The Barbary macaque (Macaca sylvanus), also known as Barbary ape or magot, is a macaque species native to the Atlas Mountains of Algeria, Libya, Tunisia and Morocco, along with a small introduced population in Gibraltar.
|Young Barbary macaque with its mother|
|Native Range in Red (Northeast Africa); Introduced Range in Violet (Gibraltar)|
Simia sylvanus Linnaeus, 1758
The Barbary macaque is of particular interest because males play an atypical role in rearing young. Because of uncertain paternity, males are integral to raising all infants. Generally, Barbary macaques of all ages and sexes contribute in alloparental care of young.
The diet of Barbary macaque consists primarily of plants and insects and they are found in a variety of habitats. Males live to around 25 years old while females may live up to 30 years. Besides humans, they are the only free-living primates in Europe. Although the species is commonly referred to as the "Barbary ape", the Barbary macaque is actually a true monkey. Its name refers to the Barbary Coast of Northwest Africa.
The population of the Barbary macaques in Gibraltar is the only one outside Northern Africa and the only population of wild monkeys in Europe. Barbary macaques were once widely distributed in Europe, as far north as Norfolk, England, from the Zanclean to the Late Pleistocene. About 300 macaques live on the Rock of Gibraltar. This population appears to be stable or increasing, while the North African population is declining.
History, taxonomy, and phylogenyEdit
The Barbary macaque is first described in scientific literature by Aristotle in the fourth century BCE work History of Animals. He writes of an ape, "Πίθηκος" (//), with "arms like a man, only covered with hair", "feet [which] are exceptional in kind ... like large hands", and "a tail as small as small can be, just a sort of indication of a tail". It is likely that Galen (129–c.216) dissected the Barbary macaque in the second century CE, presuming the internal structure to be the same as a human. Such was the authority of his work, some mistakes he made were not corrected until Andreas Vesalius (1514–1564) proved otherwise over a thousand years later. The Barbary macaque was included in the grouping Simia by Conrad Gessner in his 1551 work Historia Animalium, a name which he claimed was already in use by the Greeks. Gessner's Simia was subsequently used as one of Carl Linnaeus' four primate genera when he published Systema Naturae in 1758. Linnaeus proposed the scientific name Simia sylvanus for the Barbary macaque. During the next 150 years primate taxonomy was subject to great changes and the Barbary macaque was placed in over thirty different taxa. The confusion over the use of Simia became so great that the International Commission on Zoological Nomenclature (ICZN) suppressed its use in 1929. This meant the Barbary macaque was placed in the next oldest genus assigned to it, Macaca, described by Bernard Germain de Lacépède in 1799.
The Barbary macaque is the most primitive macaque species, meaning it is genetically closest to the ancestral form of all macaques. Phylogenetic and molecular analyses show it is a sister group to all macaque species in Asia. The results of a phylogenetic analysis show that the chromosomes of Barbary macaque resemble those of the rhesus macaque with the exception of chromosomes 1, 4, 9, and 16. It was also discovered that chromosome 18 the Barbary macaque is homologous to chromosome 13 in humans.
Polymerase chain reaction studies have found Alu element insertions, small pieces of genetic code in genomes, can infer primate phylogenetic relationships. Using this method the phylogenetic relationship of ten species within the genus Macaca has been resolved, showing the Barbary macaque to be a sister group to all other macaques.
|Phylogeny of ten species of Macaca|
Barbary macaque fossils have been found across Europe, from the Atlantic Ocean to the Black Sea, dating from the Early Pliocene to the Late Pleistocene, assigned to various subspecies including M. s. sylvanus, M. s. pliocena and M. s. florentina. The insular dwarf M. majori endemic to Sardinia-Corsica during the Early Pleistocene, usually considered to have derived from M. sylvanus, is generally considered a distinct species. Remains from Norfolk, England, dating to the Middle Pleistocene, at 53 degrees latitude, are amongst the northernmost records of primates. The youngest known remains of Barbary macaques in Europe are from Hunas, Bavaria, Germany, dated to sometime between 85 and 40,000 years ago. The distribution of Barbary macaques in Europe was likely strongly controlled by climate, only extending into Northern Europe during interglacial intervals.
