Wolfgang Peter Johann Dittus (born 1 June 1943) is a primatologist and behavioral ecologist based in Sri Lanka.
Born in Berlin, Germany, and brought up in the rural Black Forest (German: Schwarzwald) region Baden-Württemberg, Wolfgang 'Wolf' Dittus migrated to Canada in 1953, where he studied geology at McGill University. During this time, however, his interests shifted to psychology and zoology, his early research having been on the song patterns of cardinal birds, inspiring an interest in animal communication in general.
He was awarded a PhD by the University of Maryland in 1974, his doctoral dissertation having been on 'The ecology and behavior of the toque monkey, Macaca sinica', in pursuit of which he moved to Sri Lanka in 1968. [1] This work was conducted largely at a research site established at Polonnaruwa under one of the Smithsonian Institution's projects that commenced in Sri Lanka during the 1960s funded by the United States' Public Law (PL) 480 'Food for Peace' programme. With the phasing out of the Smithsonian's association with this program in 1972, all but Dittus' study on toque macaques came to an end. His PhD research contributed original and seminal discoveries in the fields of behavioral-ecology, population biology and social evolution of primates. [2]
The Sri Lanka primate project still continues, now more than four decades later. It is recognized as being the most intensive long-term study of a wild population of primates, anywhere, ever. [3] Dittus' team tracks (among dozens of other variables) the life histories of some 4,500 macaques from birth to death, maintains matrilineal and patrilineal genealogies, documents migration between troupes and monitors the social rank and relations of each individual through time. His team has been engaged in similar long-term studies on the grey langur (Semnopithecus priam thersites) and the northern purple-faced leaf monkey (Semnopithecus vetulus philbricki) at the same site.
The initiative contributes to the disciplines of sociobiology, forest ecology, population biology, genetics, epidemiology and conservation in these primates. It has up to now generated more than 50 scientific papers[; [4] See Publications below] and is remarkable for its engagement with the local community as well as a large number of students and volunteers―national and international, specialist and lay―over its lifetime. The research has yielded deep insights into the ecology and evolutionary biology not only of primates, but also of social mammals in general. On the premise that public education is basic to nature conservation, Dittus has contributed to many documentary films in international television about the fascinating phenomenon of primate societies. [5] [6] [7]
Wolf Dittus, has two children Thomas and Tatiana, and continues to live and work in Sri Lanka. [8]
1. Dittus, W. P. J. and Lemon, R. E. 1969. Effects of song tutoring and acoustic isolation on song repertoires of cardinals. Animal Behaviour 17, 523-533.
2. Dittus, W. P. J., 1974. The ecology and behavior of the toque monkey, Macaca sinica. Ph.D. Thesis, University of Maryland, Maryland; 55+127+56 pp.
3. Ekanayake, D.K., Welch, R.K., Kieft, R., Hajduk, S. & Dittus, W.P.J. 2007 . Transmission dynamics of Cryprosporidium infection in a natural population of non-human primates at Polonnaruwa. American Journal Tropical Medicine and Hygiene 77(5), 818-822.
4. Dittus, W.P.J. 2004. Demography: a window to social evolution; pp 87–116 in (Thierry, B., Singh, M. & Kaumanns, W., eds.): Macaque societies: A model for the study of social organization, Cambridge University Press, Cambridge.
5. De Silva, A.M., Dittus, W.P.J., Amerasinghe, P.H., et al. 1999. Serologic evidence for an epizootic dengue virus infecting toque macaques (Macaca sinica) at Polonnaruwa, Sri Lanka. American Journal of Tropical Medicine and Hygiene 60(2), 300-306. 6. Dittus, W.P.J. 1998. Birth sex ratios in toque macaques and other mammals: integrating the effects of maternal condition and competition. Behavioral Ecology and Sociobiology, 44: 149-160 .
7. Keane, B., Dittus, W.P.J. and Melnick, D.J. 1997.Paternity assessment in wild groups of toque macaques (Macaca sinica) at Polonnaruwa, Sri Lanka using molecular markers. Molecular Ecology 6(3): 267-282.
8. Hoelzer, G. A., Dittus, W. P. J., Ashley, M. V. et al. 1994. The local distribution of highly divergent mitochondrial-DNA haplotypes in toque macaques (Macaca sinica) at Polonnaruwa, Sri Lanka. Molecular Ecology 3(5), 451-458.
