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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]

To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.anbehav.2008.04.006 Byline: Amy Lu, Andreas Koenig, Carola Borries Abstract: Patterns of agonistic relationships among group-living mammalian females are suggested to reflect differences in feeding competition. Socioecological models predict that within-group contest (WGC) competition leads to despotic relationships that are linear, consistent, and stable, in which subordinate individuals use formal submission to acknowledge rank. Between-group contest (BGC) competition and risk of infanticide are predicted to add tolerance, as evidenced by frequent reconciliation, low-intensity aggression and counteraggression. We examined the predicted effects for formal submission and two criteria of tolerance for a group of Hanuman langurs (Semnopithecus entellus) in a population known to experience WGC and BGC as well as high rates of infanticide. Results were based on focal animal sampling of eight of 13 adult females (419h) and ad libitum sampling of all 13 females (711 contact hours) in the group Kailana I (Jodhpur, India). The behaviour 'presenting' (N =281) qualified as formal submission, adhering to most proposed criteria (e.g. linear, consistent, predictive of other agonistic relationships and hierarchies, 40.9% spontaneous). Thus, regarding formal submission, the predicted effects of WGC hold, and support the explanatory value of this aspect of socioecological models. In contrast, agonistic relationships were nontolerant, with frequent high-intensity aggression (48.9% of N =231) and almost no counteraggression ( Author Affiliation: (a) Interdepartmental Doctoral Program in Anthropological Sciences, Stony Brook University, U.S.A. (a ) Department of Anthropology, Stony Brook University, U.S.A. Article History: Received 10 October 2007; Revised 19 November 2007; Accepted 31 January 2008 Article Note: (miscellaneous) MS. number: A10878R

An investigation was carried out to assess what Hanuman langur males knew about female reproductive status, as indicated by changes in male behavior, such as rates of copulations, anogenital inspections, and consortships, in relation to different female receptive periods. Results showed that males were more interested in fertile than pregnant females, based on consortships males could distinguish fertile from nonfertile phases, as well as fertile, nonconceptional receptive periods from conceptional ones.

The occurrence of genital swellings in silvered langurs (Trachypithecus cristatus) is examined. The reasons for genital swellings have remained unclear, but the primates might exhibit three kinds of genital swellings, including exaggerated swellings that most closely indicate fertility and early pregnancy and much smaller swellings that indicate fertility or late gestation.

Preliminary data on agonistic behavior and dominance relationships for female Phayre's leaf monkeys, a species in which females routinely disperse is presented. Rates of agonistic behavior are analyzed from focal continuous recordings, while dominance hierarchies are constructed from all agonistic behaviors

The influence of sex, female reproductive status, dominance rank, and season on the duration of the active period of adult chimpanzees at Gombe National Park, Tanzania is investigated. The findings indicate that sexually nonreceptive females have shorter active periods compared to males, while receptive females have longer active periods than males.

Objectives: Geophagy has several hypothesized functions, among them (1) detoxification of plant secondary compounds, for example, tannins, (2) buffering stomach pH to alleviate acidosis caused by high sugar intake, and (3) supplementing the diet with mineral nutrients. We tested these hypotheses in Nepal gray langurs (Semnopithecus schistaceus), a foregut fermenter for which fruits and leaves dominate the diet at different times of the year. Materials and Methods: We collected data on feeding time per food item for 21 unprovisioned adult langurs at Ramnagar, Nepal, for 1 year using instantaneous sampling (773 observation hours). We combined these data with relative sugar and tannin content of food items to estimate diet content. We collected rainfall data to distinguish the wet season (May–September) from the dry season (October–April). We collected soil samples from consumption and control sites to test for pH and sodium, potassium, magnesium, and calcium concentrations. Results: Langurs consumed soil from two sources: termite structures (in almost all months) and river banks and beds (mainly in the dry season). Soil feeding was not positively correlated with dietary tannin or sugar content (GLMM). Soil pH was not high enough to buffer stomach contents. Only sodium was significantly higher in consumed soil. Discussion The most likely function of geophagy was the acquisition of sodium. This conclusion is consistent with reports for other animals. Buffering stomach pH, an often‐suggested function for animals with ruminant‐like digestion, was not supported. Detoxification, often proposed for animals with a diet high in secondary compounds, was also not supported. [ABSTRACT FROM AUTHOR]