The Barbary macaque has a dark pink face with a pale buff to golden brown to grey pelage and a lighter underside. The colour of mature adults changes with ages. In adults and subadults the fur on the back is variegated pale and dark which is due to banding on individual hairs. In spring to early summer, as the temperatures rise, the adult macaques moult their thick winter fur. The species shows sexual dimorphism with males larger than females. The mean head-body length is 55.7 cm (21.9 in) in females and 63.4 cm (25.0 in) in males. The boneless vestigial tail is greatly reduced compared with other macaque species and, if not absent, measures 4–22 mm (0.16–0.87 in). Males may have a more prominent tail, though data is scarce. The average body weight is 9.9–11 kg (22–24 lb) in females and 14.5–16 kg (32–35 lb) in males.
Like all Old World monkeys the Barbary macaque well-developed sitting pads (ischial callosities) on its rear. Females exhibit an exaggerated anogenital swelling, which increases in size during oestrus. It has cheek pouches and high-crowned bilophodont molars (molars with two ridges); the third molar is elongated. The diploid chromosome number of the Barbary macaque is 42, like other members of the Old World monkey tribe Papionini.
Distribution and habitatEdit
The Barbary macaque is the only macaque species found outside Asia, and only African primate that survives north of the Sahara Desert. It lives mainly in fragmented areas of the Rif and the Middle and High Atlas mountain ranges of Morocco and the Grande and Petite Kabylie mountain region of Algeria. It has been recorded at altitudes of 400–2300 metres, though it seems to prefer higher elevations. The Moroccan and Algerian populations are around 700 km (430 mi) apart, although the gap was smaller during the Holocene.
Barbary macaques also occur in the British Overseas Territory of Gibraltar at the southern tip of Europe's Iberian Peninsula. Spanish historian from Gibraltar Alonso Hernández del Portillo noted in the early 17th century that the macaques had been present "from time immemorial". Most likely, the Moors introduced macaques from North Africa to Gibraltar during the Middle Ages. During World War II, British Prime Minister Winston Churchill ordered for more Barbary macaques to be introduced to Gibraltar to reverse population declines. Today, there are around 300 Barbary macaques in Gibraltar.
It can live in a variety of habitats, such as cedar, fir, and oak forests, grasslands, thermophilous scrub, and rocky ridges full of vegetation. The climate is Mediterranean and has seasonal extremes of temperature. In Morocco, most Barbary macaques inhabit Atlas cedar (Cedrus atlantica) forests, but this could reflect the present habitat availability rather than a specific preference for this habitat. In Algeria, the Barbary macaque is found mainly in Grande and Petite Kabylie, ranges that form part of the Tell Atlas mountain chain, but there is also an isolated population in Chréa National Park. It is found in mixed cedar and holm oak forests, humid Portuguese and cork oak forests, and scrub-covered gorges.
Fossil evidence indicates the species inhabited Southern Europe and all of North Africa. Historically, it was found across North Africa from Libya to Morocco. A Tunisian population was mentioned in the works of ancient Greek writer Herodotus (ca. 484–425 BCE), indicating the species has become extinct there within the last 2,500 years.
Behaviour and ecologyEdit
The Barbary macaque is gregarious, forming mixed groups of several females and males. Troops can have 10 to 100 individuals and are matriarchal, with their hierarchy determined by lineage to the lead female. Unlike other macaques, the males participate in rearing the young. Males may spend a considerable amount of time playing with and grooming infants. In this way, a strong social bond is formed between males and juveniles, both the male's own offspring and those of others in the troop. This may be a result of selectivity on the part of the females, who may prefer highly parental males.
The mating season runs from November through March. The gestation period is 147 to 192 days, and females usually have only one offspring per pregnancy. Females rear twins in rare instances. Offspring reach maturity at three to four years of age, and may live for 20 years or more.
