Birth Peak Research Articles

LABOR DURATION IS DEFINED BY THE TIME OF DAY OF LABOR INDUCTION.

Spontaneous labor and birth peak during the late evening and early morning hours, indicating an endogenous rhythm in labor onset and birth. We hypothesize that the time-of-day of labor induction will define labor duration and the risk of cesarian section. In a retrospective study of pregnant women who were induced for labor (n =3,688), time-of- day of labor induction was studied across maternal phenotypes. Survival analysis and Cox Proportional Hazards model were used to identify differences in time-to-birth as a result of inducing labor at a specific time-of-day. Labor induction was circadian (p<0.05, Lomb-Scargle test), with a gradual lengthening in labor duration when labor induction was initiated later in the day, peaking at 23:00 hours (average labor duration of 20.72 hours) as compared to induction at 5:00 hours (average labor duration of 14.74 hours, p<0.01, Kruskal-Wallis test). The optimal time-of-day of labor induction was conditioned by maternal phenotype with significant differences in probability of giving birth as a result of the time-of-day labor was induced for nulliparous obese (p<0.05, Two-way ANOVA), and parous obese women (p<0.05). Labor duration in response to induction is circadian, with the shortest labor duration when induced during early morning hours. The optimal time-of-day of labor induction is conditioned by maternal phenotype and should be considered as a labor management practice.

Effects of extrinsic and intrinsic factors on parturition and reproductive output in wolverines

AbstractOne of the selective advantages of delayed implantation in carnivores is the flexibility to decouple the time between mating and parturition, allowing both to occur when conditions are most favorable. Terrestrial carnivores with delayed implantation have evolved reduced maternal energy expenditure through shorter gestation length, smaller neonates, and smaller litters, with a possible linkage between maternal body condition and time of birth or litter size. Using data on wolverine (Gulo gulo) females and cubs from management removals covering the entire latitudinal gradient of the Scandinavian population in 2001‐2022, I assessed the effect of extrinsic and intrinsic factors on variation in parturition date and litter size. Timing of parturition varied over 2 months, where 90% of the litters were born between 5 February and 11 March, with a birth peak on 23 February. Females living in winter grazing pastures of semi‐domestic reindeer (Rangifer tarandus) gave birth earlier than those outside, and along an elevation gradient parturition date was delayed at higher altitudes. I did not find evidence of an effect of latitude on parturition date. Furthermore, older females had greater odds than younger females of having litters with 3 cubs rather than 1 cub. To minimize the risk of harvesting lactating females, management regulations should implement harvest seasons that extend no longer than the end of January.

Fertility policy changes, maternal and foetal characteristics and birth timing patterns at a tertiary referral centre in Beijing: a ten-year retrospective study

ObjectiveThis study aimed to explore the impacts of the changing national fertility policy on maternal and fetal characteristics, and birth timing patterns and provide a basis for the management of...

Which month to give a birth? The analysis on birth seasonality of China

A series of medical and biological studies have identified a strong link between the season during which a child is born and early childhood development and adult health. While providing an explanation for the seasonal determinants of birth remains one of the key challenges for demographers, understanding seasonal birth peaks and troughs can inform both public health planning and efforts to prevent childhood diseases. The seasonality of births varies across and within countries. Nonetheless, there has been scant research into the seasonality of births in China. This study takes an in depth look at the seasonal fluctuations in China’s births since 1960 and investigates the effects on seasonality of several key factors such as parity, residence (urban or rural area), and changes to fertility policies. Traditionally, winter has been the peak season of births in China, while spring and summer have been lean seasons, a pattern which is quite different than patterns in Europe and the United States. After 1990, the sweeping implementation of one-child policy and the wider use of modern contraceptives among Chinese women prompted a fundamental shift in the seasonality of births, with the deviation of births from month to month gradually diminishing over time. People's self-control may serve as a key determinant accounting for such seasonal changes. First births exhibit pronounced and steady seasonality, while second and subsequent births follow a vague seasonal pattern, suggesting that later births are more likely affected by self-choice and self-intervention. The analysis also reveals that the monthly distribution pattern of second births experienced a dramatic change following the roll-out of the selective-two-child policy and the Universal Two-child Policy in 2014 and 2016, changes that reflects the adjustments people made to achieve their fertility plans under the new policy.

