Nella seconda parte di questa scheda scopriremo che il gorilla ci aiuterà a trovare la forza interiore, insegnerà a prenderci cura della nostra famiglia e dei nostri amici; nella prima invece vi propongo le schede informative di wikipedia di cui vi consiglio di visionare anche alla fonte originale per eventuali appronfondimenti.
Da Wikipedia, l'enciclopedia libera.
I gorilla (Gorilla gorilla I. Geoffroy, 1852) sono un genere di Primati della sottofamiglia degli ominini (Homininae) della famiglia delle scimmie antropomorfe (Hominidae). Sono l'unico genere attualmente vivente della tribù Gorillini.
Il genere comprende due specie e quattro sottospecie:
Gorilla gorilla - gorilla occidentale:
Gorilla gorilla gorilla - gorilla occidentale di pianura
Gorilla gorilla diehli - gorilla di Cross River
Gorilla beringei - gorilla orientale:
Gorilla beringei graueri - gorilla orientale di pianura
Gorilla beringei beringei - gorilla di montagna
È un animale grande e possente, dal caratteristico pelo nero e folto. Nonostante la mole e l'aspetto imponente, i gorilla sono animali relativamente pacifici e tranquilli. È raro vederli su due zampe: per lo più si trovano in posizione clinograda (inclinata in avanti), ed hanno una caratteristica andatura, camminano sulle nocche. I gorilla femmina e i giovani maschi si costruiscono un nido fra i rami più robusti degli alberi, ma spesso non a grandi altezze. I maschi adulti (detti Silverback per il color argento della schiena) invece trascorrono la maggior parte del tempo a terra, non temendo alcun pericolo, a guardia degli alberi dove vivono gli altri membri del branco. Questo atteggiamento è distintivo dei maschi adulti, ed è considerata all'interno del branco una manifestazione di potere.
Il gorilla è dotato di una notevole intelligenza. Un gorilla diventato famoso per la sua intelligenza è Koko, allevata dai ricercatori Penny Patterson, Carl Pribram, Saul Kitchener e Roger Fouts, che è in grado di esprimersi a gesti e di usare diversi oggetti umani.
Nel loro habitat i gorilla non hanno molti predatori. Talvolta i leopardi possono cacciare i cuccioli di gorilla, o anche le femmine, ma è raro che attacchino un maschio adulto.
FONTE IMMAGINE: http://it.wikipedia.org/wiki/File:Gorila.JPG
L'altezza media dei maschi adulti si aggira intorno ai 160-170 cm, e il peso intorno ai 140-180 kg. Le femmine adulte sono spesso di metà stazza rispetto a un "silverback": la loro altezza si aggira intorno ai 140 cm, e il peso tra i 70 ed i 100 kg. Eccezionalmente, è stato individuato un silverback di oltre 183 cm e 204.5 kg di peso. Talvolta in cattività i maschi adulti possono raggiungere una massa eccessiva, come nel caso di un gorilla obeso che ha registrato un peso pari a 270 kg.
I gorilla sono animali sociali, che vivono in branchi composti in media da una decina di esemplari. A capo del gruppo vi è di solito un possente maschio "silverback" cioè dalla schiena d'argento, che guida il branco nei suoi spostamenti attraverso la foresta e difende gli altri membri del gruppo da eventuali attacchi.
La locomozione è in genere quadrupede e avviene poggiando a terra le nocche degli arti anteriori.
La longevità è compresa tra 30 e 40 anni in natura e può arrivare a 50 anni in cattività.
Il gorilla nella cultura e nell'immaginario popolare
Sui gorilla si sono diffuse molte leggende, quasi tutte false, spesso inventate dai primi uomini - colonizzatori europei - che li scoprirono. Li si dipingeva ad esempio come animali feroci e violenti, e si riteneva inoltre che non si potessero portare le donne nelle spedizioni africane perché i gorilla le avrebbero violentate. Oggi tali credenze sono state superate.
