Home Range Size and Habitat use by Cat Ba Langurs (<Emphasis Type="Italic">Trachypithecus poliocephalus</Emphasis>) in a Disturbed and Fragmented Habitat

Primate home range size and habitat use are affected by resource availability, which may change seasonally. Limestone langurs (Trachypithecus genus), including the Critically Endangered Cat Ba langur (Trachypithecus poliocephalus), live on limestone karst hills with shrubby and discontinuous vegetation. This study explores home range size and habitat use in relation to substrate, vegetation coverage, and hill type for Cat Ba langurs living on Cat Ba Island. We predicted that home range size would be similar to that of other limestone langurs and that as resources vary seasonally and across habitat types, habitat use would vary with season and behavior, with foraging concentrated on slopes, where food is plentiful. We collected 180 days of observational data on two reproductive groups (N?=?7 and N?=?10–13), taking GPS fixes of the group whenever they moved farther than the typical group spread to determine home ranges, and 10-min instantaneous scans to assess habitat use. The two groups had home ranges of 22 ha and 50 ha (0.32 and 0.20–0.26 individuals/ha respectively). Ranges for both groups were smaller in the dry season than the wet season, although we could not assess seasonal variation statistically. The langurs spent most scans on rocks, in sparsely vegetated areas, and on exposed slopes and steep cliffs; however they foraged primarily on gradually inclined slopes, especially in the dry season. These results suggest that conservation efforts should focus on protecting nutritionally important valleys and exposed slopes to ensure year-long access to food resources. It may, however, be difficult to balance human and nonhuman primate habitat use.     

Factors Affecting the Ranging Behavior of White-headed Langurs (<Emphasis Type="Italic">Trachypithecus leucocephalus</Emphasis>)

Ranging behavior is an important aspect of animal behavior that researchers use to investigate ecological influences on individual behavior. We studied the influence of diet, water resources, and sleeping sites on the ranging behavior of 2 groups of white-headed langurs (Trachypithecus leucocephalus) in a limestone habitat at Fusui Nature Reserve, China, between August 2007 and July 2008. During the study period, the total home range sizes for the 2 focal groups were 23.8 ha and 33.8 ha, the mean daily path lengths were 491 m and 512 m, and leaves accounted for 83.4% and 91.0% of the diet, which are well within the range of variation reported for other Trachypithecus. One focal group traveled significantly longer distances in the rainy season months than in the dry season months. This variation may be related to the seasonal difference in food availability and diet. The langurs did not use their home ranges uniformly, and 50% of their activities occurred within 11% (group 1) and 20% (group 2) of their home ranges. The most heavily used quadrats in the home ranges were located near the most frequently used sleeping sites. Moreover, the core areas (>70% of location records) of both groups’ home ranges included ≥1 permanent water pool. The langurs ventured to these pools for drinking when surface water became scarce in the dry season. These results suggest that sleeping sites and water scarcity may be significant influences on the ranging behavior of white-headed langurs in limestone habitat.     

Habitat Quality and Activity Budgets of White-Headed Langurs in Fusui,China

Within a species, habitat quality may be a factor causing different activity budgets between populations. The habitat of white-headed langurs (Trachypithecus leucocephalus) has been seriously disturbed in Fusui Rare and Precious Animal Nature Reserve, China, where we carried out a study of their socioecology from September 1997 to September 1998. We collected data on langur activity budgets from the main population located in the central part of a group of limestone hills. We classified habitat quality into 4 grades according to the extent of human disturbance. We showed that the two main study groups of white-headed langurs spent on average 50% of time resting, 13% feeding, 18% moving (including foraging), 11% grooming, and 7% playing. Langur time budgets showed no significant seasonal change, but they differed among different sex-age classes. Infants and juveniles spent about 20.3% of time playing, whereas adults spent only 0.2% playing. The group in high quality habitat engaged less in feeding and more in playing than the group in low quality habitat did. Habitat quality influenced the playing time of young white-headed langurs and may be vital to their successful maturation.     

