Where Are the Gorillas?

It was not long after the discovery of the gorilla, and its description (under the name Troglodytes gorilla), that zoologists began to think that there might be more than one single species. In those early days, many species were described with very poor material. Sometimes no place of origin was given at all or the person who published the description had no idea of the geography of Africa, and confused or misspelled places in his publication. Nowadays such descriptions would not be acceptable, but standards were different until the beginning of the 20th century, and even beyond. It is not easy, in many cases, to find out where a particular gorilla type specimen was collected.
A type specimen is an individual that serves as model for the description of a new species or subspecies - usually the skull or skin is the main basis for description in mammals. Gorilla taxonomy is today based mainly on skull measurements; in the past few years, DNA sequences had begun being used too, although this method is not as easy and reliable as experts had hoped and is still being improved.
At the turn of the 19th to the 20th century, taxonomy was still interpreted very individually. Paul Matschie, of Berlin, was convinced that each river valley had its own gorilla species - he is the person who described more species/subspecies than anybody else (Groves 2001). Many type specimens are still in the Museum für Naturkunde, where he worked. Cameroon was a German colony at that time and many Germans who collected gorillas there gave them to Matschie for study; understandably, therefore, most gorilla type specimens are from Cameroon.
This article was inspired by Hendrik Turni's studies of the gorilla type specimens in the Berlin Natural History Museum. The descriptions of the specimens he studied as well as all other gorilla type specimens are discussed with a focus on the places where they were found, and the present situation at each place is explained, in as far as it is known. The headings give the names of the currently accepted taxa.

Gorilla gorilla gorilla - Western Lowland Gorilla
Troglodytes gorilla Savage, 1847. Thomas Savage described the first gorilla on the basis of a specimen (skull and skeleton) that is now in the Museum of Comparative Zoology in Harvard.
It was collected in "Mpongwe, Gaboon estuary" or "Empongwe, near the river Gaboon". Mpongwe is not a town, but the name of a people living close to the southern bank of the Gabon river (about 0° 4' N, 9° 39' E).
When Tutin & Fernandez (1984) censused the gorillas of Gabon more than 20 years ago, they did not find any gorilla signs in the regions north and south of the Gabon river. The southern bank of the river is now the Pongara National Park, famous for its mangroves and beaches, but with no gorillas. In the Wonga-Wongué Presidential Reserve further south, Tutin & Fernandez (1984) found no gorillas either, but Blom et al. (1992) later confirmed the presence of gorillas there.
Synonyms of this species are Troglodytes savagei Owen, 1848 and Satyrus adrotes Mayer, 1856. The authors of these names were not describing new species, but merely renaming Troglodytes gorilla. In the mid-19th century, before the institution of formal rules of nomenclature, it was all too common for authors to substitute names which they preferred for names which others had previously bestowed.
Gorilla Gina Geoffroy Saint-Hilaire, 1853, is probably also just an objective synonym of Troglodytes gorilla. Geoffroy Saint-Hilaire stated that this species is found at the "West coast of Africa - Gabon", a very vague locality, but as he explained that the gorillas he analyzed came exactly from the same region as the type specimen of Savage, and he never explicitly stated that he regarded them as a new species, the name should probably be regarded as another replacement name. He was convinced that the gorilla should not be included in the same genus as the chimpanzee (Troglodytes at that time), and described a new genus Gorilla. As tautonymy was not usual in those days, Geoffroy Saint-Hilaire felt himself justified in giving a new specific name. At first he used Owen's name savagei, but later he substituted his own name, referring obscurely to motives "que l'on comprendra facilement". "Gina" was, he noted, the name of the gorilla in Gabon - spelt Gina, Engina, N'gina, En-Gina, D'jina, Engé-ena, Ngena or Ingé-ena.
Gorilla castaneiceps Slack, 1862. In this case, the species description comprises only the following sentence: "Dr. Slack called the attention of the members to a coloured cast of the head of a gorilla, which he characterized as a new species under the name of Gorilla castaneiceps." He did not mention where this gorilla had been found.
No skull exists, only the cast mentioned in the description; it is at the Academy of Natural Sciences in Philadelphia. Slack classified this specimen as a new species because of its reddish hair on the head. During the following decades, however, it became clear that the colour is not a good criterion for taxonomy (Rothschild 1905). When C. P. Groves saw the cast in 1965, it had been painted entirely black!
Gorilla mayêma Alix and Bouvier, 1877. This specimen included the skeleton and skin of a young female that was originally at the Muséum d'Histoire Naturelle in Paris, but it had disappeared already in 1920; in 1964, C. P. Groves found a very small female gorilla skull, no. 9772 in the old collection of the Laboratoire d'Anatomie Comparée, which according to a catalogue entry by Rode may be the type skull. The reputed type skull, if that is indeed what it is, is the smallest fully mature gorilla skull ever studied by C. P. Groves, only 206 mm in total length. The next smallest skull, in the Naturhistorisches Museum in Vienna (from the Ogooué River), measures 215 mm.
The description of the skull led Rothschild (1905) to identify this form as a chimpanzee, not a gorilla ("the Gorilla manyema of Alix and Bouvier I believe to be a very large ape of the group of Simia vellerosus Gray, and not a Gorilla at all").
Elliot (1912) created a new genus and called the species Pseudogorilla mayema, because some additional specimens in Frankfurt seemed much smaller than the other gorillas that were known at that time (see below). We will return to a discussion of these particular specimens below.
According to the description, the type specimen was collected in "Congo, Landana, sur les rives du Quilo, 4°35' S, près du village du roi Mayêma". This locality is confusing, as Landana is (and also was at that time) not in Congo and not near the Kouillou (Quilo) River, but in Cabinda. Later, Famelart (1883) stated that the specimen was bought at Conde near Landana, and Matschie (1904) wrote that it was from the Mayombe area.
Several places called Conde exist now in Cabinda (Microsoft Expedia map), and it is not clear at which one the type specimen was found. But probably the gorilla came from the Mayombe Forest (which is not too far from any of the places called Conde). A few years ago, during the first survey for many years, Tamar Ron saw gorillas in Cabinda's Maiombe Forest. This confirmed that gorillas are still living there, although their number and distribution remain uncertain and their situation is critical.