Grooming other Barbary macaques leads to lower stress levels for the individuals that do the grooming. While stress levels do not appear to be reduced in animals that are groomed, grooming more individuals leads to even lower stress levels; this is a benefit that might outweigh the costs to the groomer, which include less time to participate in other activities such as foraging. The mechanism for reducing stress may be explained by the social relationships (and support) that are formed by grooming.
Male Barbary macaques interfere in conflicts and form coalitions with other males, usually with related males rather than with unrelated males. These relationships suggest that males do so in order to indirectly increase their own fitness. Furthermore, males form coalitions with closely related kin more often than they do with distantly related kin. These coalitions are not permanent and may change frequently as male ranking within the group changes. Although males are more likely to form coalitions with males who have helped them in the past, this is not as important as relatedness in determining coalitions. Males avoid conflicting with higher ranking males and will more frequently form coalitions with the higher ranking male in a conflict. Close grouping of males occur when infant Barbary macaques are present. Interactions between males are commonly initiated when a male presents an infant macaque to an adult male who is not caring for an infant, or when an unattached male approaches males who are caring for infants. This behaviour leads to a type of social buffering, which reduces the number of antagonistic interactions among males in a group.
An open mouth display by the Barbary macaque is used most commonly by juvenile macaques as a sign of playfulness.
The main purpose of calls in Barbary macaques is to alert other group members to possible dangers such as predators. Barbary macaques can discriminate calls by individuals in their own group from those by individuals in other groups of conspecific macaques. Neither genetic variation nor habitat differences are likely causes of acoustic variation in the calls of different social groups. Instead, minor variations in acoustic structure among groups similar to the vocal accommodation seen in humans are the likely cause. However, acoustic characteristics such as pitch and loudness are varied based on the vocalizations of individuals they associate with, and social situations play a role in the acoustic structure of calls.
Barbary macaque females have the ability to recognize their own offspring's calls through a variety of acoustic parameters. Because of this, infant calls do not have to differ dramatically for mothers to be able to recognize their own infant's call. Mothers demonstrate different behaviours on hearing the calls of other infant macaques as opposed to the calls of their own offspring. More parameters for vocalizations lead to more reliable identification of calls in both infants and in adult macaques so it is not surprising that the same acoustic characteristics that are heard in infant calls are also heard in adult calls.
Although Barbary macaques are sexually active at all points during a female's reproductive cycle, male Barbary macaques determine a female's most fertile period by sexual swellings on the female. Mating is most common during a female's most fertile period. The swelling size of the female reaches a maximum around the time of ovulation, suggesting that size helps a male predict when he should mate. This is further supported by the fact that male ejaculation peaks at the same time that female sexual swelling peaks. Change in female sexual behaviour around the time of ovulation is insufficient to demonstrate to the male that the female is fertile. The swellings, therefore, appear necessary for predicting fertility.
Barbary macaque females differ from other nonhuman primates in that they often mate with a majority of the males in their social group. While females are active in choosing sexual associations, the mating behaviour of macaque social groups is not entirely determined by female choice. These multiple matings by females decrease the certainty of paternity of male Barbary macaques and may lead them to care for all infants within the group. For a male to ensure his reproductive success, he must maximize his time spent around the females in the group during their fertile periods. Injuries to male macaques peak during the fertile period, which points to male-male competition as an important determinant of male reproductive success. Not allowing a female to mate with other males, however, would be costly to the male, since doing so would not allow him to mate with more females.
Unlike other macaques where most parental care comes from the mother, Barbary macaques from all age and sex groups participate in alloparental care of infants. Male care of infants has been of particular interest to research because high levels of care from males are uncommon in groups where paternity is highly uncertain. Males even act as true alloparents of infant macaques by carrying them and caring for them for hours at a time as opposed to just demonstrating more casual interactions with the infants. Female social status plays a role in female alloparental interactions with infants. Higher-ranking females have more interactions, whereas younger, lower-ranking females have less access to infants.
