Wolfgang P J Dittus

Smithsonian Institution · Conservation Ecology Center

Many investigators of human-monkey competition (HMC) in Sri Lanka have revealed some common threads. Except at temple and protected sites, all monkeys were considered as household or agricultural pests wherever they shared space with humans. This included the widely distributed toque macaque (Macaca sinica), the grey langur (Semnopithecus priam the...

When monkeys, such as the toque macaques (Macaca sinica) of Sri Lanka, seek food on the ground near human habitation, they may use electrical posts to escape aggression from conspecifics, dogs, or humans. Shields mounted on electrical posts prevented monkeys from reaching the electrical wires, thereby averting their electrocution: the frequency of...

Sri Lanka is a biodiversity hotspot with high human density that contributes to increasing human-monkey conflict (HMC). In 50 years of primate studies there, the development of HMC has been documented, and many workshops and interventions organized to ameliorate HMC. These activities prompted the present survey. In the extensive lowland dry zone of...

All mammals originated on the supercontinent of Pangaea in the Mesozoic era during the “Age of Reptiles.” However, the crown ancestors of contemporary mammals did not flourish until major environmental and biotic changes had occurred. An asteroid collided with earth at the end of the Cretaceous Period (the K-Pg boundary event) wiping out non-flying...

The vitamin D receptor is found on most cells, including active immune cells, implying that vitamin D has important biological functions beyond calcium metabolism and bone health. Although captive primates should be given a dietary source of vitamin D, under free-living conditions vitamin D is not a required nutrient, but rather is produced in skin...

Skinfold thickness (SFT) has been used often in non-human primates and humans as a proxy to estimate fatness (% body fat). We intended to validate the relation between SFT (in recently deceased specimens) and the mass of adipose tissue as determined from dissection of fresh carcasses of wild toque macaques (Macaca sinica). In adult male and female...

Subspecies embody the evolution of different phenotypes as adaptations to local environmental differences in keeping the concept of the Evolutionary Significant Unit (ESU). Sri Lankan mammals, being mostly of Indian-Indochinese origins, were honed, in part, by the events following the separation of Sri Lanka from Gondwana in the late Miocene. The e...

There is a paucity of information on body composition and fat patterning in wild nonhuman primates. Dissected adipose tissue from wild toque macaques (Macaca sinica) (WTM), feeding on a natural diet, accounted for 2.1% of body weight. This was far less than fatness reported for nonhuman primates raised in captivity or for contemporary humans. In WT...

Human and great ape milks contain a diverse array of milk oligosaccharides, but little is known about the milk oligosaccharides of other primates, and how they differ among taxa. Neutral and acidic oligosaccharides were isolated from the milk of three species of Old World or catarrhine monkeys (Cercopithecidae: rhesus macaque (Macaca mulatta), toqu...

Fatty acids in milk reflect the interplay between species-specific physiological mechanisms and maternal diet. Anthropoid primates (apes, Old and New World monkeys) vary in patterns of growth and development and dietary strategies. Milk fatty acid profiles also are predicted to vary widely. This study investigates milk fatty acid composition of fiv...

Infections from Cryptosporidium parvum are of interest not only to public health, but also to wildlife conservation, particularly when humans and livestock encroach on nature and thereby increase the risk of cross-species transmissions. To clarify this risk, we used polymerase chain reaction to examine the hypervariable region of the C. parvum 18S...

Cryptosporidiosis is a rapidly emerging disease in the tropics. This is the first report of Cryptosporidium and other protozoan infections (Entamoeba spp., Iodamoeba, Chilomastix, and Balantidium spp.) in wild primates that inhabit the natural forest of Sri Lanka. It is unclear if non-human primates serve as a reservoir for these parasites under ce...

From a natural population that inhabits the dry evergreen forest at Polonnaruwa, serum samples of 170 toque macaques were examined for antibodies to Toxoplasma gondii by the modified agglutination test. Of these, 21 (12%) were found with titers of 1:16 in 9, 1:32 in 9, 1:256 in 1, 1:1,024 in 1, and 1:4,096 in 1. There was no evidence of maternal tr...

Hematological studies were conducted in three wild groups of toque macaques (Macaca sinica) inhabiting the Polonnaruwa Sanctuary in northeastern Sri Lanka. The macaques were temporarily trapped and anesthetized, and femoral blood was drawn from 35 males and 37 females (age range: 0.33-24.5 yr). Statistically significant (P<0.05) differences were ob...

Dengue is one of the most rapidly emerging diseases in the tropics. Humans are the principal reservoir of dengue viruses. It is unclear if nonhuman primates also serve as a reservoir of human dengue viruses under certain conditions. In this study, a cross-sectional serologic survey was carried out to characterize the pattern of transmission of a re...

Mammalian life histories suggest that maternal body condition and social dominance (a measure of resource-holding potential) influence the physical and social development of offspring, and thereby their reproductive success. Predictably, a mother should produce that sex of offspring which contributes most to her fitness (as measured by the number o...

Genetic variation at four microsatellite loci in conjunction with that at a highly variable allozyme locus was used to analyse paternity over a 12-year period in 13 social groups of toque macaques Macaca sinica inhabiting a natural forest in Polonnaruwa, Sri Lanka. Paternity exclusion analysis revealed that the set of offspring produced by a female...

The mitochondrial genome has been an important molecular marker for phylogeographic studies. Because of its maternal mode of inheritance and rapid rate of evolution, mtDNA analysis is useful in obtaining information on the genetic structure and biogeographical history of a population. Hoelzer et. al. (Molecular Ecology, In Press) recently analyze...

Surveys of mitochondrial DNA (mtDNA) variation in macaque monkeys have revealed extremely high levels of intraspecific divergence among haplotypes. One consistent pattern that has emerged from these studies is that divergent haplotypes are geographically segregated so that sampling a few matrilines from a given region shows them to be identical, or...