Gorilla gigas Haeckel, 1903. The type specimen is now in the British Museum (Natural History). According to Haeckel, the gorilla was shot by H. Paschen at "Yaunde, im Hinterlande von Kamerun" - Yaounde, in the hinterland of Cameroon. Although Haeckel published a photograph of the dead gorilla in an African village, there is no evidence that this settlement was Yaounde itself, which may have been only the place from which it was shipped to Europe. Nowadays, there is no forest left around the town of Yaounde (Eerens et al.).
Gorilla gorilla matschiei Rothschild, 1905 is an objective synonym of Gorilla gigas. Haeckel (1903) stated that Paschen's gorilla had been purchased for the Tring Museum (owned by Lord Rothschild) for 20,000 Marks. When Rothschild (1905) described Gorilla gorilla matschiei, he did not specify a type; but a skeleton in the Tring Museum (formerly numbered A.D.15, now no. 1939.3406 of the Natural History Museum, London, with associated mounted skin no. 1939.3405), labelled as type, is the Paschen specimen from Yaounde - in other words the same specimen that had been used by Haeckel as type of his Gorilla gigas. Rothschild created a new subspecies including all the gorillas from southern Cameroon (at that time only Gorilla gigas had been described) to discern them from the Gabonese gorillas - who represent the typical Gorilla gorilla.
Gorilla jacobi Matschie, 1905. The type specimen is in the Berlin Natural History Museum (Matschie's no. 28051; now no. 83558). The skull is the largest gorilla skull in any museum seen by C. P. Groves, with total length of 340 mm (the next largest scale is that of a mountain gorilla in the Tervuren Museum measuring 338 mm).
This skull had been collected by lieutenant Jacob "auf der Station Lobo-Mündung, die nicht weit von den Zuflüssen des Njong gelegen ist, aber schon im Flußgebiet des Dscha" - at the Lobo Mouth station, watershed of the rivers Dja and Nyong, but closer to the Dja region. The Lobo Mouth station was not found on old maps.
No gorilla survey has been made recently in the area where this specimen was collected, but the Dja Reserve, which is very close by, is an important protected area for gorilla conservation (Williamson & Usongo 1996).
Gorilla gorilla schwarzi Fritze, 1912. The type specimen, a large male, originally in the Karlsruhe Natural History Museum, Germany, was destroyed during the second world war.
In the description, the type locality is "Sogemafarm am Djahfluss, Südkamerun" (Sogemafarm at the Dja River, southern Cameroon). The place called "Sogemafarm" is correctly spelt "Sugemafam" (approx. 2° 25' N, 12° 50' E; Andrees Handatlas 1912).
During a survey in 2002, a high gorilla density was found in the Mengamé Reserve. The density was especially high in the swampy regions in the southeastern part of the reserve, which is close to the type locality (Ellis 2003). Gorillas are threatened in this area by hunting and forest destruction. The distance to villages and therefore to human activity appears to determine the distribution of the gorillas: They are absent from areas where there is regular human activity and noise.
Across the border in Gabon's Minkebe area, Walsh et al. (2003) reported a catastrophic decline in gorilla density around the year 2000. The reason was bushmeat hunting and, even more important in this case, Ebola. According to Huijbregts et al. (2003) the number of gorillas decreased by 90% prior to and after the 1994 and 1996 Ebola epidemics in the Minkebe Forest. It is unknown whether Ebola also affected the gorillas across the border in Cameroon.
Gorilla hansmeyeri Matschie, 1914. The type specimen, an adult male, was mounted in the Berlin Natural History Museum, and the skeleton is no. 17960 (now missing). The skull, 333 mm long, is not as large as that of G. jacobi, but is nonetheless one of the largest gorilla skulls in any museum.
The type locality is "Straße von Assobam zwischen Mensima und Bimba südlich des Dumeflusses westlich von Mokbe" in Cameroon (Assobam Road, between Mensima and Bimba, south of the Dume River, west of Mokbe). Mensima is correctly spelt the Mesima region. The type locality is about 4° 4' N, 14° E (Andrees Handatlas 1912).
No gorilla survey has been made so far in the area where this gorilla was collected. The nearest area outside of the Dja Reserve where the presence of gorillas was confirmed recently is the Ntonga Research Site, south of Abong Mbang. At this site, Dupain et al. (2004) found high densities of both gorillas and chimpanzees; these densities are amongst the highest reported so far in Cameroon. Recently, this gorilla population was reduced by an Anthrax outbreak.
Gorilla zenkeri Matschie, 1914. The type specimen, a young male, is in the Berlin Natural History Museum (no. 30260/30261). The type skull, no. 30261 in the museum, is only 299 mm long, a small specimen even though it is not completely mature.
