HYBRID PRIMATES

LEMURS

Several lemur species have produced hybrid offspring in captivity. Hybrids of many lemur species were recorded by Gray (1972). The two ruffed lemur species (red and the black & white ruffed lemurs) hybridize fertilely in captivity. Among the other lemuridae, the hybrids have not been recorded as being fertile.

The Black Lemur (Lemur macaco) and Crowned Lemur (Lemur coronatus) do not hybridize in the wild, but produced a confirmed female hybrid in captivity.
S. Warter, Y. Rumpler "Cytogenetic study of a female Lemur coronatus × Lemur macaco hybrid" Faculté de Médecine, Institut d'Embryologie, 67085 Strasbourg Cédex, France

The Brown Lemur (Eulemur fulvus) and Red-bellied Lemur (Eulemur rubriventer) have also produced a hybrid (Asson Zoo)

During the 19th and 20th centuries, it has been suggested that Black-and-White Ruffed Lemurs (Varecia variegata)and Red Ruffed Lemurs (Varecia rubra) hybridize in nature. Although natural hybrid zone has never been documented, this contributed to the two forms being considered subspecies of Varecia variegata. Recent reseearch indicates there is a hybrid zone, but that hybridization is the exception rather than the rule, hence the black-and-white ruffed lemur and the red ruffed lemur were upgraded from subspecies to full species.
N Vasey, I Tattersall "Do Ruffed Lemurs Form a Hybrid Zone? Distribution and Discovery of Varecia, with Systematic and Conservation Implications"

A purported Red-fronted Lemur (Eulemur fulvus rufus) x White-Collared Brown Lemur (E. albocollaris) hybrid zone at Andringitra, Madagascar was examined using DNA studies. When the DNA markers of putative hybrids were examined, 18 of 21 were found to contain markers from both E. albocollaris and E.f. rufus populations. The remaining three individuals were found to contain only markers for E. albocollaris. The results indicate that the population at Andringitra is a hybrid population between the two species. The White Collared Brown Lemur was reclassified as the Gray-headed Lemur (Eulemur cinereiceps) in 2008. The Red-fronted Lemur is now Eulemur rufifrons.
Wyner Yael M; Johnson Steig E; Stumpf Rebecca M; Desalle Rob. "Genetic assessment of a white-collared x red-fronted lemur hybrid zone at Andringitra, Madagascar." American journal of primatology 2002;57(2):51-66.

D. Curtis and A. Zaramody carried out a 10-month study on mongoose lemurs at Anjamena in northwestern Madagascar (Curtis 1997). They observed animals with colouration intermediate between the Mongoose Lemur (E. mongoz) and Red-fronted Lemur (E.f. rufus). This suggested there was a hybrid zone where the two species interbred. This was substantiated by the existence of a Brown lemur that had the mitochondrial (maternal) DNA of a mongoose lemur (Zaramody & Pastorini 2001).
Curtis DJ (1997) The Mongoose Lemur (Eulemur mongoz): A Study in Behaviour and Ecology. Dissertation, Universität Zürich.
Zaramody A & Pastorini J (2001) Indications for hybridisation between red-fronted lemurs (Eulemur fulvus rufus) and mongoose lemurs (E. mongoz) in northwest Madagascar. Lemur News 6:28-31
Pastorini J, Zaramody A, Curtis DJ, Nievergelt CM & Mundy NI (2009) Genetic analysis of hybridization and introgression between wild mongoose and brown lemurs. BMC Evolutionary Biology 9:32

MONKEYS AND APES

In "The Variation Of Animals And Plants Under Domestication" Charles Darwin noted: "Several members of the family of Lemurs have produced hybrids in the Zoological Gardens."

In the primates, many Gibbons are hard to visually identify and are identified by their song. This has led to hybrids in zoos where the Gibbons were mis-identified. For example, some collections could not distinguish between Javan Gibbons, Lar Gibbons or Hoolocks and their supposedly pure breeding pairs were mixed pairs or hybrids from previous mixed pairs. Agile gibbons have also interbred with these. The offspring were sent to other Gibbon breeders and led to further hybridization in captive Gibbons. Hybrids also occur in wild Gibbons where the ranges overlap. Gibbon/Siamang hybrids have occurred in captivity - a female Siamang produced hybrid "Siabon" offspring on 2 occasions when housed with a male Gibbon; one hybrid survived, the other didn't. Anubis Baboons and Hamadryas Baboons have hybridized in the wild where their ranges meet. Different Macaque species can interbreed. In "The Variation Of Animals And Plants Under Domestication" Charles Darwin wrote: "A Macacus, according to Flourens, bred in Paris; and more than one species of this genus has produced young in London, especially the Macacus rhesus, which everywhere shows a special capacity to breed under confinement. Hybrids have been produced both in Paris and London from this same genus." In addition, the Rheboon is a captive-bred Rhesus Macaque/Hamadryas Baboon hybrid with a baboon-like body shape and Macaque-like tail.