Unveiling demographic and mating strategies of Panthera onca in the Pantanal, Brazil.

We conducted the first long-term and large-scale study of demographic characteristics and reproductive behavior in a wild jaguar (Panthera onca) population. Data were collected through a combination of direct observations and camera trapping on a study area that operates both as a cattle ranch and ecotourism destination. Jaguars exhibited two birth peaks: April/May and October/November, that are the end and the beginning of the wet season in the Pantanal, respectively. The average litter size was 1.43 ± 0.65. Single cubs made up a total of 65.7% of the births, and we found a slight predominance of females (1.15:1 ratio) in litters. The mean age at independence was 17.6 ± 0.98 months, with sex-biased dispersal, with all males (n = 27) leaving the natal home range and 63.6% of females exhibiting philopatry. The interbirth intervals were 21.8 ± 3.2 months and the mean age at first parturition was 31.8 ± 4.2 months. Our results estimated a lifetime reproductive success for female jaguars of 8.13 cubs. Our observations also indicate that female jaguars can display mating behavior during cub rearing or pregnancy, representing 41.4% of the consorts and copulations recorded. We speculate that this behavior has evolved as a defense against infanticide and physical harm to the female. To our knowledge, this is the first time that such behavior is described for this species. All aggressive interactions between females involved the presence of cubs, following the offspring-defense hypothesis, that lead to territoriality among females in mammals, regardless of food availability. In the face of growing threats to this apex predator, this work unveils several aspects of its natural history, representing a baseline for comparison with future research and providing critical information for population viability analysis and conservation planning in the long term.

Circadian Rhythm of Childbirths and Maternal and Neonatal Prognosis at the Yaound&amp;#233; Central Hospital

Background: The circadian variation of childbirths has been described by several authors around the globe. De Graaf showed that hospital childbirths at night were associated with increased perinatal mortality and adverse perinatal outcome. To improve obstetric care, we carried out this study to evaluate the circadian rhythm of childbirths and to assess the outcome following variations in the time of childbirths during the day. Methods: It was a cross-sectional descriptive study at the Yaoundé Central Hospital (YCH), over a two years period. We collected data from files of women who delivered from the 1st of January 2017 to 31st December 2018. We included files of women who delivered at least at 28 weeks of pregnancy. We excluded files of those who delivered by elective caesarean section, those whose hour of delivery was not noted and those who delivered before reaching the hospital. Sociodemographic, obstetrical characteristics, and immediate prognosis were recorded. Data were entered into excel, then analysed with SPSS v23 software. Tools used to appreciate our results were means, median, number, percentage, P, and OR with its 95% confidence interval. The difference in p is significant if p is less than 5%. Results: We analyzed 6041 files bearing the time of birth. Childbirths took place at all hours of the day, but the times of the day where the highest numbers of births were recorded were 10, 11, 12, 13 (that’s 1pm), 14 (that’s 2 pm), 15 (that’s 3 pm), 16 (that’s 4 pm), 17 (that’s 5 pm) and 23 (that’s 11 pm) hours, with respectively 224 (3.7%), 277 (4.6%), 256 (4.2%), 265 (4.4%), 207 (3.4%), 255 (4.2%), 228 (3.8%), 216 (3.6%) and 226 (3.7%) births. The peak of births was at 11 am while the time of day where the lowest number of births was recorded was 6 pm, with 175 (2.9%) births. The mean age of participants was 27.34 ± 6.03 years with extremes of 13 and 49, with 87.6% between 20 to 39 years. Sociodemographic characteristics of participants, prematurity and bleeding during delivery, had no dependence on the time of delivery. Perineal tear, duration of observation, Apgar score of the newborn, birthweight, delivery mode, health personnel who performed the delivery, and episiotomyseemed to be influenced by the time of delivery. Daily shifts were not independently associated with the poor Apgar score (0 - 6) at 5 mins, when adjusted for all other factors (p = 0.109). Conclusion: Childbirths were more frequent between 10 am and 5 pm. The period where episiotomy was most performed is the same as when there was macrosomia childbirth. Tears of the perineum are more frequent between 2 pm and 10 pm. There was no independent association between Daily shifts and poor Apgar score. The poor APGAR score would be more related to low birth weight.

