated the differences that you see between old world and new world monkeys today.
About 20 million years ago, monkeys in Africa began to respond to changes in habitat. Grasslands slowly replaced forests in some areas and the monkeys began to spend more time on the ground and as a consequence, they lost their tails. These tail-less monkeys were the first apes; they had much larger brains and quite different facial features from the monkeys.
About 14 million years ago a group of apes in the savanna regions of southern Europe began to migrate south into Africa to avoid the ever-increasing cold weather in Europe. Then around 5-6 million years ago the first human-like ancestors began to emerge, breaking away from the chimps and bonobos. These are our direct ancestors.
PRIMATES OF ARDASTRA
Ardastra gardens has three different types of primates; Ring-tailed Lemurs, White-fronted Cappuchins, Schmidt's Guenon.
Ring-tailed Lemurs (Lemur catta)
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Endangered species
Lemurs are prosimians or "pre-monkeys" and are only found on the island of Madagascar and the Comoro islands off the South-east coast of Africa. The Ring-tailed Lemurs are best known for their long, black and white stripped tails and are often confused to be part of the raccoon family. These mainly diurnal (awake in the day), arboreal (tree dwelling) primates are well adapted to their preferred forested habitat. Having extremely long limbs, a long tail (for counter balancing), and leathery, padded soles for gripping branches, ring-tailed lemurs are excellent at climbing and leaping.
During the day, they spend much of their time basking in the sun or foraging for fruits, leaves, bark and flowers. Although ring-tailed lemurs are mainly frugivores (fruit eating) they will occasionally supplement their diet with other plant parts and insects. Despite being primarily diurnal and arboreal, these lemurs have been known to be active at night as they have excellent vision, and they are the most terrestrial of lemurs, by descending to the ground for food and movement.
These are social primates and form groups of up to 25 individuals with well defined territories. Females tend to dominate the troop and are responsible for territory defense. Vocal and olfactory (smell) signals are the most important ways for ring-tailed lemurs to communicate with each other. They have about 15 distinct vocalizations including clicks, grunts, squeals and howls. Anal gland secretions are used to mark out their territories. The ring-tailed lemurs also have glands on their forearms and in their armpits which secrete a fatty, odorous substance. They rub this substance on their tails which they wave in the air to signal antagonistic behavior.
White-fronted Capuchins (Cebus albifrons)
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Threatened species
These are new-world monkeys that are one of the six recognized species of capuchin monkeys. The White-fronted capuchins are one of the smallest of the capuchins. All capuchins are very lively creatures and are the smartest of all the small primates reportedly having the largest brains to body size ratio of all the new-world monkeys. In the wild they have been observed using sticks and other tools for various purposes. In the 1970's these monkeys were trained to assist in the care of quadriplegics (people who are paralyzed in both arms and both legs).
Like all new-world monkeys, capuchins are very arboreal (tree dwellers), equipped for life living in the trees. They have long limbs with an opposible big toe, allowing the capuchin to fully grasp branches with their feet as the maneuver through them.
These monkeys are diurnal (active in the day), foraging amongst the trees. The white-faced capuchins diet mainly consists of fruit with the occasional insect as well. Capuchins are highly social and spend most of their day grooming other members of their troop which can consist of about 15 - 35 members.
White-faced Capuchins are found in the rain forests of Northern South America, particularly: Bolivia, Brazil, Colombia, Ecuador, Guyana, Peru, Trinidad, Tobago and Venezuela. Though their populations in the wild are high, they are still considered a threatened species as their forest is constantly being cleared for farming and logging purposes.
Schmidt's Guenon (Cercopithecus ascanius schmidti)
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Threatened species
The Guenons are old-world monkeys that comprise the largest number of species for any African primate. This is attributed, in part, to the groups relatively recent evolution. Fossil evidence suggests that this group diverged from other African primate groups around 10 million years ago.
Guenons are some of the most colorful monkeys, the most distinctly colored of all being the Schmidt's Guenon. These guenons use their body color and certain gestures as part of their complex visual communication system.
The Schmidt's guenon has other common names demonstrating some of their distinctive features. They are often referred to as the Red-tailed monkey, due to their chestnut-red tail; or the White-cheeked guenon, referring to their puffy white cheek pouches, which are used to carry food while traveling.
These guenons are found in the Central African Republic, Kenya and Uganda; inhabiting lowland forest areas, swamp forest, and the forests surrounding rivers and dryer woodland. Like most guenons they are diurnal (active in the day), spending the day foraging mainly for fruit, some leaves, flowers and the occasional insect.
In the wild the Schmidt's guenon lives in small groups consisting of one male and up to about 5 females and their young. Although they tend to be unfriendly towards other groups of the same species, they will associate with other species of guenon and even other types of monkeys. Such associations are thought to occur due to the fact that the guenon's main predators are other monkeys, and so such alliances help to decrease predation.
Although the Schmidt's guenon populations are high in the wild they are still considered a threatened species as there is a major threat of habitat destruction due to the deforestation going on in many countries of Africa.
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