Various hybrid monkeys are bred within the pet trade. These include hybrid Capuchins e.g. Tufted (Cebus apella) x Wedge-capped/weeper (C olivaceus); Liontail macaque X Pigtail macaque hybrids and Rhesus x Stumptail hybrids. The Japanese macaque (Macaca fuscata) has interbred with the introduced Taiwanese macacque (M cyclopis); the latter has escaped into the wild from private zoos. Among African monkeys, natural hybridization is not uncommon. There numerous field reports of hybrid monkeys and detailed studies of zones where species overlap and hybrids occur. Among the apes, Sumatran and Bornean orang-utans are separate species with anatomical differences, producing sterile hybrids. Hybrid orang utans are genetically weaker lower survival rates pure animals.

Another unknown ape (the Koolakamba) has been reported in Africa and claimed to be a Gorilla/Chimp hybrid. Larger, flatter faced, larger skulled and more bipedal than a chimp, it may also be a mutation, in which case we are witnessing evolution in action. According to von Koppenfels in 1881: “I believe it is proved that there are crosses between the male Troglodytes gorilla and the female Troglodytes niger, but for reasons easily understood, there are none in the opposite direction. I have in my possession positive proof of this. This settles all the questions about the gorilla, chimpanzee, Kooloo Kamba, N’schigo, M’bouve, the Sokos, Baboos, etc”. Yerkes reported several "unclassifiable apes" with features intermediate between chimpanzee and gorilla in his 1929 book "A Study of Anthropoid Life". In fact most of these are regional races of chimpanzee classified as separate species by over-enthusiastic naturalists.

Above: images of the koolo-kamba, n'schiego mbouve and soko from Cassell's Natural History (1901). These are now considered regional races of chimpanzee.

Garner (1896) wrote that an ape called Mafuca exhibited at Dresden Zoo in 1875 was sometimes described as a cross between chimpanzee and gorilla. Different experts identified her as a chimpanzee or as a young gorilla."It would be difficult to believe that two apes of different species in a wild state would cross, but to believe that two that belonged to different genera would do so is even more illogical. Yerkes (1929) reported the case of adult female Johanna at Lisbon, whom Duckworth (1899) considered an unclassifiable ape intermediate between gorilla and chimpanzee and similar to the “Kulu-Kamba” and Mafuca. Others considered Johanna, who had been a performing ape wit Barnum and Bailey's Circus, to be a gorilla.

HUMANZEES (& OTHER CLAIMED HUMAN HYBRIDS)

A reputed "humanzee" (human/chimp hybrid) called Oliver was DNA tested and found to be a chimpanzee, albeit one which slightly differed genetically from the more familiar chimps in being bipedal and having a smaller head. Oliver may have been a mutant or represent an unknown species of ape. It is currently believed that he represents a geographical subspecies of chimpanzee. He did not associate with other chimps in captivity as was sexually attracted to human women instead. This meant he was never bred. Oliver's habitual bipedal gait is now believed to be a result of early training and habit, although he mastered it to a greater degree than most trained chimps. It's worth remembering that evolution is a never-ending process and that it's possible for bipedalism to develop in other apes. In a publicity event, a woman declared her willingness to be inseminated by Oliver (and even to have the mating filmed for scientific purposes), but this offended public sensibilities and did not happen. Had Oliver been a genuine hybrid, then like most male hybrids he would probably have been sterile anyway.

Soviet Professor Ilya Ivanov attempted to create a human-ape hybrid using female chimps impregnated and human sperm and planned to use women volunteers impregnated with chimp sperm. Ivanov's experiments have been documented by Kirill Rossiianov (Institute for the History of Science and Technology of the Academy of Sciences, Moscow), "Beyond Species: Ilya Ivanov and His Experiments on Cross-Breeding Humans with Anthropoid Apes," Science in Context, 2002, p. 277-316.

In a presentation to the World Congress of Zoologists in Graz in 1910, he outlined the possibility of using artificial insemination to create a hybrid. In 1924, while working at the Pasteur Institute in Paris, Ivanov gained permission from the Institute's directors to use its experimental primate station in Kindia, French Guinea, for his hybridisation experiments. He requested backing for this project from the Soviet government, writing to Soviet officials including the People's Commissar on Education and Science Anatoliy Vasilievich Lunacharsky. In September 1925, Nikolai Petrovich Gorbunov, head of the Department of Scientific Institutions helped allocate US$10000 to the Academy of Sciences for Ivanov's human-ape hybridization experiments in Africa.