The impact of alpha male replacements on reproductive seasonality and synchrony in white‐faced capuchins ( Cebus imitator )

Objectives Reproductive seasonality is typically associated with ecological factors, but it can also be related to social factors, such as alpha male replacements (AMR). Such events can produce distinct birth peaks outside of the ecological peak, potentially increasing hardship for mother and infant and ultimately reducing fitness. We examined the impact of AMRs on birth seasonality, birth synchrony, and infant survival in the Santa Rosa population of white-faced capuchins (Cebus imitator). Materials and Methods We analyzed 33 years of data on seven capuchin groups to test whether AMRs and births occur seasonally and whether birth seasonality changes following AMRs. Using sliding window analysis, we tested whether ecological conditions predict births in future months. We also tested whether birth period affects infant survival and likelihood of infanticide. Results AMRs shift birth seasonality from the ecological birth peak in the early wet season (late May–July) to a social birth peak during the late dry season (March–May), but they do not affect synchrony. In addition, we found that being born in the social peak significantly decreases infant survival relative to individuals born in the ecological and nonpeak periods. Discussion These findings suggest that Santa Rosa's predictable seasons can provide conception cues for female capuchins, but AMRs disrupt this ecological timing of conceptions. We suggest the increased infant mortality associated with the social birth peak is related to seasonal factors, including water scarcity and varying resource availability, and increased risk of infanticide, as the social birth peak overlaps with the AMR peak.

Analysis of the male annual antler cycle, reproductive behavior and spotted fawn presence in the tropical white-tailed deer

The rutting season of the white-tailed deer (Odocoileus virginianus) is seasonal in North America, but in tropical latitudes it occurs year-round with peaks locally variable. Reproductive cycle of this species in Costa Rica is variable, clearly seasonal in San Lucas Island but continuous with two birth peaks in Palo Verde and Santa Rosa national parks in northwestern Costa Rica. In Hacienda y Refugio de Vida Silvestre Curú in the Nicoya Peninsula, a site south of these parks but in a different life zone, we observed males with hard antlers in 2015 but only from July to November. We therefore hypothesized that white-tailed deer have a continuous reproductive cycle during the year in Curú because the rainfall pattern is the same as in Palo Verde and Santa Rosa. We visited Curú every month and recorded the status of white-tailed deer antler growth: nubs, velvet, and hard, from January 2016 to December 2019. We also recorded other rut behaviors and the presence of spotted fawns. We recorded 1,134 observations of the status of antler growth, 13 observations on reproductive behavior and 133 observations of spotted fawns. The antler cycle was seasonal in the four years of study. Male antler casting took place from mid-November to mid-February and the growth of new antlers began in mid-December and lasted until mid-March. Velvet shedding occurred in April, May and June, and by July males had hard antlers. The rutting season lasted three months from mid-June to mid-August. Small spotted fawns were observed from the middle of the dry season to the beginning of the rainy season. All this highly contrasts with the reproduction pattern observed in Santa Rosa. Lack of seasonal variation in the photoperiod is likely an important factor that allows deer to reproduce throughout the year in these protected areas, but this variation does not exist in Curú either, where the species is seasonal. The reproductive patterns of white-tailed deer in Central and South America may have evolved in response to seasonal fluctuations in specific food availability, competition, or predation, all of which may be directly related to rainfall patterns. Greater knowledge of the link between rainfall patterns and food availability for deer would be of great help to further our understanding of factors driving the reproduction cycle of the White-tailed deer.

Reproductive seasonality in the Baka Pygmies, environmental factors and climatic changes.

