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Objectives: Raising offspring imposes energetic costs, especially for female mammals. Consequently, seasons favoring high energy intake and sustained positive energy balance often result in a conception peak. Factors that may weaken this coordinated effect include premature offspring loss and adolescent subfertility. Furthermore, seasonal ingestion of phytochemicals may facilitate conception peaks. We examined these factors and potential benefits of a conception peak (infant survival and interbirth interval) in Phayre's leaf monkeys (Trachypithecus phayrei crepusculus). Materials and Methods: Data were collected at Phu Khieo Wildlife Sanctuary, Thailand (78 conceptions). We estimated periods of high energy intake based on fruit and young leaf feeding and via monthly energy intake rates. Phytochemical intake was based on fecal progestin. We examined seasonality (circular statistics and cox proportional hazard models) and compared consequences of timing (infant survival and interbirth intervals, t‐test, and Fisher exact test). Results: Conceptions occurred in all months but peaked from May to August. This peak coincided with high fecal progestin rather than presumed positive energy balance. Primipara conceived significantly later than multipara. Neither infant survival nor interbirth intervals were related to the timing of conception. Discussion: Periods of high energy intake may not exist and would not explain the conception peak in this population. However, the presumed high intake of phytochemicals was tightly linked to the conception peak. Timing conceptions to the peak season did not provide benefits, suggesting that the clustering of conceptions may be a mere by‐product of phytochemical intake. To confirm this conclusion, seasonal changes in phytochemical intake and hormone levels need to be studied more directly. [ABSTRACT FROM AUTHOR]

The prevalence of exclusive breastfeeding in Thailand is the lowest in all of Asia. This study aimed to examine if breastfeeding-friendly policies in a factory influenced breastfeeding behaviors among Thai working mothers. Descriptive data was collected from 216 eligible factory-working mothers of children aged 6-12 months. Data collected included the Demographic Characteristic Questionnaire and the Breastfeeding in the Workplace Survey. Questions included: awareness of factory breastfeeding-friendly policies, breastfeeding behaviors, pumping in the workplace, social support for breastfeeding behaviors during work. Data were analyzed by descriptive statistics. The majority of mothers (93.1%) intended to breastfeed with 93.1% also reporting shift work. Most of them rated the factory's support as excellent and very good. The rate of exclusive breastfeeding declined from 76.9% at one month to 46.3% at three months, then sharply dropped to 16.2% at four months and 7.4% at six months. Reasons for breastfeeding discontinuation included: maternal report of insufficient milk (36%), infant sent to live with grandmother in other areas (31%), and returning to work (12%). Breastfeeding-friendly policies in factories could improve breastfeeding rates during first three months. However, working mothers may need continued information and resources such as why continued breastfeeding is important, how to maintain sufficient milk supply, on-site child care facilities, and managing family life. Occupational health nurses could provide onsite breastfeeding training and/or intervention programs to improve exclusivity and duration of breastfeeding, instructions on use of breast pumps, and lactation support programs in the workplace, especially for women who work shifts. [ABSTRACT FROM AUTHOR]

The marbled cat (Pardofelis marmorata) is arguably one of the least known Southeast Asian felids. Based mainly on indirect evidence, a nocturnal and predominantly arboreal lifestyle has been assumed while little is known about its diet. Here we report how a marbled cat injured a juvenile male Phayre's leaf monkey (Trachypithecus phayrei crepusculus; 33 months old) at the neck and shoulder within the Phu Khieo Wildlife Sanctuary, Thailand. The event suggests that this small cat may prey on individuals with a body mass exceeding its own and confirms that it can be active during early morning hours indicating a crepuscular-diurnal activity. There are also first indications that individual differences in monkey behaviour such as preferred feeding height, could influence predation risk. [ABSTRACT FROM AUTHOR]

ABSTRACT Although it is known that forest loss and degradation negatively impact most forest-dwelling primates, such relationships are difficult to quantify because many primates are difficult to survey over large areas. Furthermore, recovery times are also difficult to assess due to a lack of long-term data. Here, we determined how forest characteristics and habitat disturbance correlate with the abundance of pileated gibbons, Hylobates pileatus. We studied a population in Khao Ang Rue Nai Wildlife Sanctuary in southeastern Thailand, assessed its density using an auditory method combined with distance sampling at 24 randomly placed sample sites. In addition, we determined how simple forest structural characteristics and habitat disturbance correlate with the gibbon abundance. Average gibbon density per site was 1.02 ± 0.16 (SE) groups/km2 (range 0-2.74). Bivariate analyses indicated that densities depended on food tree biomass, level of disturbance, evergreen forest cover, time since protection, and distance to the sanctuary boundary. Multiple regression analysis suggested evergreen forest cover and distance to boundary were the most influential factors. Because evergreen forest cover, time since protection, and habitat disturbance are correlated, these results suggest a direct dependence of gibbon densities on mature, undisturbed evergreen forest. While gibbons can persist in disturbed areas if the forest is protected, it appears that recovery to previous densities may take decades. We suggest that this is due to the slow pace of forest regeneration and/or poor recovery potential of gibbons. [ABSTRACT FROM AUTHOR]

