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Archive for the ‘Monkey’ Category

monkeys: Night monkey | Douroucouli

07 Apr

Night Monkey

Night Monkey

Douroucouli

The Night monkeys, also known as the Owl monkeys or Douroucoulis, are the members of the genus Aotus of New World monkeys (monotypic in family Aotidae). They are widely distributed in the forests of Central and South America, from Panama south to Paraguay and northern Argentina. The species that live at higher elevations tend to have thicker fur than the monkeys at sea level. The genus name means “earless”; they have ears, of course, but the external ears are tiny and hard to see. Night monkeys have big brown eyes and therefore have increased ability to be active at night. They are called night monkeys because all species are active at night and are in fact the only truly nocturnal monkeys (an exception is the subspecies Aotus azarae azarae, which is cathemeral). Both male and female Night Monkeys weigh almost the same amount. For example, in one of these Night Monkeys, A. azarae, the male weighs 2.76 pounds while the female weighs 2.75 pounds.

Night monkeys make a notably wide variety of vocal sounds, with up to eight categories of distinct calls (gruff grunts, resonant grunts, screams, low trills, moans, gulps, sneeze grunts and hoots), and a frequency range of 190-1,950 Hz. Unusual among the New World monkeys, they are monochromats, that is, they have no colour vision, presumably because it is of no advantage given their nocturnal habits. They have a better spatial resolution at low light levels than other primates which contributes to their ability to capture insects and move at night.

All night monkeys form pair bonds, and live in family groups of the mated pair with their immature offspring. Family groups defend territories by vocal calls and scent marking. Only one infant is born each year. The male is the primary caregiver, and the mother only carries the infant for the first week or so of its life.

Night monkeys constitute one of the few monkey species that are affected by the often deadly human malaria protozoan Plasmodium falciparum, making them useful as non-human primate experimental models in malaria research.

 
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Monkeys : baboons

07 Apr

Baboons are African and Asian Old World monkeys belonging to the genus Papio, part of the subfamily Cercopithecinae. There are five species, which are some of the largest non-hominid members of the primate order; only the Mandrill and the Drill are larger. Previously, the closely related Gelada (genus Theropithecus) and two species of Mandrill and Drill (genus Mandrillus) were grouped in the same genus, and these Old World monkeys are still often referred to as baboons in everyday speech. They range in size and weight depending on species. The Guinea Baboon is 50 cm (20 inches) and weighs only 14 kg (30 lb) while the largest Chacma Baboon can be 120 cm (47 inches) and weigh 40 kg (90 lb). A group of baboons is collectively called a troop or congress, and more recently a flange.

all baboons have their looks :)

all baboons have their looks :)

Anatomy and physiology

All baboons have long dog-like muzzles; close-set eyes; heavy, powerful jaws; thick fur except on their muzzle; a short tail; and rough spots on their protruding buttocks, called ischial callosities. These calluses are nerveless, hairless pads of skin that provide for the sitting comfort of the baboon.

In all baboon species there is pronounced sexual dimorphism, usually in size but also sometimes in colour or canine development. Males of the Hamadryas Baboon species also have a large white mane.

baboons are ground dwelling monkeys -- inthu.co.uk

baboons

Baboons are terrestrial (ground dwelling) and are found in open savannah, open woodland and hills across Africa. Their diet is omnivorous, but mostly vegetarian; yet they eat insects and occasionally prey on fish, shellfish, hares, birds, vervet monkeys, and small antelopes. They are foragers and are active at irregular times throughout the day and night. They can raid human dwellings and in South Africa they have been known to prey on sheep and goats.

Their principal predators are man, the lion, both the spotted and striped hyenas and the leopard for babies, although they are tough prey for a leopard and large males will often confront them by flashing their eyelids, showing their teeth by yawning, making gestures, and chasing after the intruder/predator.

Baboons in captivity have been known to live up to 45 years, while in the wild their life expectancy is about 30 years.