Reproductive seasonality is a phenomenon common to human and animal populations and driven by, among others, climatic variables. Given the currently changing climate and its impacts on both the environment and human lives, the question arises of its potential effects on reproductive seasonality. Few studies have specifically explored the seasonality of reproduction among hunter-gatherers and anyone investigated how current climate change might affect this phenomenon. In this study we addressed reproductive seasonality in the Baka Pygmy living in African rain forests. Since reproductive seasonality can be linked to weather patterns, we explore this possibility. However, climatic variables driving weather patterns have changed over the years, so we assessed whether this has influenced the Baka reproductive pattern. Based on 34 years of written birth records and oral questionnaires from 13 years of systematic fieldwork, we observed a bimodal birth pattern with two birth peaks at 6-month intervals. Our results demonstrate that precipitation at conception or at birth potentially has effects, respectively negative and positive on the monthly number of births; and temperature has a role in controlling other variables that do affect the reproductive pattern. Changing weather patterns appear to be affecting the reproductive seasonality in the Baka, suggesting that attention needs to be given to the influence of global climate change on forager societies.

Fitness effects of seasonal birth timing in a long-lived social primate living in the equatorial forest

Reproductive seasonality is the norm in mammals from temperate regions but less common at lower latitudes, where a broad diversity of reproductive phenology strategies is observed. Our knowledge of the evolutionary determinants shaping this diversity remains fragmentary and may reflect high phenotypic plasticity in individual strategies. Here we investigated the ecological determinants and fitness consequences of variation in birth timing across the annual cycle in a social primate endemic to the Congo basin, the mandrill, Mandrillus sphinx , which breeds seasonally. We further examined traits that modulate this variation within and across individuals. We used 9 years of ecological, life history and behavioural data from a natural population to characterize patterns of environmental and reproductive seasonality. We then investigated the consequences of variation in birth timing for pre- and postnatal offspring survival and maternal interbirth intervals. Finally, we studied the influence of within- (reproductive history and age) and between-individual (social rank) traits on variation in birth timing. We found that mandrills’ daily foraging time varied seasonally, with greater fluctuations for subordinate than dominant females. Birth timing was plastic, as females gave birth year round without detectable consequences for postnatal offspring survival. Giving birth within the birth peak, however, decreased interbirth intervals and probability of miscarriage. Finally, reproductive history and social rank mediated within- and between-individual variation in birth timing, respectively. Specifically, females that experienced a previous reproductive failure gave birth early in the next birthing season and dominant females bred less seasonally than subordinates, which may reflect their more even access to resources across the year. Overall, the selective pressures shaping mandrill reproductive seasonality differed from a classical scenario of seasonal fluctuations in resources limiting offspring survival. A complex interplay between social and ecological factors may thus determine within- and between-individual variation in phenology strategies of tropical and gregarious mammals. • Mandrills breed seasonally in an equatorial environment. • Dominant females breed less seasonally than subordinate ones. • Interbirth intervals are minimized when giving birth inside the birth peak. • Offspring survival is not affected by birth seasonality. • Miscarriage probabilities increase when conceiving late in the mating season.

Childbirths and the Prevalence of Potential Risk Factors for Adverse Perinatal Outcomes among Asylum Seekers in The Netherlands: A Five-Year Cross-Sectional Study.

This five-year cross-sectional study mapped the prevalence of several known risk factors for adverse perinatal outcomes in asylum-seeking women in The Netherlands. Characteristics of 2831 registered childbirths among residents of asylum seekers centers (ASCs) in The Netherlands from 2016 to 2020 were included. Results showed a high general and teenage birthrate (2.15 and 6.77 times higher compared to the Dutch, respectively). Most mothers were pregnant upon arrival, and the number of births was highest in the second month of stay in ASCs. Another peak in births between 9 and 12 months after arrival suggested that many women became pregnant shortly after arrival in The Netherlands. Furthermore, 69.5 percent of all asylum-seeking women were relocated between ASCs at least once during pregnancy, which compromises continuity of care. The high prevalence of these risk factors in our study population might explain the increased rate of adverse pregnancy outcomes in asylum seekers compared to native women found in earlier studies. Incorporating migration-related indicators in perinatal health registration is key to support future interventions, policies, and research. Ultimately, our findings call for tailored and timely reproductive and perinatal healthcare for refugee women who simultaneously face the challenges of resettlement and pregnancy.