Una delle principali studiose di gorilla del XX secolo è stata Dian Fossey, uccisa probabilmente dai bracconieri. La sua vita ha ispirato un film, Gorilla nella nebbia.
Il gorilla è un animale molto famoso ed è spesso simboleggiato nella cultura popolare. Basti pensare ad esempio al personaggio dei cartoni animati Magilla Gorilla o al leggendario King Kong. Al gorilla si ispira anche il personaggio di Donkey Kong, noto videogioco della Nintendo.
Il termine "gorilla" oggi viene spesso usato per indicare le guardie del corpo, a sottolineare la loro possanza fisica.FONTE:
Gorilla gorilla diehli
Da Wikipedia, l'enciclopedia libera.
Il gorilla del Cross River (Gorilla gorilla diehli (Matschie, 1904)) è una sottospecie di gorilla occidentale (Gorilla gorilla) sull'orlo dell'estinzione. Prende il nome dal fiume Cross River, un importante corso fluviale della Nigeria sudorientale.
Studi recenti sul comportamento
Nel 2005 gli scienziati della Wildlife Conservation Society, mentre stavano osservando dei gorilla di questa sottospecie, hanno documentato un caso di utilizzo di utensili da parte di questi animali. I ricercatori hanno infatti scoperto che i gorilla utilizzano dei rametti per saggiare la profondità dei torrenti prima di attraversarli.
Uno studio pubblicato nel 2007 sul Journal of Primatology ha annunciato la scoperta di varie reazioni aggressive a possibile minacce dell'uomo. Gli scienziati coinvolti nello studio hanno «riscontrato alcuni casi di gorilla che lanciavano bastoni e ciuffi d'erba». Questo fatto è insolito, poiché quando i gorilla entrano in contatto con l'uomo solitamente fuggono e solo raramente effettuano delle cariche.
FONTE IMMAGINE: http://commons.wikimedia.org/wiki/File:Cross-river-gorilla.jpg
FONTE IMMAGINE: http://it.wikipedia.org/wiki/File:I%27m_sooooo_tired.jpgFONTE:
From Wikipedia, the free encyclopedia
Gorillas are the largest extant species of primates. They are ground-dwelling, predominantly herbivorous apes that inhabit the forests of central Africa. Gorillas are divided into two species and either four or five subspecies. The DNA of gorillas is highly similar to that of a human, from 95–99% depending on what is counted, and they are the next closest living relatives to humans after the bonobo and chimpanzee.
Gorillas' natural habitats cover tropical or subtropical forests in Africa. Although their range covers a small percentage of Africa, gorillas cover a wide range of elevations. The mountain gorilla inhabits the Albertine Rift montane cloud forests of the Virunga Volcanoes, ranging in altitude from 2,200–4,300 metres (7,200–14,100 ft). Lowland gorillas live in dense forests and lowland swamps and marshes as low as sea level, with western lowland gorillas living in Central West African countries and eastern lowland gorillas living in the Democratic Republic of the Congo near its border with Rwanda.
The American physician and missionary Thomas Staughton Savage and naturalist Jeffries Wyman first described the western gorilla (they called it Troglodytes gorilla) in 1847 from specimens obtained in Liberia. The name was derived from Greek Γόριλλαι (Gorillai), meaning "tribe of hairy women", described by Hanno the Navigator, a Carthaginian navigator and possible visitor (circa 480 BC) to the area that later became Sierra Leone.
Evolution and classification
The closest relatives of gorillas are chimpanzees and humans, all of the Hominidae having diverged from a common ancestor about 7 million years ago. Human genes differ only 1.6% on average from their corresponding gorilla genes in their sequence, but there is further difference in how many copies each gene has. Richard Dawkins in his book The Ancestor’s Tale (Boston: Houghton Mifflin, 2004) proposes that gorillas are descended from Australopithecus Robustus (parnthropus) type species. For instance Paranthropus aethiopicus has characteristic gorilla-like crests on its skull. In other words the ancestors of gorillas are Paranthropus. Until recently there was considered to be a single gorilla species, with three subspecies: the western lowland gorilla, the eastern lowland gorilla and the mountain gorilla. There is now agreement that there are two species with two subspecies each. More recently it has been claimed that a third subspecies exists in one of the species. The separate species and subspecies developed from a single type of gorilla during the Ice Age, when their forest habitats shrank and became isolated from each other.