The diet of the Barbary macaque consists of a mixture of plants and insect prey. It consumes a large variety of gymnosperms and angiosperms. Almost every part of the plant is eaten, including flowers, fruits, seeds, seedlings, leaves, buds, bark, gum, stems, roots, bulbs, and corms. Common prey caught and consumed by Barbary macaques are snails, earthworms, scorpions, spiders, centipedes, millipedes, grasshoppers, termites, water striders, scale insects, beetles, butterflies, moths, ants, and even tadpoles.
Barbary macaques can cause major damage to the trees in their prime habitat, the Atlas cedar forests in Morocco. Since deforestation in Morocco has become a major environmental problem in recent years, research has been conducted to determine the cause of the bark stripping behaviour demonstrated by these macaques. Cedar trees are also vital to this population of Barbary macaques as an area with cedars can support a much higher density of macaques than one without them. A lack of a water source and exclusion of monkeys from water sources are major causes of cedar bark stripping behaviour in Barbary macaques. Density of macaques, however, is less correlated with the behaviour than the other causes considered.
Their main predators are leopards, eagles (golden eagles may only predate on cubs, since they are not morphologically adapted to hunt primates; other birds of prey that do kill monkeys, like the crowned eagle, live in more southern areas of Africa), and domestic dogs. The approach of eagles and domestic dogs is known to elicit an alarm call response.
Wild populations of Barbary macaques have suffered a major decline in recent years to the point of being declared an endangered species on the IUCN Red List since 2008. The Barbary macaque is threatened by fragmentation and degradation of forest habitat and poaching for the illegal pet trade, and it is killed in retaliation for raiding crops.
Spain is the main entry point in Europe. Today, no accurate data exist on the location and number of individuals out of their habitat. An unknown number of individuals is included in zoological collections, at other institutions, in private hands, in storage, or waiting to be relocated to appropriate destinations.
The habitat of the Barbary macaque is under threat from increased logging activity. Local farmers view the monkeys as pests, and engage in extermination of the species. Once common throughout northern Africa and southern Europe, only an estimated 12,000 to 21,000 Barbary macaques are left in Morocco and Algeria. Once, their distribution was much more extensive, reaching Tunisia and Libya. Their range is no longer continuous, with only isolated areas of range remaining. During the Pleistocene, this species inhabited the Mediterranean coasts and Europe, reaching Italy, Hungary, Spain, Portugal, and France, and as far north as Germany and the British Isles. The species decreased with the arrival of the Ice Age, becoming extinct in the Iberian Peninsula 30,000 years ago.[clarification needed]
The Barbary macaque is threatened by habitat loss, overgrazing, and illegal capture. In Morocco, tourists interact with Barbary macaques in many regions. Information collected in the interviews with inhabitants in the High Atlas of Morocco indicated that the capture of macaques occurs in these regions. Conflict between local people and wild macaques is one of the greatest challenges to Barbary macaque conservation in Morocco. The main threats to the survival of Barbary macaques in this region have been found to be habitat destruction and the impact of livestock grazing, but problems of conflict with inhabitants are also increasing due to crop raiding and the illegal capture of macaques. Human–macaque conflict is mainly due to crop raiding. In the High Atlas of Morocco, macaques attract a large number of tourists every year, and they are favoured for their potential benefits to tourism. In addition, macaques have some ecological roles; for example, they are the predators of several destructive insects and pests of plants and participate in seed dispersal in many plant species.
In the Central High Atlas, the Barbary macaque occurs in relatively small and fragmented areas restricted to the main valleys at altitudes of 700–2,400 m. In a 2013 study, researchers reported that they found Barbary macaques in relatively small and fragmented habitats in 10 sites, and that the species no longer occurred in four localities. This could be attributed to habitat degradation, hunting activities, the impact of livestock grazing, and disturbance by people. As deforestation for agriculture and overgrazing continues, the remaining forest becomes increasingly fragmented. Consequently, the Barbary macaque is now restricted to small, fragmented relict habitats.