9. Cheverud, J.M., Wilson, P. and Dittus, W.P.J. 1992. Primate population studies at Polonnaruwa. 3. Somatometric growth in a natural population of toque macaques (Macaca sinica). Journal of Human Evolution 23(1), 51-77.
10. Cheverud, J.M. and Dittus, W.P.J. 1992. Primate population studies at Polonnaruwa. 2. Heritability of body measurements in a natural-population of toque macaques (Macaca sinica). American Journal of Primatology 27(2), 145-156.
11. Dittus, W. P. J. 1987. Group fusion among wild toque-macaques - an extreme case of intergroup resource competition. Behaviour 100, 247-291.
12. Dittus, W.P.J. 1986. Sex-differences in fitness following a group take-over among toque macaques - testing models of social evolution. Behavioral Ecology and Sociobiology 19(4): 257-.
13. Dittus, W.P.J. 1985. The influence of cyclones on the dry evergreen forest of Sri Lanka. Biotropica 7(1), 1-14.
14. Dittus, W.P.J. 1984. Toque macaque food calls - semantic communication concerning food distribution in the environment. Animal Behaviour 32, 470-477.
15. Dittus W.P.J. 1980. The social regulation of primate populations: a synthesis; in Lindburg D.G. (ed.), The macaques: studies in ecology, behavior and evolution. Van Nostrand Reinhold, New York, pp 263–286.
16. Dittus, W.P.J. 1979. Evolution of behaviors: regulating density and age-specific sex ratios in a primate population. Behaviour 69, 265-302.
17. Dittus, W.P.J. 1977. The social regulation of population density and age-sex distribution in toque monkey. Behaviour 63(2), 281-322.
The macaques constitute a genus (Macaca) of gregarious Old World monkeys of the subfamily Cercopithecinae. The 23 species of macaques inhabit ranges throughout Asia, North Africa, and Europe. Macaques are principally frugivorous, although their diet also includes seeds, leaves, flowers, and tree bark. Some species such as the long tailed macaque will supplement their diets with small amounts of meat from shellfish, insects, and small mammals. On average, southern pig-tailed macaques in Malaysia eat about 70 large rats each per year. All macaque social groups are matriarchal, arranged around dominant females.
The crab-eating macaque, also known as the long-tailed macaque and referred to as the cynomolgus monkey in laboratories, is a cercopithecine primate native to Southeast Asia. A species of macaque, the crab-eating macaque has a long history alongside humans. The species has been alternately seen as an agricultural pest, a sacred animal, and, more recently, the subject of medical experiments.
The rhesus macaque, colloquially rhesus monkey, is a species of Old World monkey. There are between six and nine recognised subspecies that are split between two groups, the Chinese-derived and the Indian-derived. Generally brown or grey in colour, it is 47–53 cm (19–21 in) in length with a 20.7–22.9 cm (8.1–9.0 in) tail and weighs 5.3–7.7 kg (12–17 lb). It is native to South, Central, and Southeast Asia and has the widest geographic range of all non-human primates, occupying a great diversity of altitudes and a great variety of habitats, from grasslands to arid and forested areas, but also close to human settlements. Feral colonies are found in the United States, thought to be either released by humans or escapees after hurricanes destroyed zoo and wildlife park facilities.
The Barbary macaque, also known as Barbary ape, is a macaque species native to the Atlas Mountains of Algeria, Libya, Tunisia and Morocco, along with a small introduced population in Gibraltar. It is the type species of the genus Macaca. The species 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 both sexes and all ages contribute in alloparental care of young.
The Japanese macaque, also known as the snow monkey, is a terrestrial Old World monkey species that is native to Japan. Colloquially, they are referred to as "snow monkeys" because some live in areas where snow covers the ground for months each year – no other non-human primate lives farther north, nor in a colder climate. Individuals have brownish grey fur, pinkish-red faces, and short tails. Two subspecies are known.
Gray langurs, also called are Old World monkeys native to the Indian subcontinent constituting the genus Semnopithecus. Traditionally only one species Semnopithecus entellus was recognized, but since about 2001, additional species have been recognized. The taxonomy has been in flux, but currently eight species are recognized.
The purple-faced langur, also known as the purple-faced leaf monkey, is a species of Old World monkey that is endemic to Sri Lanka. The animal is a long-tailed arboreal species, identified by a mostly brown appearance, dark face and a very shy nature. The species was once highly prevalent, found in suburban Colombo and the "wet zone" villages, but rapid urbanization has led to a significant decrease in the population level of the monkeys. It had traditionally been classified within the lutung genus Trachypithecus but was moved to the genus Semnopithecus based on DNA evidence indicating that is it more closely related to the gray langurs.