Long-Term Habitat Use by Mountain Gorillas (Gorilla gorilla beringei). 1. Consistency, Variation, and Home Range Size and Stability

Mountain gorillas are highly folivorous. Food is abundant and perennially available in much of their habitat. Still, limited research has shown that single gorilla groups heavily used areas where food biomass and quality were relatively high and where they met daily nutritional needs with relatively low foraging effort. Also, ecological factors influenced solitary males less than groups with females. Long-term data on habitat use by multiple mountain gorilla social units and more extensive data on variation in food distribution, presented here, confirm that food distribution influences areal occupation densities across groups and over time. These data also confirm the group/solitary male distinction and show that food distribution became more important for one male once he acquired females. Groups used 25 km ² , and inter-annual home range and core area overlap was often low. Annual home range and core area size varied considerably within groups and across years. It bore no simple relationship to group size and estimated group biomass. Core areas were biased samples of total home ranges and were relatively good foraging areas. One group abruptly shifted its home range in response to male mating competition. Home ranges of two others expanded from 1981 to 1987, though at a decreasing rate. Data on one such group, which varied considerably in size, are consistent with arguments that costs of scramble competition are low except in unusually large groups. Low site fidelity, low scramble costs, and high home range overlap should decrease the ecological costs of female transfer.     

What shapes intra‐specific variation in home range size? A case study of female roe deer

Spatial distribution in mammals, and thereby home range size, is influenced by many different factors including body size, sex, age, reproductive status, season, availability of forage, availability of water, fragmentation of landscape, trophic level and intra- and inter-specific competition. Using linear mixed models, we looked for factors shaping the variation in size of spring-summer and winter home ranges for 51 radio-collared adult female roe deer at Trois Fontaines forest, Champagne–Ardenne, France (1996–2005). Home range size of females was larger in winter than in spring–summer, decreased with age, and decreased with increasing quality. Females in low quality areas adjusted the size of their home range to include more patches of habitat so that all female deer obtained similar amounts of food resources (total biomass of 6.73±2.34 tons (mean±SE) for each home range). Such adjustments of home range size in response to patchiness of resources led to marked between-female variation in home range size. Our results demonstrate that roe deer females have different tactics of habitat use according to spatial variations in habitat quality so that females get similar food resources in highly productive environments such as the Trois Fontaines forest.     

Group living, breeding behaviour and territoriality in the Subdesert Mesite Monias benschi

In 1997–2000 we studied a population of Subdesert Mesites Monias benschi consisting of 35–68 adults comprising 32 groups of two to nine birds (modal group size of four). The study population was significantly male-biased in 1999 but not in 1997 or 1998. Overall, both sexes were philopatric, but when dispersal (or eviction) occurred, it appeared to be female-biased. Over 40% of groups contained more than two adult males, whilst < 15% contained more than two adult females. Whilst there was no evidence of behavioural dominance by females, intrasexual aggression within groups was observed only amongst females. In contrast to other birds occupying the same habitat, breeding in mesites was not tied to rainfall, and occurred throughout the year. Each breeding unit constructed several nests every year, only one of which was used. All adult males and at least one adult female co-operated to raise one or two clutches of one or two eggs per year. Males and females contributed equally to incubation. Chick production and chick survival were not related to group size or territory size. Groups defended large, permanent, and multipurpose territories and all group members contributed to territory defence. Territory size was positively correlated with the number of males in groups, but not with overall group size. Territories were tightly packed with very few areas unoccupied. Transect surveys conducted throughout the narrow geographical range of this species revealed its presence in a range of semi-arid habitat types. Small groups were more likely to be detected in intact, high-stature forest, whilst large groups were more likely to be detected in low-stature forest containing numerous spiny, xerophytic trees Didierea madagascariensis .     

Female dispersal,social organization,and infanticide in langurs: Are they linked to human disturbance?

Female dispersal in gregarious animals can involve the desertion of a site, desertion of a social group, or both. Group desertion may be related to inbreeding avoidance. Group fidelity may result from cooperation among females in a group. Site fidelity will be more likely when food can be monopolized and when the population density is close to habitat saturation. The degree of habitat saturation was approximated with a measure of human disturbance. The influence of these various factors on the incidence of female dispersal was investigated for langur populations using data from the literature. The results suggest that female dispersal in langurs involved site desertion, not group desertion. The incidence of female dispersal may affect the social organization of langurs. I propose that when females do not disperse, male takeovers prevail, whereas in populations where female dispersal regularly occurs bisexual groups are disbanded or new groups are formed, a process I call female split-merger. Male takeover is thought to occur when site fidelity is high, female split-merger when site fidelity is low. These processes were indeed found to occur in these circumstances. The dispersal of females might prevent infanticide, whereas male takeover might promote it. Indeed, in studies with male takeover, more infants fell victim to infanticide than in studies with female split-merger. Therefore, female dispersal in langurs is an effective female counterstrategy to infanticide. The factor that had the most profound effect on female dispersal, social organization, and infanticide was habitat saturation. Habitat saturation was measured as the degree of human disturbance, and its influence on the behavior of langurs is probably of relatively recent date. This may lead to an evolutionary transient situation and may explain the discrepancy between current socioecological theories and the behavior of langurs in populations lacking female dispersal. Am. J. Primatol. 44:235–254, 1998. © 1998 Wiley-Liss, Inc.     