Nursery habitat use patterns of the scalloped hammerhead shark, Sphyrna lewini, in coastal areas of the central Mexican Pacific.

This work aimed to characterize the nursery habitat use patterns of the scalloped hammerhead shark, Sphyrna lewini (SPL), in coastal areas of Jalisco and Colima, through the birth pattern, space-time distribution and relationship with environmental conditions. Information was combined from three sources: monitoring bycatch from the artisanal fishery, fishery-independent samplings, and acoustic tracking and monitoring. From September 2013 to May 2017, 408 juvenile SPL (41.6-100.1cm total length) were recorded. Births occurred between May and December (rainy-warmer season), within a radius of 2 km from river mouths in Marabasco, Navidad Bay, Rebalsito-Tecuan and Cuitzmala mainly in shallow (<20 m), turbid and soft-bottom areas. Some tagged SPL moved from Marabasco and Rebalsito to Navidad Bay. The peak of catch and births occurred in June-August. Tagged SPL remained near the river mouth in Rebalsito for up to 27 days, showing a mean residency index of 0.29, a home range of 5.55 km2 with a core area of 1.23 km2 located within a 1.5km radius from the river mouth. In December-January SPL left the river mouth areas and the catch was scarce until the following May-June, except in January 2016, when the catch was high due to El Niño 2015. SPL bycatch was significantly associated with temperature, precipitation and the Oceanic Niño Index.

Is there a Link between Preterm Birth and In Utero Exposure to Climate Change?

Aim: The aim of this study is to clarify if there is a link between preterm birth and temperature as a climate factor. Our study comes after a long period of clinical experience that rose the suspicion of a possible correlation between temperature variation and peaks of premature births. Materials and method: We conducted a retrospective study on the number of births registered at the “Dr. I.A. Sbarcea” Clinical Hospital of Obstetrics and Gynecology in Brasov in 2018 and 2019. Data related to premature birth was further correlated to climate information regarding Brasov area obtained from the National Administration of Meteorology, Romania and to results of fertility statistics made publicly available by the Romanian National Institute of Statistics. Results: Our study group included 99 premature births registered at “Dr. I.A. Sbarcea” Clinical Hospital of Obstetrics and Gynecology in Brasov in 2018 and 127 in 2019. The premature birth rate peaks in August for both years of study: 2018 and 2019. Statistical data processing shows there is significant correlation between in utero exposure to extreme temperatures and registration of peaks of premature births. Conclusion: Recognizing a pattern of the raise in the premature birth rate may help the healthcare system to cope with the increased demands of the pediatric care units in time periods marked by specific climate context. Easy recognition of climate conditions that can consequently lead to a peak in the rate of premature birth can be useful for medical staff and patients.

NDVI predicts birth seasonality in historical Baja California Sur, Mexico: adaptive responses to arid ecosystems and the North American Monsoon

ABSTRACT Birth seasonality is a phenomenon whereby populations can be characterized by a single month or season in which births peak. While non-human animal research suggests that seasonal birth-pulses are related to variation in climate and local energy availability, social scientists debate the mechanisms responsible for it in humans. Here we investigate the role of precipitation, temperature, and energy availability on seasonal conception and birth pulses using a historical dataset from the Baja California peninsula – a hot, arid desert that experiences seasonal climatic fluctuations associated with the North American Monsoon. Analyses suggest that 1) local energy availability had a negative relationship with conception pulses; and 2) birth pulses had a positive relationship with local energy availability and a negative relationship with temperature. Taken together, our analyses suggest that women timed conceptions when local energy availability was lowest (challenging expectations of conception rates as simply reflecting ecological influences on female fecundity), so that children were born during the seasonal “green-up” associated with the North American Monsoon. Given our results, we speculate that birth seasonality represents a form of traditional ecological knowledge to improve neonate health and wellbeing.