Primatologists continue to explore the relationships between various gorilla populations. The species and subspecies listed here are the ones upon which most scientists agree.
Western gorilla (Gorilla gorilla)
Western lowland gorilla (Gorilla gorilla gorilla)
Cross River gorilla (Gorilla gorilla diehli)
Eastern gorilla (Gorilla beringei)
Mountain gorilla (Gorilla beringei beringei)
Eastern lowland gorilla (Gorilla beringei graueri)
The proposed third subspecies of Gorilla beringei, which has not yet received a trinomen, is the Bwindi population of the mountain gorilla, sometimes called the Bwindi gorilla.
Some variations that distinguish the classifications of gorilla include varying density, size, hair color, length, culture, and facial widths. There are now thought to be over 100,000 western lowland gorillas in the wild, with 4,000 in zoos; eastern lowland gorillas have a population of 4,000 in the wild and 24 in zoos. Mountain gorillas are the most severely endangered, with an estimated population of about 620 left in the wild and none in zoos.
Gorillas move around by knuckle-walking, although they sometimes walk bipedally for short distances while carrying food or in defensive situations. Adult males, also called silverbacks, range in height 1.65–1.75 metres (5 ft 5 in–5 ft 9 in), and in weight 140–200 kg (310–440 lb). Adult females are often half the size of a silverback, averaging about 1.4 metres (4 ft 7 in) tall and 100 kg (220 lb). Occasionally, a silverback of over 1.8 metres (5 ft 11 in) and 230 kg (510 lb) has been recorded in the wild. Obese gorillas in captivity have reached a weight of 270 kg (600 lb). Gorillas have a facial structure which is described as mandibular prognathism, that is, their mandible protrudes farther out than the maxilla. Adult males also have a prominent sagittal crest.
The eastern gorilla is more darkly colored than the western gorilla, with the mountain gorilla being the darkest of all. The mountain gorilla also has the thickest hair. The western lowland gorilla can be brown or grayish with a reddish forehead. In addition, gorillas that live in lowland forests are more slender and agile than the more bulky mountain gorilla. The eastern gorilla also has a longer face and broader chest than the western gorilla.
Studies have shown that gorilla blood is non-reactive to anti-A and anti-B monoclonal antibodies which would, in humans, indicate type O blood. However, due to novel sequences it is different enough to not conform with the human ABO blood group system, which the other great apes fit into. Like humans, gorillas have individual finger prints. Their eye color is dark brown, framed by a black ring around the iris. Similar to humans, the leading cause of death in gorillas is cardiovascular disease.
Behavior and ecology
Range and habitat
Gorillas have a patchy distribution. The range of the two species is separated by the Congo river and its tributaries. The western gorilla lives in west central Africa while the eastern gorilla lives in east central Africa. Between the species and even within the species, gorillas live in a variety of habitats and elevations. Gorilla habitat ranges from montane forests to swamps. Eastern gorilla live in montane and submontane forests ranging 650–4000 m (2132-13,123 ft). Mountain gorillas live in the montane forests at the higher ends of the elevation range while eastern lowland gorillas live in submotane forests at the lower ends of the elevation range. In addition, eastern lowland gorillas live in montane bamboo forests as well as lowland forests ranging from 600–3308 m (1969-10,853 ft) in elevation. Western gorillas live in both lowland swamp forests and montane forests and live in elevations ranging from sea level to 1600 m (5249 ft). Western lowland gorillas live in swamp and lowland forests ranging up to 1600 m (5249 ft) and Cross River gorillas live in low-lying and submontane forests ranging 150–1600 m (492–5249 ft).