It was collected at "Mbiawe am Lokundje, 6 Stunden flußabwärts von Bipindi am weißen Berge" (Mbiawe on the Lokundje River, 6 hours downstream from Bipindi at the white mountain), at about 3° 11' N, 10° 21' E.
The type locality is situated between the Campo-Ma'an Reserve and the Douala-Edéa Wildlife Reserve of today. Gorillas are present in Campo-Ma'an but are absent from Douala-Edéa.
Gorilla gorilla halli Rothschild, 1927. The type specimen is a mounted skin, no. 1939.3415 (formerly G 15), in the British Museum (Natural History); the skeleton which according to Jenkins (1990) almost certainly represents the same individual is no. 1986.757; when C. P. Groves was studying gorillas in the 1960s it had not yet been identified, so we have no measurements for it, nor did Rothschild give any length measurements.
It was collected in "Punta Mbouda, Spanish Guinea", which is in fact Punta Mbonda in the north of Río Muni, Equatorial Guinea (2° 6' N, 9° 46' E).
The most recent gorilla census in Equatorial Guinea was conducted in 1990 by Gonzalez-Kirchner (1997). He found gorillas along the river Ntem (Campo), not far from Punta Mbonda; the gorilla density there was higher than anywhere else in Equatorial Guinea. According to his study, gorillas were hunted for food everywhere in Río Muni, and their number and distribution area was reduced considerably during the second half of the 20th century (and probably this is still continuing). The Río Campo Faunal Reserve includes a part of the gorilla distribution area confirmed by Gonzalez-Kirchner, however, and it is hoped that gorillas still live there. Matthews & Matthews (2004) found that the gorilla density across the border in the Campo Forest, Cameroon (which includes a logging concession and the southern part of the Campo Ma'an National Park) is very low.
Gorilla uellensis Schouteden, 1927. This species was described from three or four specimens in the Tervuren Museum, Belgium. They are labelled "Près de Djabbir (= Bondo)" and "Mobele, Itimbiri". The latter locality is also cited by Schouteden (1930) as "Mobili, Itimbiri (Mbili)". Neither "Mobele" nor "Mobili" or "Mbili" could be found in old maps. It is possible that it means in fact the town of Bili - although this is far from the river Itimbiri.
There are in fact four specimens in the Tervuren museum which are labeled as syntypes of G. uellensis. No. 100 is the blackened cranium of an adult male, evidently kept for some time in a smoky African hut; no. 101 is a subadult male cranium, similarly treated. These two are both labelled "Djabbir (Bondo)". No. 102 is an adult female cranium, this time with a mandible, not smoke blackened. No. 103 is a mandible of an adult male, not smoke blackened; curiously it fits exactly with number 100. 102 and 103 are both labelled "Mbili, Itimbiri". The possibility remains, therefore, that three specimens were involved rather than four; another possibility is that there were indeed four, and that they were from two localities, the two from Bondo being trophy skulls, kept in the hunters' huts for some time, and the other two were shot at the localities stated. The skulls are ordinary western gorillas, with nothing particularly to distinguish them; the adult male skull is 311 mm long, the adult female 217 mm.
While Coolidge (1929) first doubted that the gorilla was really from that area, he later accepted the type locality given by the collector (1936). It remains a mystery whether gorillas still lived there in the 20th century. During a recent survey by George B. Schaller and others in the Bili district, no traces of gorillas were found. Makassi, a citizen of Bili, surveyed forested areas in the Bondo district in 2002, but likewise found no trace of gorillas; he told Colin P. Groves in 2003 that his survey was incomplete and that he intended to return at a later date.
Gorilla (Pseudogorilla) ellioti Frechkop, 1943 (Pseudogorilla mayema Elliot). The type specimens are in the Senckenberg Museum, Frankfurt.
Under the impression that the skulls in Frankfurt were intermediate between gorillas and chimpanzees, Elliot hypothesised that they represented Alix & Bouvier's Gorilla mayéma, and erected a new genus, Pseudogorilla, but he admitted that there was no real guarantee that his Pseudogorilla mayéma was in actuality the same species as Alix and Bouvier's; anyone thinking they were different would, he noted, be at liberty to rename his (Elliot's) species. Frechkop (1943), normally the most cautious of zoologists, did exactly what Elliot had anticipated (Groves 1985).
The type locality given is "Gabon: delta de Rembo Nkomi, au sud de Fernan Vaz" (south of Fernan Vaz or Omboué, which lies 1° 34' S, 9° 15' E). In the Petit Loango Reserve (Loango National Park), south of the type locality, Furuichi et al. (1997) conducted a gorilla survey in 1995. They found gorillas there, although in low density; they attribute this to the low density of herbaceous food.