Food Choice of White-Headed Langurs in Fusui,China

We studied the feeding ecology of white-headed langurs (Trachypithecus leucocephalus) from September 1997 to September 1998 in Fusui Rare and Precious Animal Reserve, SW Guangxi, China. We collected data in the central part of a group of limestone hills where the main population pool of langurs was located. The langurs fed on 50 plant species (belonging to 42 genera from 28 families) out of 164 species in the habitat (belonging to 112 genera from 48 families). Most of the food plant species were not common in the habitat. There are 16 important food species, including 6 key species. White-headed langurs were extremely folivorous, feeding mainly on young leaves (75% of total feeding records) of a broad range of less common plant species, which were in less disturbed areas. Thus, langur groups in high quality habitat had greater access to preferred foods, and the future of langurs in the Reserve may depend on immediate cessation of tree felling.     

Social organization of white‐headed langurs (Trachypithecus leucocephalus) in the Nongguan Karst Hills,Guangxi, China

The number of males per group is the most variable aspect of primate social organization and is often related to the monopolizability of females, which is mainly determined by the number of females per group and their reproductive synchrony. Colobines show both inter‐specific and intra‐specific variations in the number of males per group. Compared with other colobine species, little is known about the social organization of white‐headed langur (Trachypithecus leucocephalus), despite its endangered status and unusual limestone habitat. As a part of a long‐term study of the white‐headed langurs in the Nongguan Karst Hills, Guangxi, China, we quantitatively investigated their social organization by analyzing census data from 1998 to 2003. The population censuses revealed that the predominant social organization of bisexual groups was the one‐male group, similar to a previous report on this species and many other Asian colobines. In such groups, one adult male associated with 5.1 adult females, 0.1 sub‐adult males, 2.6 juveniles and 2.9 infants on average, with a mean group size of 11.7 individuals. In addition, three multi‐male groups were recorded, consisting of 2–3 adult males, 1–5 adult females, 0–2 sub‐adult males, 0–7 juveniles and 0–2 infants. They did not contain more adult females than the one‐male groups and were unstable in group membership. The langurs outside bisexual groups were organized into small nonreproductive groups or lived as solitaries. The nonreproductive groups averaged 1.3 adult males, 1.3 sub‐adult males and 2.6 juveniles. Juvenile females were present in such groups on 52.4% of all occasions. As predicted by the monopolization model, the prevalence of the one‐male pattern in this species may mainly be attributed to the small number of females in the group. The possible reasons for the occurrence of multi‐male groups and the presence of juvenile females in nonreproductive groups are also discussed. Am. J. Primatol. 71:206–213, 2009. © 2008 Wiley‐Liss, Inc.     

Sex Allocation in a Colobine Monkey

In polygynous, sexual dimorphic species with higher variance in male reproductive success compared with females, females are expected to invest more heavily in sons than daughters within the constraints imposed by their physical condition (Science 1973; 179:90). Mothers in good condition, usually those of high rank, should produce more sons than females in poor condition or of low rank. We investigated sex allocation and sex‐biased maternal investment in a population of wild Hanuman langurs using rank and group size as approximations of female physical condition. Our results show that reproductive costs of sons were higher with both significantly longer interbirth intervals following male births and longer lactational periods for sons. Not in all groups did analyses of rank‐dependent sex allocation reveal the expected pattern of high‐ranking mothers producing more sons. However, sex ratio was significantly influenced by group size, with females from larger groups, i.e., in worse physical condition, producing a daughter‐biased sex ratio. In fact, only females of population‐wide superior physical condition can be expected to produce sons, because in Hanuman langurs males disperse and compete population‐wide. Thus, our results support the Trivers–Willard model and may explain the mixed evidence accruing from studies of single groups. We present a graphical model of how group size and dominance‐related differences in energy gain may influence sex allocation under different competitive regimes relative to overall resource availability. Tests of adaptive sex allocation models should consider whether reproductive competition of the preferred sex takes place primarily within a group or within the population.     