Human use and tourismEdit
Many of the mistaken ideas about human anatomy contained in the writings of Galen are apparently due to his use the Barbary macaque, the only anthropoid available to him, in dissections. Strong cultural taboos of his time prevented his performing any actual dissections of human cadavers, even in his role as physician and teacher of physicians.
Macaques in Morocco are frequently used as photo props, despite their protected status. Tourists are encouraged to take photos with the animals for a fee. Macaques are also sold as pets in Morocco and Algeria, and exported to Europe to be used as pets and fighting monkeys, both in physical marketplaces and online.
Tourists interact with wild monkeys across the globe, and in some situations, tourists may be encouraged to feed, photograph, and touch the monkeys. Although tourism has the potential to bring in money towards conservation goals and provides an incentive for the protection of natural habitats, close proximity and interactions with tourists can also have significant psychological impacts on the Barbary macaques. Fecal samples and stress-indicating behaviours, such as belly scratching, indicate that the presence of tourists has a negative impact on the macaques. Human activities such as taking photographs cause the animals stress, possibly because the people come too close to the animals and make prolonged eye contact (a sign of aggression in many primates). Macaques that live in areas close to human contact have more parasites and lower overall health than those that live in wilder environments, at least in part due to the unhealthy diets they receive as a result of feeding from humans.
Several groups of Barbary macaques can be found in tourist sites, where they are affected by the presence of visitors providing food to them. Researchers comparing two such groups in the central High Atlas mountains in 2008 found that the tourist group of Barbary macaques spent significantly more time engaged in resting and aggressive behaviour, and foraged and moved significantly less than the wild group. The tourist group spent significantly less time per day feeding on herbs, seeds, and acorns than the wild group. Human food accounted for 26% of the daily feeding records for the tourist group, and 1% for the wild-feeding group. Scientists who collected data on the seasonal activity budget and diet composition of the endangered Barbary macaque group inhabiting a tourist site in Morocco found that activity budgets and diet of the study group varied markedly among seasons and habitats. The percentage of daily time spent in foraging and moving was lowest in spring, and the daily time spent in resting was highest in spring and summer. The time budget devoted to aggressive display was highest in spring than the other three seasons. There is an increase in the daily feeding time spent eating flowers and fruits in summer, seeds, acorns, roots and barks in winter and autumn, herbs in spring and summer, and a clear increase in consumption of the human food in spring. The tourist and the wild groups did not differ in the proportion of daily records devoted to terrestrial feeding, but the tourist group spent a significantly lower percentage of daily records in terrestrial foraging, moving and resting, while performing more terrestrial aggressive displays more than the wild group. There was no significant difference between the two groups in the proportion of terrestrial feeding records spent eating fruits; but the tourist group had lower daily percentages of terrestrial feeding on leaves, seeds and acorns, roots and barks, and herbs, while it spent higher daily percentages of terrestrial feeding on human food.
There is evidence that Barbary macaques were traded or perhaps given as diplomatic gifts as long ago as the Iron Age. Their remains have been found in such sites as Emain Macha in Ireland, dating to no later than 95 BC; an Iron Age hillfort, the Titelberg in Luxembourg; and two Roman sites in Britain.
- Groves, C. P. (2005). "Species Macaca sylvanus". In Wilson, D. E.; Reeder, D. M (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. p. 164. ISBN 978-0-8018-8221-0. OCLC 62265494.
- Wallis, J.; Benrabah, M.E.; Pilot, M.; Majolo, B.; Waters, S. (2020). "Macaca sylvanus". IUCN Red List of Threatened Species. 2020: e.T12561A50043570. doi:10.2305/IUCN.UK.2020-2.RLTS.T12561A50043570.en. Retrieved 17 January 2022.
- Linnaeus, C. (1758). "Simia sylvanus". Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Vol. I (Decima, reformata ed.). Holmiæ: Laurentii Salvii. p. 25.