Gorilla gorilla diehli, Cross River Gorilla
Gorilla diehli Matschie, 1904. The type specimen, an adult male, is in the Berlin Natural History Museum (no. 12789). The skull is only 300 mm long, but this is in fact fairly large for this subspecies, which is the smallest taxon of gorilla.
It was collected at "Dakbe, Kamerun", which is nowadays pronounced "Takpe" (or Nfakwe) and lies at the southern edge of the Takamanda Forest Reserve (6° 2' N, 9° 25' E).
In the Cross River area at the border between Nigeria and Cameroon gorillas still live in several small populations. Sunderland-Groves & Oates (2003) made surveys in the Takamanda Forest Reserve recently and found one gorilla population very close to Takpe.

Gorilla beringei beringei, Mountain Gorilla
Gorilla beringei Matschie, 1903. The type specimen (a young adult male) is in the Berlin Natural History Museum (no. 13254). It was killed by Capt. Robert von Beringe on the "Kirunga ya Sabinyo, 3000 m hoch" (at an altitude of 3,000 m; about 1° 26' S, 29° 37' E). Von Beringe climbed Sabinyo from the side that is now in Uganda.
The most recent gorilla census was conducted in 2003 and confirmed the continuing increase of the population. Several groups range on Mt. Sabinyo; one of them is the Habinyanja group.

Gorilla beringei mikenensis Lönnberg, 1917. The type specimen (an adult male) is no. 5/37 in the Svenska Naturhistoriska Riksmuseet (Stockholm Natural History Museum). It was collected by Captain Elias Arrhenius in the bamboo forest of Mt. Mikeno. Though fully mature, the skull is rather small for a mountain gorilla, only 309 mm in total length.
A photo of Mikeno that Lönnberg included in his publication shows a view from the west. Bamboo grew on the western slopes during Schaller's study in the 1950s (Schaller 1963) and is still growing in certain areas, therefore it is likely that Arrhenius climbed Mikeno from the west.
The remaining bamboo forest on the western slope of Mt. Mikeno does not lie within the distribution area of the Congolese mountain gorillas. If the encroachment stops and the habitat remains suitable for gorillas, they may spread back into the area.