Combining information from range use and habitat selection: sex-specific spatial responses to habitat fragmentation in tawny owls Strix aluco

How individuals respond to habitat heterogeneity is usually measured as variation in range size and by ranking the relative importance of habitat types (habitat selection). The combined effect of how individuals incorporate different habitat types in their home ranges and allocate their time budget between them is rarely derived. Additionally, when home range size varies between individuals, habitat selection analyses might be flawed if foraging decisions are based on variation in absolute rather than proportional availability. We investigated the suitability of standard analytical approaches by measuring the spatial responses of tawny owls to habitat fragmentation. These owls inhabited woodland of various sizes, representing a fragmentation gradient from open farmland with small, isolated woodland patches, to continuous woodland within their home ranges. In 17 territories within open farmland, the available area covered by woodland increased with the square root of the area of open land embraced in the home range. The owls did not display functional response in habitat selection, but females selected woodland more strongly than males. Females utilised woodland 10 times more intensively in farmland than in continuous woods, whereas males utilised farmland woods 3.2 times more intensively. Moreover, females in farmland exploited woodland 3.2 times as intensively as males, apparently because of higher travel costs in open areas. Since the extensive variation in intensity of use as a function of total availability was not indicated from the analysis of habitat selection, we suggest that information about intensity of use be more widely used as a supplementary measure of habitat use patterns than appears to be the practice at present.     

Social organization of Galagos in Kenyan coastal forests: I. Galago zanzibaricus

The social organization of Galago zanzibaricus was studied for the first time and the study included data from two different sites in the coastal forests of Kenya. A combination of mark-recapture and radio-tracking techniques was used to investigate patterns of inter- and intrasexual home range overlap. Associations in sleeping groups indicated social ties between individuals. Patterns of range use were established by radio-tracking focal individuals. Adult males generally had nonoverlapping ranges, shared with one or two females and their offspring with which the male regularly slept. Young females remained longer in their natal ranges than males and reproduced within their natal ranges. Range size and distance traveled per night were similar between the sexes; both sexes probably defended territories. None of the other galago (bushbaby) species studied to date show the degree of close male-female association found in G. zanzibaricus. This study thus extends the variety of social organization documented in nocturnal prosimians.     

Status and distribution of golden langurs (Trachypithecus geei) in Assam, India

The distribution of golden langurs (Trachypithecus geei) is limited to a small area of western Assam in northeast India and Bhutan between the rivers Manas in the east, Sankosh in the west, and Brahmaputra in the south. It is one of the most seriously endangered primate species of India. A comparative analysis based on satellite images taken in 1988 and 1998 showed a 50% loss of original golden langur habitat. Data on population dynamics collected using line transect and total count methods are presented here. An average group size of 8.2 (range 4.0-22.0) individuals was recorded. A total of 1,064 individuals were counted living in 130 groups. The sex ratio was 1.9-2.5 adult females for each adult male. A low percentage of juveniles and infants suggests that the population is unstable. Most of the groups had only one adult male. Small group sizes, isolated distribution, proportionately few infants and juveniles, and degrading habitat are all causes of concern. Demographic trends indicate a decline in the golden langur population.     

Woodland fragmentation affects space use of Eurasian red squirrels

When habitats become fragmented, variation in patch size and quality are expected to impose changes on the spacing pattern and social organization of animal populations. General theory predicts different possible responses including shrinking home ranges (fission response), increasing range overlap (fusion) and incorporation of multiple patches in the home range (expansion response) as fragmentation increases. We studied space use and social organization in a metapopulation of red squirrels (Sciurus vulgaris) in 15 woodland fragments differing in size and tree species composition. Home ranges and core areas of males were larger than females, and fragmentation had different and complex effects on the spacing pattern of both sexes. In food-supplemented patches, high densities led to increased intra-sexual overlap. In linear-shaped patches, squirrels used smaller home ranges and core areas and had lower male–male and male–female overlap levels, independent of patch quality or size. Home range and core area size of males increased with patch size, and male core areas overlapped extensively those of other males and females. Hence males seemed to show a fission response only in some patches. In contrast, home range and core area size of females was not related with patch size, but decreased with habitat quality, supporting predictions of a fusion response and intra-sexual defense of food-based core areas. Hence, where patch size and shape strongly affected space use of male red squirrels, social organization of females was only affected in small, food-supplemented patches, suggesting that the basic spatio-social organization of adult females is very resistant to fragmentation.     