Social systems

Most baboons live in hierarchical troops. Group sizes vary between 5 to 250 animals (often about 50 or so), depending on specific circumstances, especially species and time of year. The structure within the troop varies considerably between Hamadryas Baboons and the remaining species, sometimes collectively referred to as savanna’s baboons. The Hamadryas Baboon often appear in very large groups composed of many smaller harems (one male with four or so females), to which females from elsewhere in the troop are recruited while they’re still too young to breed. Other baboon species have a more promiscuous structure with a strict dominance hierarchy based on the matriline. The Hamadryas Baboon group will typically include a younger male, but he will not attempt to mate with the females unless the older male is removed.

Baboons can determine from vocal exchanges what the dominance relations are between individuals. When a confrontation occurs between different families or where a lower-ranking baboon takes the offensive, baboons show more interest in the exchange than exchanges between members of the same family or when a higher-ranking baboon takes the offensive. This is because confrontations between different families or rank challenges can have a wider impact on the whole troop than an internal conflict in a family or a baboon reinforcing its dominance.

The collective noun for baboons is commonly troop or congress, although flange is also increasingly used. This unusual term originates from a Not the Nine O’Clock News comedy sketch entitled “Gerald The Intelligent Gorilla” where it was used for comic effect.[

In the harems of the Hamadryas Baboons, the males jealously guard their females, to the point of grabbing and biting the females when

 
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Mysterious Bale monkey of Africa loves to eat bamboo

03 Apr

Ethiopia’s mysterious Bale monkey eats almost nothing but bamboo, according to the first study of the primate.

bale monkey

bale monkey

Discovered in 1902, little is known about the monkey, named after the region in Africa in which it lives.

But scientists have now discovered it spends most of its life in the trees of a bamboo forest, eating young leaves to avoid getting poisoned.

Very few primates depend on bamboo, and the Bale monkey’s reliance on it makes the primate vulnerable to extinction.

Researchers from Ethiopia, US and Norway describe the behaviour of the Bale monkey for the first time in the International Journal of Primatology.

They were always considered by scientists to be ‘too difficult to study’
Dr Peter Fashing
California State University, US

The Bale monkey (Chlorocebus djamdjamensis) is an arboreal and enigmatic primate restricted to the forests of the Bale Massif and Hagere Selam regions of southeastern Ethiopia.

Little information has been available on how this mysterious primate lives.

“They were always considered by scientists to be ‘too difficult to study’ due to the rough mountainous terrain and foggy conditions in the forests where they occur,” says Dr Peter Fashing from California State University, California, US, one of the co-authors of the study.

Between 2007 and 2008 the team studied two neighbouring groups of Bale monkeys in the Obobullu forest in southeastern Ethiopia, which lies to the east of the Bale mountains.

The researchers spent many months deep in the forest, following the primates and recording their behaviour and ecology.

“At the beginning, I had to habituate the very shy monkeys to my presence, but over time they came to trust me enough to let me watch them from a distance,” explains Mr Addisu Mekonnen from Addis Ababa University in Ethiopia, who led the study.

No taste for cyanide

The research team discovered several previously unknown Bale monkey populations.

The scientists also found that Bale monkeys are quite different to their closest relatives, other green or vervet monkeys belonging to the same genus.

“We found Bale monkeys to be highly specialised primates, relying entirely on the bamboo forest to meet their needs,” Mr Mekonnen says.

The monkeys feed on just 11 plant species.

However, of those bamboo leaves account for a remarkable 77% of their diet.

Most other forest monkeys eat far richer diets, typically consuming between 50 and 100 different plant species or more, says Dr Fashing.

Bale monkeys also consume mainly young bamboo leaves, perhaps to avoid being poisoned by cyanide that accumulates in mature leaves.

Food for thought

Only one type of primate is known to rely more heavily on bamboo than Bale monkeys – the bamboo lemurs of Madagascar, of which there are three species, each consuming a diet that is 90% bamboo.

“Bamboo is a key resource for the existence of Bale monkeys,” says Mr Mekonnen.

Yet bamboo in the Bale Massif is being commercially harvested.

“The loss of this resource would have [an equally profound] adverse effect on the long-term survival of this species.”

The revelations about the Bale monkey also highlight how little we still know about some primate species, says Dr Fashing.

“If we are to ensure the survival of these mysterious primates, we must first study their basic ecology and behaviour to determine what their conservation needs are,” he says.

“Prior to this study, we did not know just how dependent Bale monkeys are on bamboo for their survival.”

 
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