The Moor macaque is a macaque monkey with brown/black body fur with a pale rump patch and pink bare skin on the rump. It has ischial callosities, which are oval-shaped. It is about 50–58.5 cm long, and eats figs, bamboo seeds, buds, sprouts, invertebrates and cereals in tropical rainforests. It is sometimes called "dog-ape" because of its dog-like muzzle, although it is no more closely related to apes than any other Old World monkey is. It is endemic to the island of Sulawesi in Indonesia, which is an important biodiversity hotspot.
The lion-tailed macaque, also known as the wanderoo, is an Old World monkey endemic to the Western Ghats of South India.
The Arunachal macaque is a macaque native to Eastern Himalayas of Bhutan, China and India. It is listed as Endangered on the IUCN Red List.
Social grooming is a behavior in which social animals, including humans, clean or maintain one another's body or appearance. A related term, allogrooming, indicates social grooming between members of the same species. Grooming is a major social activity, and a means by which animals who live in close proximity may bond and reinforce social structures, family links, and build companionships. Social grooming is also used as a means of conflict resolution, maternal behavior and reconciliation in some species. Mutual grooming typically describes the act of grooming between two individuals, often as a part of social grooming, pair bonding, or a precoital activity.
The toque macaque is a reddish-brown-coloured Old World monkey endemic to Sri Lanka, where it is known as the rilewa or rilawa, . Its name refers to the whorl of hair at the crown of the head, reminiscent of a brimless toque cap.
Linda Marie Fedigan, is a professor and Canada Research Chair in Primatology and Bioanthropology at the University of Calgary, Alberta. In addition, Fedigan is also the Executive Editor of the American Journal of Primatology and a fellow of the Royal Society of Canada. Prior to accepting her current position, Dr. Fedigan was a professor at the University of Alberta, teaching anthropology from 1974 until 2001. She is internationally recognized for over 30 years of contribution to the study of primate life history, reproduction, socioecology and conservation and is considered a major authority on the life history and reproductive patterns of female primates.
The tufted gray langur, also known as Madras gray langur, and Coromandel sacred langur, is an Old World monkey, one of the species of langurs. This, like other gray langurs, is mainly a leaf-eating monkey. It is found in southeast India and Sri Lanka. It is one of three Semnopithecus species named after characters from The Iliad, S. hector and S. ajax being the others. In Sinhala it is known as හැලි වදුරා.
Sexual swelling, Sexual skin,or Anogenital tumescence refers to localized engorgement of the anus and genital region of some female primates that vary in size over the course of the menstrual cycle. Thought to be an honest signal of fertility, male primates are attracted to these swellings; preferring, and competing for, females with the largest swellings.
In biology, paternal care is parental investment provided by a male to his own offspring. It is a complex social behaviour in vertebrates associated with animal mating systems, life history traits, and ecology. Paternal care may be provided in concert with the mother or, more rarely, by the male alone.
Non-reproductive sexual behavior consists of sexual activities animals participate in that do not lead to the reproduction of the species. Although procreation continues to be the primary explanation for sexual behavior in animals, recent observations on animal behavior have given alternative reasons for the engagement in sexual activities by animals. Animals have been observed to engage in sex for social interaction bonding, exchange for significant materials, affection, mentorship pairings, sexual enjoyment, or as demonstration of social rank. Observed non-procreative sexual activities include non-copulatory mounting, oral sex, genital stimulation, anal stimulation, interspecies mating, and acts of affection, although it is doubted that they have done this since the beginning of their existence. There have also been observations of sex with cub participants, same-sex sexual interaction, as well as sex with dead animals.
Monkey Kingdom is a 2015 American nature documentary film directed and produced by Mark Linfield and Alastair Fothergill and narrated by Tina Fey. The documentary is about a family of monkeys living in ancient ruins founded in the jungles of Polonnaruwa in Sri Lanka. The film was released by Disneynature on April 17, 2015, the eighth nature documentary released under that label.
Infanticide in non-human primates occurs when an individual kills its own or another individual's dependent young. Five hypotheses have been proposed to explain infanticide in non-human primates: exploitation, resource competition, parental manipulation, sexual selection, and social pathology.
Lynne A. Isbell is an American ethologist and primatologist, professor of anthropology at the University of California, Davis.