Social group dynamics and composition of managed wild vicuñas (<Emphasis Type="Italic">Vicugna vicugna vicugna</Emphasis>) in Jujuy,Argentina

The vicuña is a high Andean wild camelid that lives year-long in groups. We analyzed the social organization of 98 marked vicuñas after capture and live shearing, focusing on group composition, spatial patterns, territoriality and habitat use. The social units analyzed were families, bachelor groups and solo animals. Location fixes of 54 males and 36 females were registered over a 2-year period, and home range was estimated. All females belonged to family groups, and 8–12 month yearlings changed their home ranges prior to first reproduction at 2 years. Female yearlings dispersed to a new family group, while male yearlings dispersed to a bachelor group. Solitary males appeared during the interval between leaving bachelor or family groups, and vice versa. Our study showed that vicuña polygyny was based on female grazing area requirements. Females that stayed with the same males were defined as loyal, and had a mean 18.9 ha home range. Females that changed both to a different family and male; and grazed over the same home range size, were considered disloyal. Family groups selected the habitat that had a low stratum and the highest coverage of palatable plants, while bachelors used their habitat randomly.     

Seasonality of group size,feeding, and breeding in wild red‐shanked douc langurs (Lao PDR)

In Asian colobines, small one‐male groups (OMG) seem to predominate alongside all‐male groups (AMG), while larger multimale groups (MMG) are rare, but are reported for Hanuman langurs and red‐shanked douc langurs. Recently, however, it has been speculated that the genus Pygathrix could have multilevel societies based on (1) a theoretical extension of the multilevel societies found in Rhinopithecus to all odd‐nosed colobines and (2) first data for black‐shanked douc langurs. This assumes bands composed of small OMG with a skewed adult sex ratio. Band size may vary with seasonal food availability resulting in smaller bands when feeding competition is increased. To investigate the social organization of red‐shanked douc langurs and potential seasonal influences, we observed 2 unhabituated groups at Hin Namno National Protected Area, Lao PDR from March 2007 to August 2008 for 803 hr. We recorded births and performed group counts and scan sampling of feeding behavior. Most births (79% of N = 15) occurred from June–September, indicating a 4‐month peak conception season from November to February. Group size averaged 24.5 individuals (range 17–45) with 2.45 adult males (range 1–4). Although the smaller group remained at a stable size (about 18 individuals), the larger group reduced from about 45 to 25 individuals during the 7‐months long lean season, when less than 50% of the feeding time was spent on fruits. This suggests feeding competition as a potential cause of seasonal variation in group size. With 1.9 females per male the skew in adult sex ratio was much lower compared with Rhinopithecus, indicating MMG rather than multilevel societies. However, data on the spacing and interaction patterns between recognized individuals need to be collected and analyzed before the social organization can be determined. Detailed ecological data are furthermore required to investigate the basis for the seasonal changes in group size found. Am. J. Primatol. 73:1134–1144, 2011. © 2011 Wiley Periodicals, Inc.     

Ranging Movements of Female Roe Deer: Do Home-loving Does Roam to Mate?

Bimonthly changes in home range size of seven mature roe deer Capreolus capreolus L. females were analysed over one year. Great stability of home range size and high site fidelity was common to all females, which remained bimonthly within areas of 6.1–20.8 ha. Two groups of females could be identified on the basis of bimonthly variations in their home range sizes: females with larger areas (LHR females), who decreased their ranges in the birth season only, and females with smaller home ranges (SHR females), who increased significantly their home ranges during the rut. The most likely explanation is that the areas inhabited by SHR females included high-quality food resources allowing survival even in small home ranges. In the rut, SHR females may have expanded their ranges to increase mating opportunities.     

