DRILL MONKEY

Description

The adult male drill is one of the more colorful monkeys in the world. A mature male has a red chin on a black face with raised grooves on the nose. The rump is colored pink, mauve and blue. These bright colors help his family follow him through the forest. Female drills are less colorful.

Habitat

The drill is mainly found in the African Rain Forests.

Behavior

A single male leads a group of around 20 females and is father to all the young. This group of 20 may join others forming super groups of over 200 individuals. They will often rub their chests onto trees to mark their territory.

A drill can live for about 28 years.

Diet

The drill is omnivorous, with a diet ranging from fruit, herbs, roots to small animals.

Lifestyle

Drills live in large social groups (as many as 20 individuals) with many dominant adult males (but only one leader).  These groups can merge with other groups, creating large groups of over 200 individuals. Besides facial expressions, drills also utilize a wide range of vocal, olfactory, visual and tactile forms of communication to keep their group together, as well as to keep other groups away. They mark their territory by rubbing their chests on trees. Drills are diurnal, so they are most active during the day.

Food

Drills are mainly frugivores (eating primarily fruit), but will also eat insects and edible plants. In addition to those items, the Zoo’s drills also eat vegetables, lettuce and a dry food containing vital nutrients.

Life Cycle

Females reach sexual maturity at about 3 years old, while males are sexually mature at about 6 years old. Gestation is 179-182 days, and a drill female usually gives birth to asingle offspring (there has been one documented case of twins). The offspring stays with its mother for 15-16 months until it is fully weaned. Males will usually disperse from their natal group to form new groups. The average life span is 28-30 years.

Some of My Neighbors (IN THE WILD)

Chimpanzees, olive pigeons, Rumpi mouse shrews, Preuss’s monkeys and African pygmy squirrels

Population Status & Threats

Drills are among Africa’s most endangered primates because their numbers have been declining in all known habitat areas for decades. The decline is due to illegal commercial hunting, habitat destruction and fragmentation, and human development. Unfortunately, fewer than 10,000 drills remain in the wild, and numbers may be as low as 4,000.  Drills are fully protected by law in Nigeria and Cameroon, and portions of their habitat are technically safeguarded as national parks.  However, little real protection from hunting exists for drills, even in so-called protected areas.

Three subspecies of common chimpanzees are distributed across the forest zone of Africa from Guinea to western Tanzania and Uganda. Another species of chimpanzees, the bonobo (Pan paniscus), is found exclusively in central Democratic Republic of Congo. In East Africa the chimpanzee is found in the wild in Tanzania and Uganda, but only in captivity in Kenya. Gombe National Park in Tanzania is the first park in Africa specifically created for chimpanzees.

Physical Characteristics
The chimpanzee has a thickset body with long arms, short legs and no tail. Much of the body is covered with long black hair, but the face, ears, fingers and toes are bare. They have hands that can grip firmly, allowing them to pick up objects. The discovery that they used “tools” for certain purposes surprised the world.

Likewise a chimp cannot swim in water because of the fat in their body.

Habitat
Chimps are mainly found in rain forests and wet savannas. While they spend equal time on land and in trees, they do most of their feeding and sleeping in trees.

Behavior
Chimps live in groups called troops, of some 30 to 80 individuals. These large groups are made up of smaller, very flexible groups of just a few animals, perhaps all females, all males or a mixed group.Chimps sometimes chew leaves to make them absorbent and then use them as a sponge, dipping them in water and sucking out the moisture. They also use grass stems or twigs as tools, poking them into termite or ant nests and eating the insects that cling onto them.

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They are able to wedge nuts between the roots of a tree and break the shells open with a stone.Chimps are both arboreal and terrestrial, spending much of their daytime hours on the ground. They are quadrupedal, walking quickly on all fours with the fingers half-flexed to support the weight of the forequarters on the knuckles. They occasionally walk erect for short distances.

Chimps are agile climbers, building nests high up in trees to rest in during midday and sleep in at night. They construct new nests in minutes by bending branches, intertwining them to form a platform and lining the edges with twigs. In some areas chimps make nests on the ground.

Diet

Chimps are diurnal (but often active on moonlit nights) and begin their activities at dawn. After descending from their night nests they hungrily feed on fruits, their principal diet, and on leaves, buds and blossoms. After a while their feeding becomes more selective, and they will choose only the ripest fruit. They usually pick fruit with their hands, but they eat berries and seeds directly off the stem with their lips. Their diet consists of up to 80 different plant foods.