Food and foraging
A gorilla's day is synchronized, divided between rest periods and travel or feeding periods. There are dietary differences between and within species. Mountain gorillas mostly eat foliage such as leaves, stems, pith, and shoots while fruit makes up a very small part of their diet. They primarily eat bamboo. The food that mountian gorillas eat is widely distributed and both individuals and groups do not have to compete with each other. Their home ranges average 3–15 km2 (1.16–5.79 mi2), and their movements range around 500 m (0.311 mi) or less on an average day. Despite eating a few species in each habitat, mountain gorillas have a flexible diet and can live in a variety of habitats.
Easten lowland gorillas have a more diverse diet which varies seasonally. Leaves and pith are commonly eaten but fruits can make up as much as 25% of their diet. Since fruit is less available, lowland gorillas must travel farther each day and have home ranges that vary from 2.7–6.5 km2 (1.04 to 2.51 mi2) with day ranges 154–2280 m (0.096–1.42 mi). Eastern lowland gorillas will also eat insects, preferably ants. Western lowland gorillas depend on fruits more than the others and they are more dispersed across their range. They travel even further than the other gorilla subspecies, at 1105 m (0.687 mi) per day on average, and have larger home ranges of 7–14 km2 (2.70–5.41 mi2). Western lowland gorillas have less access to terrestrial herbs, although they can access aquatic herbs in some areas. Termites and ants also are also eaten.
Gorillas rarely drink water "because they consume succulent vegetation that is comprised of almost half water as well as morning dew", although both mountain and lowland gorillas have been observed drinking.
One possible predator of gorillas is the leopard. Gorilla remains have been found in leopard scat but it is possible that this may be the result of scavenging. When the group is attacked by humans, leopards, or other gorillas, an individual silverback will protect the group, even at the cost of his own life. George Schaller reported that a silverback gorilla and a leopard were both found dead from mutually inflicted wounds.
Gorillas live in groups called troops. Troops tend to be made of one adult male or silverback, multiple adult females and their offspring. However, multi-male troops also exist. Silverbacks are typically more than 12 years of age and named for the distinctive patch of silver hair on their back which comes with maturity. They also have large canine teeth which also come with maturity. Both males and females tend to emigrate from their natal groups. For mountain gorillas, females disperse from their natal troops more than males. Mountain gorillas and western lowland gorillas also commonly transfer to second new groups. Mature males tend to also leave their groups and establish their own troops by attracting emigrating females. However, male mountain gorillas sometimes stay in their natal troops and become subordinate to the silverback. If the silverback dies, these males may be able to become dominant or mate with the females. This behavior has not been observed in eastern lowland gorillas. In a single male group, when the silverback dies, the females and their offspring disperse and find a new troop. Without a silverback to protect them, the infants will likely fall victim to infanticide. Joining a new group is likely to be a tactic against this. However while gorilla troops usually disband after the silverback dies, female eastern lowlands gorillas and their offspring have been recorded staying together until a new silverback transfers into the group. This likely serves as protection from leopards. All male troops have also been recorded.
The silverback is the center of the troop's attention, making all the decisions, mediating conflicts, determining the movements of the group, leading the others to feeding sites and taking responsibility for the safety and well-being of the troop. Younger males subordinate to the silverback, known as blackbacks, may serve as backup protection. Blackbacks are aged between 8 and 12 years of age and lack the silver back hair. The bond a silverback has with his females forms the core of gorilla social life. Bonds between them are maintained by grooming and stay close together. Females form strong relationships with males to gain mating opportunities and protection from predators and infanticidal outside males. However aggressive behaviors between males and females do occur but rarely lead to serious injury. Relationships between females may vary. Maternally related females in a troop tend to be friendly towards each other and associate closely. Otherwise, females have few friendly encounters and commonly act aggressively towards each other. Females may fight for social access to males and a male may intervene. Male gorillas have weak social bonds, particularly in multi-male groups with apparent dominance hierarchies and strong competition for mates. However, males in all-male groups tend to have friendly interactions and socialize through play, grooming and staying together, and occasionally they even engage in homosexual interactions.