- "Macaca sylvanus". Integrated Taxonomic Information System. Retrieved 22 September 2021.
- Small, M. F. (1990). "Alloparental behaviour in Barbary macaques, Macaca sylvanus". Animal Behaviour. 39 (2): 297–306. doi:10.1016/s0003-3472(05)80874-7. S2CID 53192425.
- Rathke, E. -M.; Berghänel, A.; Bissonnette, A.; Ostner, J.; Schülke, O. (2017). "Age-dependent change of coalitionary strategy in male Barbary macaques". Primate Biology. 4 (1): 1–7. doi:10.5194/pb-4-1-2017. PMC 7041515. PMID 32110686.
- Fooden, J. (2007). Systematic review of the Barbary macaque, Macaca sylvanus (Linnaeus, 1758). New series No. 113. Chicago: Field Museum of Natural History.
- Elton, Sarah; O'Regan, Hannah J. (2014). "Macaques at the margins: the biogeography and extinction of Macaca sylvanus in Europe" (PDF). Quaternary Science Reviews. 96: 117–130. Bibcode:2014QSRv...96..117E. doi:10.1016/j.quascirev.2014.04.025.
- McDermott, W. C. (1938). The apes in antiquity. Baltimore: Johns Hopkins University Press. pp. 88–100.
- Stiles, Charles Wardell; Orleman, Mabelle Blanche (1927). The nomenclature for man, the chimpanzee, the orang-utan, and the Barbary ape. U.S. Government Printing Office. pp. 3–10.
- Li, Jing; Han, Kyudong; Xing, Jinchuan; Kim, Heui-Soo; Rogers, Jeffrey; Ryder, Oliver A.; Disotell, Todd; Yue, Bisong; Batzer, Mark A. (2009). "Phylogeny of the macaques (Cercopithecidae: Macaca) based on Alu elements". Gene. 448 (2): 242–249. doi:10.1016/j.gene.2009.05.013. PMC 2783879. PMID 19497354.
- Hodges, J. K.; Cortes, J. (2006). The Barbary macaque: biology, management and conservation. Nottingham, UK: Nottingham University Press.
- Waters, S. S. (2013). "Family Cercopithecidae: Old World monkeys". In Mittermeier, Russell A.; Rylands, Anthony B.; Wilson, Don E. (eds.). Handbook of the mammals of the world. Volume 3. Primates. Barcelona: Lynx Edicions. pp. 550–639. ISBN 978-84-96553-89-7.
- Fleagle, John G. (2013). Primate adaptation and evolution (3rd ed.). Amsterdam: Elsevier/Academic Press. ISBN 9780123786326. OCLC 820107187.
- Kuester, J.; Paul, A. (1984). "Female reproductive characteristics in semifree-ranging Barbary macaques (Macaca sylvanus L. 1758)". Folia Primatologica. 43 (2–3): 69–83. doi:10.1159/000156173. PMID 6519600.
- Taub, D. M. (1978). "The Barbary macaque of North Africa". Oryx. 14 (3): 245–253. doi:10.1017/S0030605300015581.
- Möhle, U.; Heistermann, M.; Dittami, J.; Reinberg, V.; Hodges, J. K.; Hodges, J. K. (2005). "Patterns of anogenital swelling size and their endocrine correlates during ovulatory cycles and early pregnancy in free-ranging barbary macaques (Macaca sylvanus) of Gibraltar". American Journal of Primatology. 66 (4): 351–368. doi:10.1002/ajp.20161. PMID 16104035. S2CID 19899619.
- Brauch, Katrin; Pfefferle, Dana; Hodges, Keith; Möhle, Ulrike; Fischer, Julia; Heistermann, Michael (2007). "Female sexual behavior and sexual swelling size as potential cues for males to discern the female fertile phase in free-ranging Barbary macaques (Macaca sylvanus) of Gibraltar". Hormones and Behavior. 52 (3): 375–383. doi:10.1016/j.yhbeh.2007.06.001. PMID 17644098. S2CID 30650507.