Blessing the rains down in Africa: spatiotemporal behaviour of the crested porcupine &lt;em&gt;Hystrix cristata&lt;/em&gt; (Mammalia: Rodentia) in the rainy and dry seasons, in the African savannah

The assessment of habitat selection and temporal patterns of activity rhythms is paramount for wildlife conservation. Studies on behavioural ecology of wild mammals are particularly challenging in tropical areas, mostly when involving rare or elusive species. Despite being a common species in Italy, the crested porcupine Hystrix cristata is threatened of extinction throughout most of its sub-Saharan range. All available information on the ecology of this species has been collected in Italy, whereas no data is present in the scientific literature on spatiotemporal behaviour of this large rodent in Africa. In this work, we attempted to determine habitat selection and temporal patterns of activity rhythms of the crested porcupine in northern Benin and neighbouring countries, through intensive camera-trapping. We collected a total of 146 records of crested porcupine, 91 in the dry season (October-March) and 55 in the rainy season (April-September). Porcupines used most habitats in proportion to their local availability, while selecting rock outcrop formations (possibly used as shelter sites) and avoiding open areas, wetlands and gallery forests. A mostly nocturnal behaviour was confirmed throughout the year, with some diurnal activity at the start and at the end of the rainy season. The importance of rains in determining birth peak has been also showed, with juvenile individuals always observed at the start and at the end of the rainy season. Full moon always inhibited activity of this large rodent, most likely evolved as an antipredatory behaviour to limit encounters with potential predators (common leopard Panthera pardus, spotted hyaena Crocuta crocuta and honey badger Mellivora capensis) and humans. Poaching pressure towards porcupines in West Africa is strong. Porcupines are killed for the traditional medicine, for their meat and because they are widely considered as a crop pest. This assessment should therefore be used as a basic tool to design conservation plans to preserve this rodent species in its native range.

Seasonal consumption of insects by the crested porcupine in Central Italy

Abstract Many herbivorous, granivorous and frugivorous rodents can integrate animal proteins in their diet, still for many of them no information is available on the importance of animal food sources. The crested porcupine, Hystrix cristata, is considered a strictly vegetarian rodent. It may integrate animal proteins through bone-gnawing, while the importance of insects in his diet is poorly known. In this study we assessed the presence of insects in the diet of this rodent in Central Italy by collecting 141 faecal samples along transects in 2016–2020. Hypogeal plant organs were the main component of the diet (absolute frequency = 50.38%; volume = 60.13%). Insects were detected only in 6.8% samples, only in February–March, at the annual birth peak for the crested porcupine. Insect consumption, although occasional, could be linked to the nutritional requirements of this rodent during lactation.

Reproductive seasonality in primates: patterns, concepts and unsolved questions.

Primates, like other mammals, exhibit an annual reproductive pattern that ranges from strictly seasonal breeding to giving birth in all months of the year, but factors mediating this variation are not fully understood. We applied both a categorical description and quantitative measures of the birth peak breadth based on daily observations in zoos to characterise reproductive seasonality in 141 primate species with an average of 941 birth events per species. Absolute day length at the beginning of the mating season in seasonally reproducing species was not correlated between populations from natural habitats and zoos. The mid-point of latitudinal range was a major factor associated with reproductive seasonality, indicating a correlation with photoperiod. Gestation length, annual mean temperature, natural diet and Malagasy origin were other important factors associated with reproductive seasonality. Birth seasons were shorter with increasing latitude of geographical origin, corresponding to the decreasing length of the favourable season. Species with longer gestation periods were less seasonal than species with shorter ones, possibly because shorter gestation periods more easily facilitate the synchronisation of reproductive activity with annual cycles. Habitat conditions with higher mean annual temperature were also linked to less-seasonal reproduction, independently of the latitude effect. Species with a high percentage of leaves in their natural diet were generally non-seasonal, potentially because the availability of mature leaves is comparatively independent of seasons. Malagasy primates were more seasonal in their births than species from other regions. This might be due to the low resting metabolism of Malagasy primates, the comparatively high degree of temporal predictability of Malagasy ecosystems, or historical constraints peculiar to Malagasy primates. Latitudinal range showed a weaker but also significant association with reproductive seasonality. Amongst species with seasonal reproduction in their natural habitats, smaller primate species were more likely than larger species to shift to non-seasonal breeding in captivity. The percentage of species that changed their breeding pattern in zoos was higher in primates (30%) than in previous studies on Carnivora and Ruminantia (13 and 10%, respectively), reflecting a higher concentration of primate species in the tropics. When comparing only species that showed seasonal reproduction in natural habitats at absolute latitudes ≤11.75°, primates did not differ significantly from these two other taxa in the proportion of species that changed to a less-seasonal pattern in zoos. However, in this latitude range, natural populations of primates and Carnivora had a significantly higher proportion of seasonally reproducing species than Ruminantia, suggesting that in spite of their generally more flexible diets, both primates and Carnivora are more exposed to resource fluctuation than ruminants.