In March 1926 Ivanov arrived at the Kindia facility, but left after a month because the facility had no sexually mature chimpanzees. Ivanov attempted to organize the insemination of human females with chimpanzee sperm in Guinea, but the French colonial government objected to the proposal. There is no evidence such an experiment was arranged there. Back in France he corresponded with French Guinea's colonial governor and arranged to conduct his experiments at the botanical gardens in Conakry. Ivanov, assisted by his son (also called Ilya), went to Conakry in November 1926 where he oversaw the capture of adult chimpanzees in the interior of the colony. These were caged at the botanical gardens in Conakry. On February 28, 1927, Ivanov artificially inseminated 2 female chimps with human sperm (not sourced from him or his son). On June 25, he injected a third chimpanzee with human sperm. The Ivanovs left Africa in July 1927 with 13 chimps, including the 3 artificially inseminated females. They already knew that the first 2 chimps had not conceived. The third died in France and was also found not to have conceived. The remaining 10 chimps went to the Sukhumi primate station.

Ivanov returned to the Soviet Union in 1927 and attempted to organize experiments at Sukhumi using ape sperm and human females. In 1929, with the help of Gorbunov, he gained the support of the Society of Materialist Biologists (a group associated with the Communist Academy). In Spring 1929 the Society set up a commission to plan Ivanov's experiments at Sukhumi. They required at least 5 volunteer women for the project. In June 1929, before any inseminations had taken place, the only sexually mature ape remaining at Sukhumi (an orangutan) had died. A new set of chimps would not arrive at Sukhumi until Summer 1930. That year, a political shakeup in the Soviet scientific world resulted in Gorbunov and several other Sukhumi scientists losing their positions. In Spring 1930 Ivanov came under political criticism and on December 13, 1930 he was arrested and exiled to Alma Ata, where he died in 1932.

There have been persistent rumours of a Chinese humanzee experiment; the rumoured 3 month foetus died when the mother was killed during civil unrest. Allegedly scientists impregnated a female chimpanzee with human sperm and she was three months pregnant before people found out; outraged they broke into the lab in a riot, killing the pregnant chimpanzee. This must be treated as urban myth as there is no currently no evidence to support the tale and far to many claims of conspiracy theory cover-ups.

There are similar rumours of a humanzee or manpanzee experiment in the USA. In the 1960s there were persistent rumours of a Russian experiment to inseminate either a female chimpanzee or a female gorilla with human sperm. Bernard Grizmek, former Frankfurt Zoo director, wrote of rumours from the Soviet Union that the Russians had created a human/chimpanzee hybrid (probably a mis-reporting of Ilya Ivanov's experiments). More recently, a news story claimed that Stalin ordered his scientists to create an army of human/ape hybrids, because they would be less fussy about what they ate. Though nothing came of this, it may have been the origin of the rumours.

According to a tale by Peter Damain in the 11th century story “De bono religiosi status et variorum animatium tropolagia,” Count Gulielmus had both a pet ape and a wanton wife. The woman was so wanton that she allowed the ape to become her lover. The ape became jealous of the Count and when it found him lying with the Countess, the ape attacked him. The Count died of his grievous injuries. Damain had learned of this from Pope Alexander II. The pope had shown Damain a monster that was supposedly the result of the ape mating with the woman. This apelike boy was called Maimo after his simian father. If Maimo did exist, he was most likely a physically and mentally handicapped child.

In the 19th century, a Khoisan (Hottentot) woman called Saartjie Baartman was exhibited in Europe in a cage. Negro women with enlarged labia and enlarged buttocks were sometimes deemed evidence of chimp/human hybridisation; such hybrids being called a "womanzee". This was based on the supposed resemblance of their genitalia to those of female chimps and fitted with the then prevalent opinion that Negroes were inferior, or less evolved, than Europeans. Enlarged buttocks occur due to a condition called steatopygia (extreme accumulation of fat on the buttocks), while enlarged labia, or "Hottentot Apron" can be either inherited or induced/enhanced by manual stretching (in some regions they were considered attractive). Neither trait is due to hybridisation.

The idea of human/ape hybrids has fascinated people and resulted in several films or TV series, some exploring whether such hybrids would have "human rights" or simply be experimental animals for use in vivisection. It is only a matter of time before curiosity overcomes ethics and an authenticated attempt is made.

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