Caring for the Young
The female chimp has an estrus cycle of about 34 to 35 days. While in heat, the bare skin on her bottom becomes pink and swollen, and she may mate with several males. She normally gives birth to just one baby, which clings tightly to her breast and, like a human baby, develops rather slowly. An infant can sit up at 5 months and stand with support at 6 months. It is still suckled and sleeps with its mother until about 3 years of age, finally becoming independent and separating from her at about 4 years. Sexual maturity is reached between 8 and 10 years.

Chimps are among the noisiest of all wild animals and use a complicated system of sounds to communicate with each other. A loud “wraaa” call, which can be heard more than a mile away, warns of something unusual or disturbing. They hoot “hoo-hoo-hoo,” scream, grunt and drum on hollow trees with the flat of their hands, sometimes for hours.

Chimps touch each other a great deal and may kiss when they meet. They also hold hands and groom each other. An adult chimp often has a special “friend” or companion with which it spends a lot of time. Female chimps give their young a great deal of attention and help each other with babysitting chores. Older chimps in the group are usually quite patient with energetic youngsters.

Predators
The number of chimps in the wild is steadily decreasing. The wilderness areas necessary to their survival are disappearing at an alarming rate as more forests are cut down for farming and other activities. As the human’s closest relative the chimp is vulnerable to many of the same diseases, and their capture for medical research contributes to their decline, especially in West Africa. as more forests are cut down for farm activities. In addition, recent outbreaks of the incurable disease Ebola hemorrhagic fever, threaten to decimate important chimpanzee populations in the Republic of Congo and Gabon.

Orangutan

Orangutans are the only exclusively Asian genus of extant great ape. The largest living  arboreal animals, they have longer arms than the other, more terrestrial, great apes.  They are among the most intelligent primates and use a variety of sophisticated tools,  also making sleeping nests each night from branches and foliage. Their hair is typically  reddish-brown, instead of the brown or black hair typical of other great apes.Native to Indonesia and Malaysia, orangutans are currently found only in rainforests  on the islands of Borneo and Sumatra, though fossils have been found in Java, the Thai-  Malay Peninsula, Vietnam and Mainland China. There are only two surviving species,  both of which are endangered: the Bornean Orangutan (Pongo pygmaeus) and the  critically endangered Sumatran Orangutan (Pongo abelii). The subfamily Ponginae also  includes the extinct genera Gigantopithecus and Sivapithecus. The word “orangutan”  comes from the Malay words “orang” (man) and “(h)utan” (forest); hence, “man of the forest”.

Orangutans live a more solitary lifestyle than the other great apes. Most social bonds occur between adult females and their dependent and weaned offspring. Adult males and independent adolescents of both sexes tend to live alone. The society of the orangutan is made up of resident and transient individuals of both sexes. Resident females live with their offspring in defined home ranges that overlap with those of other adult females, who may be their relatives like mothers and sisters. One to several resident female home ranges are encompassed within the home range of a resident male, who is their primary breeder.  Transient males and females range broadly.  They usually travel alone, but as sub-adults they may travel in small groups. However this behavior does not extend to adulthood. The social structure of the orangutan can be best described as solitary but social. As the ranges of males and females overlap, they commonly encounter each other while traveling and feeding and may have brief social interactions.Interactions between adult females range from friendly, to avoidance to antagonistic. Resident males may have overlapping ranges and interactions between them tend to be hostile.

During dispersal, females tend to settle in home ranges that overlap with their mothers. However, they do not interact when them any more than the other females and they do not seem to form bonds though affiliation, grooming, or agonistic support. Males disperse much farther from their mothers and enter into a transient phase. This phase lasts until a male can challenge and displace a dominant, resident male from his home range.There are dominance hierarchies between adult males that regularly encounter each other with the most dominant males being the largest and having the best body conditions. Adult males dominate sub-adult males. Both resident and transient orangutans aggregate on large fruiting trees to feed. The fruits tend to be abundant, so competition is low and individuals may benefit from social contacts. Orangutans will also form travelling groups in which members coordinate travel between food sources for a few days at a time. These groups tend to be made of only a few individuals. They also tend to be mating consortships, each made of an adult male and female traveling and mating.

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.

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 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

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.

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.”