Selection and use patterns of sleeping sites in nonhuman primates are suggested to have multiple functions, such as predation avoidance, but they might be further affected by range defense as well as foraging constraints or other factors. Here, we investigate sleeping tree selection by the male and female members of one group of pileated gibbons (Hylobates pileatus) at Khao Ang Rue Nai Wildlife Sanctuary, Thailand. Data were collected on 113 nights, between September 2006 and January 2009, yielding data on 201 sleeping tree choices (107 by the female and 94 by the male) and on the characteristics of 71 individual sleeping trees. Each sleeping tree and all trees ≥40 cm diameter at breast height (DBH) in the home range were assessed (height, DBH, canopy structure, liana load) and mapped using a GPS. The gibbons preferentially selected tall (mean=38.5 m), emergent trees without lianas. The majority of the sleeping trees (53.5%) were used only once and consecutive reuse was rare (9.5%). Sleeping trees were closer to the last feeding tree of the evening than to the first feeding tree in the morning, and sleeping trees were located in the overlap areas with neighbors less often than expected based on time spent in these areas. These results suggest avoidance of predators as the main factor influencing sleeping tree selection in pileated gibbons. However, other non-mutually exclusive factors may be involved as well. Am. J. Primatol. 72:617–625, 2010. © 2010 Wiley-Liss, Inc. [ABSTRACT FROM AUTHOR]

Socioecological theory suggests a link between the strength of competition for food/safety, rates of agonism, structure of dominance hierarchies, and dispersal among group-living females. This study presents preliminary data on agonistic behavior and dominance relationships for female Phayre's leaf monkeys (Trachypithecus phayrei), a species in which females routinely disperse. Behavioral observations were conducted on two groups (four adult females, and five adult females plus two juvenile females, respectively) at Phu Khieo Wildlife Sanctuary, northeast Thailand. Rates of agonistic behavior were analyzed from focal continuous recordings, while dominance hierarchies were constructed from all agonistic behaviors (focal and ad libitum sampling). Overall, female-female agonistic behaviors (aggression, submission, and displacements) occurred at a rate of <0.25 interactions per hour. Agonistic interactions involving food occurred more frequently than expected based on feeding time. Females in both groups exhibited linear dominance hierarchies with some reversals, and possibly an age-inversed hierarchical structure in the larger group. The results fit well with previous results for colobine monkeys regarding frequency of interactions, displacements predominating agonistic behavior, and the possibility of an age-inversed hierarchy. The results contradict the suggested link between linearity of hierarchies and female philopatry. Future studies should consider the notion that female dispersal may coexist with linear dominance hierarchies. [ABSTRACT FROM AUTHOR]

Objectives: Allomaternal care (AMC) is suggested to be energetically beneficial to mothers and costly to allomothers. However, among primates, AMC is a heterogeneous phenomenon and its implications are less clear especially in female dispersal species. Here, we investigated infant care in a female dispersal species, Phayre's leaf monkeys (Trachypithecus phayrei crepusculus), to evaluate whether mothers were constrained by infant care and benefitted energetically from AMC, whether AMC was energetically costly for allomothers and how maternal experience was associated with AMC., Materials and Methods: Data were collected via instantaneous focal animal sampling between 2004 and 2005 for juvenile and adult females (N = 18) from two groups at the Phu Khieo Wildlife Sanctuary, Thailand (440 h). We used generalized linear mixed models to determine how infant care during the first month after birth affected the time mothers and allomothers spent feeding, socializing, resting, and locomoting and how AMC varied., Results: In the first month, infants spent 26% of their time with an allomother. We found no differences in mothers' overall activity before versus after birth, although mothers fed significantly more and rested less when without their infant. Allomothers fed and rested less when with an infant. AMC varied between 0.0% and 20.5%, with immature females being most active., Discussion: Mothers appear to benefit energetically from AMC such that their overall activity after birth remained unchanged. Costs and benefits for allomothers seem to be variable. Some very active immature females may be benefitting from learning-to-mother. The overall low cost of AMC may facilitate a reciprocal social network among unrelated females., (© 2024 The Author(s). American Journal of Biological Anthropology published by Wiley Periodicals LLC.)

Group living may entail local resource competition (LRC) which can be reduced if the birth sex ratio (BSR) is biased towards members of the dispersing sex who leave the group and no longer compete locally with kin. In primates, the predicted relationship between dispersal and BSR is generally supported although data for female dispersal species are rare and primarily available from captivity. Here, we present BSR data for Phayre's leaf monkeys ( Trachypithecus phayrei crepusculus ) at the Phu Khieo Wildlife Sanctuary, Thailand ( N = 104). In this population, nearly all natal females dispersed, while natal males stayed or formed new groups nearby. The slower reproductive rate in larger groups suggests that food can be a limiting resource. In accordance with LRC, significantly more females than males were born (BSR 0.404 males/all births) thus reducing future competition with kin. This bias was similar in 2-year-olds (no sex-differential mortality). It became stronger in adults, supporting our impression of particularly fierce competition among males. To better evaluate the importance of BSR, more studies should report sex ratios throughout the life span, and more data for female dispersal primates need to be collected, ideally for multiple groups of different sizes and for several years.