FONTE IMMAGINE: http://commons.wikimedia.org/wiki/File:Nshongi_Gorilla_Group-2,_by_Justin_Norton.jpg
Twenty-five distinct vocalizations are recognized, many of which are used primarily for group communication within dense vegetation. Sounds classified as grunts and barks are heard most frequently while traveling, and indicate the whereabouts of individual group members. They may also be used during social interactions when discipline is required. Screams and roars signal alarm or warning, and are produced most often by silverbacks. Deep, rumbling belches suggest contentment and are heard frequently during feeding and resting periods. They are the most common form of intragroup communication. Severe aggression is rare in stable groups, but when two mountain gorilla groups meet, the two silverbacks can sometimes engage in a fight to the death, using their canines to cause deep, gaping injuries. The entire sequence has nine steps: (1) progressively quickening hooting, (2) symbolic feeding, (3) rising bipedally, (4) throwing vegetation, (5) chest-beating with cupped hands, (6) one leg kick, (7) sideways running, two-legged to four-legged, (
slapping and tearing vegetation, and (9) thumping the ground with palms to end display.
Gorillas are considered[by whom?] highly intelligent. A few individuals in captivity, such as Koko, have been taught a subset of sign language. Like the other great apes, gorillas can laugh, grieve, have "rich emotional lives," develop strong family bonds, can make and use tools, and can think about the past and future. Some researchers believe that gorillas have spiritual feelings or religious sentiments. Gorillas have been shown to have cultures in different areas revolving around different methods of food preparation, and gorillas will show individual color preferences.
The following observations were made by a team led by Thomas Breuer of the Wildlife Conservation Society in September 2005. Gorillas are now known to use tools in the wild. A female gorilla in the Nouabalé-Ndoki National Park in the Republic of Congo was recorded using a stick as if to gauge the depth of water whilst crossing a swamp. A second female was seen using a tree stump as a bridge and also as a support whilst fishing in the swamp. This means that all of the great apes are now known to use tools.
In September 2005, a two and a half year old gorilla in the Republic of Congo was discovered using rocks to smash open palm nuts inside a game sanctuary. While this was the first such observation for a gorilla, over 40 years previously chimpanzees had been seen using tools in the wild 'fishing' for termites. Great apes are endowed with a semi-precision grip, and have been able to use both simple tools and even weapons, by improvising a club from a convenient fallen branch.
Interactions with humans
The word "gorilla" comes from the history of Hanno the Navigator, a Carthaginian explorer on an expedition on the west African coast. They encountered "a savage people, the greater part of whom were women, whose bodies were hairy, and who our interpreters called Gorillae". The word was then later used as the species name, though it is unknown whether what these ancient Carthaginians encountered were truly gorillas, another species of ape or monkeys, or humans.
American physician and missionary Thomas Staughton Savage obtained the first specimens (the skull and other bones) during his time in Liberia in Africa. The first scientific description of gorillas dates back to an article by Savage and the naturalist Jeffries Wyman in 1847 in Proceedings of the Boston Society of Natural History, where Troglodytes gorilla is described, now known as the Western Gorilla. Other species of gorilla are described in the next couple of years.
Explorer Paul du Chaillu was the first westerner to see a live gorilla during his travel through western equatorial Africa from 1856 to 1859. He brought dead specimens to the UK in 1861.
The first systematic study was not conducted until the 1920s, when Carl Akeley of the American Museum of Natural History traveled to Africa to hunt for an animal to be shot and stuffed. On his first trip he was accompanied by his friends Mary Bradley, a mystery writer, and her husband. After their trip, Mary Bradley wrote On the Gorilla Trail. She later became an advocate for the conservation of gorillas and wrote several more books (mainly for children). In the late 1920s and early 1930s, Robert Yerkes and his wife Ava helped further the study of gorillas when they sent Harold Bigham to Africa. Yerkes also wrote a book in 1929 about the great apes.