- Nosowitz, D. (2019). "The Curious Case of the Last 'Wild' Monkeys in Europe". Atlas Obscura. Retrieved 2022-04-03.
- Jackson, W.G.F. (1987). "1. Mons Calpe to Djebel Musa". The Rock of the Gibraltarians – A History of Gibraltar. Fairleigh Dickinson University Press. p. 28. ISBN 0-8386-3237-8.
- Taub, David Milton (1977). "Geographic distribution and habitat diversity of the Barbary macaque Macaca sylvanus L.". Folia Primatologica. 27 (2): 108–133. doi:10.1159/000155781. PMID 403111.
- Deag, J. M (1980). "Interactions between males and unweaned Barbary macaques: testing the agonistic buffering hypothesis". Behaviour. 75 (1): 54–80. doi:10.1163/156853980x00564.
- Kuester, J. (1999). "Male migration in Barbary macaques at Affenberg Salam". International Journal of Primatology. 20 (1): 85–106. doi:10.1023/A:1020536317646. S2CID 43112228.
- Shutt, K.; MacLarnon, A.; Heistermann, M.; Semple, S. (2007). "Grooming in Barbary macaques: better to give than to receive?". Biology Letters. 3 (3): 231–233. doi:10.1098/rsbl.2007.0052. PMC 2464693. PMID 17327200.
- Widdig, A.; Streich, W. J.; Tembrock, G. (2000). "Coalition formation among male Barbary macaques (Macaca sylvanus)". American Journal of Primatology. 50 (1): 37–51. doi:10.1002/(sici)1098-2345(200001)50:1<37::aid-ajp4>3.3.co;2-v. PMID 10588434.
- Preuschoft, S. (1992). ""Laughter" and "smile" in Barbary macaques (Macaca sylvanus)". Ethology. 91 (3): 220–236. doi:10.1111/j.1439-0310.1992.tb00864.x.
- Fischer, J.; Hammerschmidt, K.; Todt, D. (1998). "Local variation in Barbary macaque shrill barks". Animal Behaviour. 56 (3): 623–629. doi:10.1006/anbe.1998.0796. PMID 9784211. S2CID 6947829.
- Fischer, J.; Hammerschmidt, K. (2002). "An overview of the Barbary macaque, Macaca sylvanus, vocal repertoire". Folia Primatologica. 73 (1): 32–45. doi:10.1159/000060417. PMID 12065939. S2CID 9791964.
- Hammerschmidt, K.; Todt, D. (1995). "Individual differences in vocalisations of young Barbary macaques (Macaca sylvanus): a multi-parametric analysis to identify critical cues in acoustic signalling". Behaviour. 132 (5): 381–399. doi:10.1163/156853995x00621.
- Kuester, J.; Paul, Andreas (1992). "Influence of male competition and female mate choice on male mating success in Barbary macaques". Behaviour. 120 (3/4): 192–216. doi:10.1163/156853992x00606. JSTOR 4535008.
- Ciani, A. C.; Camperio, A.; Martinoli, L.; Capiluppi, C.; Arahou, M.; Mouna, M. (2001). "Effects of water availability and habitat quality on barkstripping behavior in Barbary macaques". Conservation Biology. 15 (1): 259–265. doi:10.1111/j.1523-1739.2001.99019.x. S2CID 86080812.
- Bautista, J. (2018). "Golden eagles (Aquila chrysaetos) as potential predators of Barbary macaques (Macaca sylvanus) in northern Morocco: evidences of predation". Go-South Bull. 15n: 172–179.
- van Uhm, D. P. (2016). "Monkey business: the illegal trade in Barbary macaques". Journal of Trafficking, Organized Crime and Security. 2 (1): 36–49. hdl:1874/358227.
- van Lavieren, E.; Wich, S. A. (2010). "Decline of the endangered Barbary macaque in the cedar forest of the Middle Atlas Mountains, Morocco". Oryx. 44 (1): 133–138. doi:10.1017/s0030605309990172.