Breeding variation in female kakapo (

We investigated why some mature females of New?Zealand?s critically endangered parrot, the kakapo (Strigops habroptilus), did not attempt to breed during the 2005 breeding season on Codfish Island. At a population level, the initiation of kakapo breeding appears to correspond with years of mast fruiting of rimu (Dacrydium cupressinum) trees, with the proportion of females that breed each season dependent on the quantity of rimu fruit available. This research investigates possible links between habitat quality within individual home ranges and the breeding status of adult females during 2005, when the abundance of available rimu fruit was low. We assessed the importance of both home range size and habitat characteristics in determining breeding attempts. Foraging home ranges were characterised using radio-tracking and triangulation techniques. The relative importance of habitat variables in optimal breeding habitat was assessed using ecological niche factor analysis. Our results show that female kakapo breeding in 2005 had, on average, home ranges twice the size of those females that did not breed that season and the ranges contained a significantly greater quantity of mature rimu forest. Multivariate analysis illustrates female kakapo were effectively partitioning available habitat, as breeders? foraging locations were positively correlated with high-abundance rimu forest with a tall canopy, described as optimal breeding habitat. In contrast non-breeders? locations were weakly correlated with short forest containing little or no mature rimu forest. To maximise reproductive output each breeding season, conservation managers need to ensure that all breeding-aged females occupy optimal breeding habitat on Codfish Island. Removal to other islands of kakapo not required in the breeding population may enable females to increase their home range size and occupy better breeding habitat.     

Troop size and human-modified habitat affect the ranging patterns of a chacma baboon population in the cape peninsula, South Africa

Differences in group size and habitat use are frequently used to explain the extensive variability in ranging patterns found across the primate order. However, with few exceptions, our understanding of primate ranging patterns stems from studies of single groups and both intra- and inter-specific meta-analyses. Studies with many groups and those that incorporate whole populations are rare but important for testing socioecological theory in primates. We quantify the ranging patterns of nine chacma baboon troops in a single population and use Spearman rank correlations and generalized linear mixed models to analyze the effects of troop size and human-modified habitat (a proxy for good quality habitat) on home range size, density (individuals/km(2) ), and daily path length. Intrapopulation variation in home range sizes (1.5-37.7 km(2) ), densities (1.3-12.1 baboons/km(2) ), and daily path lengths (1.80-6.61 km) was so vast that values were comparable to those of baboons inhabiting the climatic extremes of their current distribution. Both troop size and human-modified habitat had an effect on ranging patterns. Larger troops had larger home ranges and longer daily path lengths, while troops that spent more time in human-modified habitat had shorter daily path lengths. We found no effect of human-modified habitat on home range size or density. These results held when we controlled for the effects of both a single large outlier troop living exclusively in human-modified habitat and baboon monitors on our spatial variables. Our findings confirm the ability of baboons, as behaviorally adaptable dietary generalists, to not only survive but also to thrive in human-modified habitats with adjustments to their ranging patterns in accordance with current theory. Our findings also caution that studies focused on only a small sample of groups within a population of adaptable and generalist primate species may underestimate the variability in their respective localities.     

Variability in habitat, diet, and social structure of Hapalemur griseus in Ranomafana National Park, Madagascar

This study investigated the effects of habitat on the diet, population density, and social structure of a small-bodied folivore, Hapalemur griseus. Three groups of H. griseus were followed at two study sites (Tala and Vato) within Ranomafana National Park in southeastern Madagascar. These two sites differed in degree of habitat disturbance, forest composition, and forest structure, as determined by botanical plots (50 x 10 m) which were monitored twice monthly in the home ranges of three study groups (group T, n = 4; group V1, n = 4; group V2, n = 2). Tala has experienced more habitat disturbance compared to Vato, and this appeared to influence population density and group size. The H. griseus that inhabit Tala occur at much higher densities and in larger social groups than the H. griseus at Vato. These results may be attributable to: 1) a greater number of potential food sources, 2) a more dense resource base, and/or 3) higher-quality resources at Tala for this folivore. In general, dietary diversity for all groups was low, and groups exploited similar plant species. However, within this small range of food sources, each study group specialized in food sources found in the highest abundance within their home range. This resulted in dietary differences between groups within sites, as well as differences between sites. Introduced tree species such as Chinese guava (Psidium cattleyanum) may have greatly impacted the diet and social structure of those groups at Tala, whose home ranges included this food source. In contrast, Vato group 1 ingested more new and mature leaves of Ficus spp., and Vato group 2 primarily ate spider bamboo (Nastus elongatus). In conclusion, it seems that microhabitat differences, which may be related to habitat disturbance and/or other factors such as topography, influenced the food species ingested by H. griseus. Overall habitat quality, which is likely also affected by habitat disturbance, influenced general diet, population density, and group size.