Gorilla beringei graueri Grauer's Gorilla or Eastern Lowland Gorilla
Gorilla graueri Matschie, 1914. The type specimen, an adult male, is in the Berlin Natural History Museum (no. 31618/31619). The skull is rather small in size, only 306 mm long.
It was collected "80 km nordwestlich von Boko am Westufer des Tanganjika" (80 km northwest of Boko on the western shore of Lake Tanganyika), between 2,000 and 3,000 m. On the skull, the inscription says also "Nähe des Nutamba-Flusses" (near the river Nutamba). Possibly it was the river Mutambala.
On an old map dated 1912 (Andrees Handatlas) there is only one "Boko" on the western shore of Lake Tanganyika (at 5° 5' S, 29° 4' E). 80 km northwest of that place leads one to the extreme south of the Itombwe Massif. It is unknown whether gorillas live there nowadays, a new census confirmed them only further north. Doumenge (1998) found no primary forest remaining in the area that Matschie gave as the type locality. According to Eerens et al. (n. d.), there is a little rain forest patch left in the area, but no signs of gorilla presence are known. Even Schaller (1963) did not find gorillas there. In other areas of the Itombwe Forest, gorillas are still present in several populations according to a new census.

Gorilla gorilla rex-pygmaeorum Schwarz, 1927. The type specimen is a young adult male skull and skin in the Tervuren Museum, Belgium (no. 8187).
It was collected in "Luofu, à l'ouest du Lac Albert" (Luofu, west of Lake Albert; 0° 37' S, 29° 7' E). The skull is 305 mm long, about average for its age.
According to Eerens et al. (n. d.), there is no primary forest left in the immediate vicinity of Luofu. Schaller (1963) indicated in his map that the montane forest started north of Luofu, but that gorilla distribution started even further north. Since then, the deforestation has continued, and gorillas live in only a few areas where forest has remained.

A Little History of Gorilla Taxonomy
Thomas Savage called the gorilla Troglodytes gorilla. The genus Troglodytes had first been described, by Étienne Geoffroy Saint-Hilaire, for the chimpanzee; when, over half a century later, it was realised that this generic name had been assigned to quite a different animal - the wren! - 6 years earlier, it had to be changed (the names Anthropopithecus and Simia were in common use until Elliot [1912] instituted the use of Pan Oken, 1816). Isidore Geoffroy Saint-Hilaire transferred the gorilla to a new genus, Gorilla, in 1852. According to Elliot (1912), Rothschild in his publication of 1905 was the first one to use the name Gorilla gorilla, but we have found an earlier use of this combination - Forbes (1895).
The first one who clearly distinguished two forms of gorillas - the western and the eastern gorilla - was Coolidge (1929): "By way of summary, the following important measurements indicate a division into two groups ... Gorilla gorilla gorilla from the coast and Gorilla gorilla beringei found in the mountains of the eastern Congo". Even today, experts do not totally agree on gorilla taxonomy: while some recognise only one gorilla species - with 4 subspecies - (Tuttle 2003), most people working with gorillas now distinguish two species, each with two subspecies.
Although large parts of the original gorilla distribution area have been deforested already, gorillas still live in or near all the places where the type specimens were collected. They even have been confirmed recently in areas where they never were found before, especially in western Cameroon - even though most type specimens are from various parts of Cameroon. Surveys also showed, however, that they are threatened by various factors almost everywhere and only will be able to survive if they are protected efficiently.
If a new gorilla subspecies would be described today, the procedure of description would be essentially the same as in the 19th century. But the form would certainly be different.

Angela Meder and Colin P. Groves

Many thanks to everybody who helped to collect all the information necessary for this overview: Tom Butynski, Fritz Dieterlen, John Hart, Pierre Kakule, Innocent Liengola, Leonard Mubalama, John Oates, Sabine Petri, Tamar Ron, Hendrik Turni

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Additional references
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Dr. Angela Meder studied the behaviour and development of captive lowland gorillas for 10 years. Today she works as a book editor. Since 1992 she has been on the Board of Directors of Berggorilla & Regenwald Direkthilfe.
Prof. Colin Groves wrote his PhD thesis on gorilla osteology and taxonomy. After working at American and British universities, he emigrated to Australia in 1974. He now teaches primatology and human evolution at the Australian National University, and does research on various animals.

Gorillas in general - overview

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