- Von Segesser, F.; Menard, N.; Gaci, B.; Martin, R. D. (1999). "Genetic differentiation within and between isolated Algerian subpopulations of Barbary macaques: evidence from microsatellites". Molecular Ecology. 8 (3): 433–442. doi:10.1046/j.1365-294x.1999.00582.x. PMID 10199007. S2CID 23657621.
- O'Reagan, H. (2008). "The Iberian Peninsula- corridor or cul-de-sac? Mammalian faunal change and possible routes of dispersal in the last 2 million years". Quaternary Science Reviews. 27 (23–24): 2136–2144. Bibcode:2008QSRv...27.2136O. doi:10.1016/j.quascirev.2008.08.007.
- El Alami, A.; Van Lavieren, E.; Aboufatima, R.; Chait, A. (2013). "A survey of the endangered Barbary macaque Macaca sylvanus in the central High Atlas Mountains, Morocco". Oryx. 47 (3): 451–456. doi:10.1017/s0030605311001463.
- El Alami, A.; Chait, A. (2012). "Seasonal variation in activity budget and diet of the endangered Macaca sylvanus in the tourist valley of Ouzoud, Central High Atlas, Morocco". Mammalia. 76: 245–250. doi:10.1515/mammalia-2011-0054. S2CID 87795900.
- El Alami, A.; Van Lavieren, E.; Aboufatima, R.; Chait, A. (2012). "Differences in activity budgets and diet between semiprovisioned and wild-feeding groups of the endangered Barbary macaque (Macaca sylvanus) in the Central High Atlas Mountains, Morocco". American Journal of Primatology. 74 (3): 210–216. doi:10.1002/ajp.21989. PMID 24006539. S2CID 18223816.
- El Alami, A.; Chait, A. (2013). "Comparison of the terrestriality of Barbary macaques (Macaca sylvanus) between tourist and wild sites in the region of Ouzoud, Morocco". Mammalia. 78 (4): 539–542. doi:10.1515/mammalia-2013-0061. S2CID 87021869.
- El Alami, A.; Chait, A. (2014). "Distribution of the endangered Barbary macaque and human-macaque interaction in the tourist region of Ouzoud, central High Atlas of Morocco". African Journal of Ecology. 53 (3): 375–377. doi:10.1111/aje.12191.
- El Alami, A.; Chait, A. (2015). "Roles of tourism in the local people opinion regarding human-macaque conflict in the central High Atlas, Morocco". Revue de Primatologie. 7: 1–7.
- Ustun, C. (2004). "Galen and his anatomic eponym: vein of Galen". Clinical Anatomy. 17 (6): 454–457. doi:10.1002/ca.20013. PMID 15300863.
- Arnold, T. (1932). "Law enforcement: an attempt at social dissection". The Yale Law Journal. 42 (1): 1–24. doi:10.2307/791414. JSTOR 791414. S2CID 150797237.
- Nijman, V.; Bergin, D.; van Lavieren, E. (2015). "Barbary macaques exploited as photo-props in Marrakesh's punishment square". SWARA (July–September ed.). pp. 38–41.
- Bergin, D.; Atoussi, S.; Nijman, V. (2017). "Online trade of Barbary macaques Macaca sylvanus in Algeria and Morocco" (PDF). Biodiversity and Conservation. 27 (2): 531–534. doi:10.1007/s10531-017-1434-5. S2CID 41616038.
- "Tourists upset Morocco Barbary macaque monkeys". BBC.
- "Monkeys and tourism – a price to pay". Archived from the original on 25 March 2015.
- Lynn, C. (2003). Navan Fort: archaeology and myth. Bray, Co. Wicklow, Ireland: Wordwell. pp. 49–50. ISBN 9781869857677.
- ARKive - images and movies of the Barbary macaque (Macaca sylvanus)
- Chisholm, Hugh, ed. (1911). Encyclopædia Britannica (11th ed.). Cambridge University Press. .