Population persistence, breeding seasonality and sexual dimorphism in the red-necked wallaby

The red-necked wallaby (Notamacropus rufogriseus) has a broad geographic range along the eastern seaboard of Australia, but ecological research on the mainland subspecies has been limited. We aimed to assess long-term monitoring (1974 to 2017) of abundance at a site in the Grampians National Park in Victoria. Our second aim was to evaluate trap success, sexual dimorphism, breeding seasonality, longevity and home range size from intensive studies (between 2008 and 2017) at this site. The abundance of red-necked wallabies increased over time, showing no negative effect of the arrival of the swamp wallaby (Wallabia bicolor) in the 1970s. Red-necked wallabies were highly trappable: 64% of individuals were retrapped at least once, one was retrapped 38 times, and trap success did not vary seasonally. Red-necked wallabies showed high site-fidelity, with no instances of long-range movements and no sex bias in likelihood of remaining on site. One female was regularly resighted for almost eight years after her initial capture and one male lived to an estimated age of 20 years. All births occurred in the first half of the year, with a marked peak of births in February, and over three-quarters of births occurred in February and March. Red-necked wallabies were highly sexually dimorphic: the largest male (24.5kg) was nearly 10kg heavier than the largest female (15kg), and male home ranges were over five times larger than those of females.

Diet enrichment and the reproductive season of captive Sunda Porcupine (Hystrix javanica F. Cuvier 1823)

This study aimed to extend our current knowledge of Sunda porcupine reproductive biology with emphasis on environmental enrichment and the reproductive season. Tomato and bean sprout feeding able to increase sperm quantity, sperm motility, and viability, as well as increase FSH and estrogen hormone levels. Four pairs of captive Sunda porcupine were used. Two pairs (fed with fresh tomato and bean sprout, enrichment group) and two pairs as control. The birth rate of enrichment group higher (with twin litter per year) than that in control (only one litter per year). It indicated that tomato and bean sprout feeding affect the birth rate in Sunda porcupine. The recent study showed that captive Sunda porcupine births occurred throughout the year, with no more than 1-2 litter per year and are have no interbirth-interval. The birth peak of captive Sunda porcupine occurs between April to August. Biparental activities during birth occurred. However, the female spent 50% of the time with the newborn. There was no courtship behaviour throughout the first two or three months of life of the cub.

Sexual selection in the Kinda baboon

Due to wide variation in the presence and degree of expression of a diverse suite of sexually-selected traits, the tribe Papionini represents an outstanding model for understanding how variation in sexual selection pressures and mechanisms leads to trait evolution. Here, we discuss the particular value of Papio as a model genus for studies of sexual selection, emphasizing the presence of multiple mating systems, and differences in the expression of sexually-selected traits among closely-related species. We draw particular attention to the Kinda baboon (Papio kindae), a comparatively less-studied baboon species, by providing a primer to Kinda baboon morphology, genetics, physiology, and behavior. Based on observations of large group sizes, combined with low degrees of sexual dimorphism and large relative testis size relative to other baboon species, we test the hypothesis that Kinda baboons have evolved under reduced direct, and increased indirect, male–male competition. We present the first long-term data on wild Kinda baboons in Zambia. Kinda baboon females show seasonal peaks in births and reproductive receptivity, and males exhibit a queing-rather than contest-based dominance acquisition with long alpha-male tenure lengths. We finish by making a number of explicit testable predictions about Kinda baboon sexual signals and behaviors, and suggest that Kinda baboons have potential to offer new insights into the selective environments that may have been experienced during homininization.