After World War II, George Schaller was one of the first researchers to go into the field and study primates. In 1959, he conducted a systematic study of the mountain gorilla in the wild and published his work. Years later, at the behest of Louis Leakey and the National Geographic, Dian Fossey conducted a much longer and more comprehensive study of the mountain gorilla. It was not until she published her work that many misconceptions and myths about gorillas were finally disproved, including the myth that gorillas are violent.
The eastern gorilla is listed as endangered on the IUCN Red List, with the mountain gorilla listed as Critically Endangered. The western gorilla and its subspecies are also listed as Critically Endangered. Threats to gorilla survival include habitat destruction and poaching for the bushmeat trade. In 2004, a population of several hundred gorillas in the Odzala National Park, Republic of Congo was essentially wiped out by the Ebola virus. A 2006 study published in Science concluded that more than 5,000 gorillas may have died in recent outbreaks of the Ebola virus in central Africa. The researchers indicated that in conjunction with commercial hunting of these apes, the virus creates "a recipe for rapid ecological extinction." Conservation efforts include the Great Ape Survival Project, a partnership between the United Nations Environment Programme and the UNESCO, and also an international treaty, the Agreement on the Conservation of Gorillas and Their Habitats, concluded under UNEP-administered Convention on Migratory Species. The Gorilla Agreement is the first legally binding instrument exclusively targeting Gorilla conservation and came into effect on 1 June 2008.
Since they came to the attention of western society in the 1860s, gorillas have been a recurring element of many aspects of popular culture and media. For example, gorillas have featured prominently in monstrous fantasy films such as King Kong, and pulp fiction such as the stories of Tarzan and Conan the Barbarian have featured gorillas as physical opponents to the titular protagonists.FONTE:
Cross River gorilla
From Wikipedia, the free encyclopedia
The Cross River gorilla (Gorilla gorilla diehli) is a subspecies of the western gorilla (Gorilla gorilla) that can be found on the border between Nigeria and Cameroon, in both tropical and subtropical moist broadleaf forests which are also home to the Nigeria-Cameroon Chimpanzee, another subspecies of great ape. While all western gorillas are Critically Endangered (in the case of the western lowland gorilla due in part to Ebola virus), the Cross River gorilla is the most endangered of the African apes, and is one of the world's 25 most endangered primates according to the IUCN Primate Specialist Group.
The Cross River gorilla differs from the western lowland gorilla in both skull and tooth dimensions. Based on these differences, the Cross River gorilla was described as a distinct subspecies in 2000, though previous analyses had also recognized the distinctiveness of these gorillas.
Estimates on the number of Cross River gorillas remaining is about 280 in the wild, concentrated in approximately 11 locations. Recent genetic research and field surveys suggest that these locations are linked by the occasional migration of individual gorillas. The nearest population of western lowland gorilla is some 250 km away. Both loss of habitat and intense hunting for bushmeat have contributed to the decline of this subspecies. A conservation plan for the Cross River gorilla was published in 2007 and outlines the most important actions necessary to preserve this subspecies. In 2008, the government of Cameroon created the Takamanda National Park on the border with Nigeria, as an attempt to protect these gorillas. The park now forms part of an important trans-boundary protected area with Nigeria’s Cross River National Park, safeguarding an estimated 115 gorillas—a third of the Cross River gorilla population—along with other rare species. The hope is that the gorillas should be able to move between the Takamanda reserve in Cameroon over the border to Nigeria's Cross River National Park.
In 2009, the camera-shy Cross River gorilla was finally captured on professional video on a forested mountain in Cameroon.
A study published in 2007 in the American Journal of Primatology announced the discovery of the fighting back against possible threats from humans. They "found several instances of gorillas throwing sticks and clumps of grass". This is unusual, because gorillas usually flee and rarely charge when encountered by humans.
FONTE IMMAGINE: http://en.wikipedia.org/wiki/File:Susa_group,_mountain_gorilla.jpg