Paternity in toque macaques, Macaca sinica, cannot be reliably determined based on behavioral data due to their multi-male group structure and promiscuous mating patterns. In such species, paternity discrimination requires the use of novel genetic markers. In this study we have used two classes of genetic markers to examine male mating patterns in...

A seroepidemiological study of arboviruses infecting 115 wild toque macaques (Macaca sinica) at Polonnaruwa, Sri Lanka showed a high prevalence of antibodies to dengue and Lumbo viruses. There was low seroprevalence of Chandipura (2/115) and Batai (1/115) virus antibodies, but no seropositivity to Chikungunya or Sindbis. There was no serological ev...

Growth studies of non-human primates in natural populations are rare due to difficulties in obtaining measurements on animals of known age. We report a cross-sectional analysis of growth in the natural population of toque macaques (Macaca sinica) from Polonnaruwa, Sri Lanka, including the timing of growth and physical maturation and the development...

The heritability of quantitative traits, or the proportion of phenotypic variation due to additive genetic or heritable effects, plays an important role in determining the evolutionary response to natural selection. Most quantitative genetic studies are performed in the laboratory, due to difficulty in obtaining genealogical data in natural populat...

Toque macaques (Macaca sinica),inhabiting natural forest at Polonnaruwa, Sri Lanka, are frequently injured in fights with conspecifics. The behavior of known individuals when they were injured was compared to that after they had recovered their health. Thus, injured animals rested and alloand autogroomed more, but they foraged less and initiated fe...

Helminth parasites were identified in a natural population of primates at Polonnaruwa, Sri Lanka. Five fatally wounded or recently deceased toque macaques (Macaca sinica) and three langurs (Presbytis senex andP. entellus) were autopsied. The following nematodes were found:Oesophagostomum aculeatum (Chabertiidae),Streptopharagus pigmentata (Spirocer...

Helminth parasites were identified in a natural population of primates at Polonnaruwa, Sri Lanka. Five fatally wounded or recently deceased toque macaques (Macaca sinica) and three langurs (Presbytis senex and P. entellus) were autopsied. The following nematodes were found: Oesophagostomum aculeatum (Chabertiidae), Streptopharagus pigmentata (Spiro...

Most toque macaques give birth to their infants during the night when resting arboreally. Here we report on a birth that occurred in daytime (at 0916 hr) and on the ground. The mother was 7.6 years old; the birth was her second. Prepartum behaviors included lordosis, arching of the back, stretching, squatting, rolling on the ground, and anogenital...

At Polonnaruwa, Sri Lanka, four out of 29, groups of toque macaques, Macaca sinica, divided in a period of 16 years. Temporary peripheral subgroups of varying sizes and compositions preceded fission by 9–40 months. Fission crystallized within a month through an increase and stabilization of subgroup membership and permanent division. All members in...

The manner in which individuals in social groups space themselves in relation to each other and to other groups partly reflects how they might share limiting resources with one another, select their mates, care for their young, and protect one another against predators or resource competitors. Within most primate societies, not all members are equa...

1. Two independent groups of toque macaques (Macaca sinica) fused into one larger cohesive group. The groups were part of a population of 18 to 22 groups that inhabit natural forest at Polonnaruwa, Sri Lanka, and that had been observed more or less continuously from 1968 to 1985. 2. The group fusion generally supports WRANGHAM'S (1980) model of the...

A group of toque macaques took-over the home range of one of its subordinate neighboring groups and fused with it to form a larger cohesive group. In the 7 years before the take-over, the dominant group had consistently won all contests at common feeding sites, yet the fitnesses of the females of these two groups did not differ significantly (Fig....

A cyclone in November 1978 caused extensive damage to a site of natural dry evergreen forest in Sri Lanka. The cyclone destroyed more than 50 percent of the woody vegetation that had produced most of the food for two species of leaf-eating monkeys or langurs. Apparently, this caused an imbalance between these langur populations and their natural fo...

Damage included defoliation, breakage of twigs, branches and trunks, tree falls and post-cyclone tree mortality. Extrapolations from meteorological data indicate that 33-44% of the range of dry evergreen forest may be subject to cyclone damage per century. The species composition of dry evergreen forest on a local and wider geographical scale typic...

Upon the rare occasions that wild toque macaques (Macaca sinica) discover a large quantity of food in their natural forest environment they give distinctive calls. The durations of feeding bouts and the rates of feeding are significantly greater at sites where food calls are given than at sites of the same food types where no foods call are given....

In einer vorher veröffentlichten Arbeit (DITTUS, 1977a) wurden die Beziehungen zwischen Daten betreffend Verhalten, Ökologie und Demographie einer Population von etwa 450 Hutaffen, Macaca sinica, untersucht. Diese Daten weisen darauf hin, dass die Grössen von Trupps (und daher der Population) dem Nahrungsangebot angepasst sind, und durch Ausgleiche...

Semi-evergreen forests cover the dry zone plains of Sri Lanka and constitute four-fifths of the island's vegetation. In a sample area of 3 km2, in the Polonnaruwa Sanctuary, 63 tree species were found; 46 were characteristic of other dry zone forests, and 17 occurred only under special edaphic and biotic conditions. As in other dry zone forests, Dr...

Thesis (Ph. D.)--University of Maryland, 1974. Includes bibliographical references. Photocopy. s

1.1. This paper attempts to elucidate the process of song development in the cardinal, a species which has several song patterns per individual which are essentially similar among neighbours but often different between different localities.2.2. Cardinals taken from nests in Ontario at ages 5 to 8 days were exposed to a maximum age of 15 weeks to re...