A Comparison of Social Organization in Asian Elephants and African Savannah Elephants

Asian and African elephant species have diverged by ca. 6 million years, but as large, generalist herbivores they occupy similar niches in their respective environments. Although the multilevel, hierarchical nature of African savannah elephant societies is well established, it has been unclear whether Asian elephants behave similarly. Here we quantitatively compare the structure of both species’ societies using association data collected using the same protocol over similar time periods. Sociality in both species demonstrates well-defined structure, but in contrast to the African elephants of Samburu the Uda Walawe Asian elephants are found in smaller groups, do not maintain coherent core groups, demonstrate markedly less social connectivity at the population level, and are socially less influenced by seasonal differences in ecological conditions. The Uda Walawe Asian elephants, however, do maintain a complex, well-networked society consisting of ≥2 differentiated types of associates we term ephemeral and long-term affiliates. These findings imply we must broaden our recognition of multilevel social organization to encompass societies that fall along a gradient of nestedness, and not merely those that exhibit hierarchical nesting. This in turn suggests that multilevel structures may be more diverse and widespread than generally thought, and that phylogenetic comparisons within species-rich clades, such as that of primates, using the methods presented can provide fresh insights into their socioecological basis.     

Family Traditions for Mahouts of Asian Elephants

ABSTRACT

The mahout and elephant relationship is one of the oldest human—animal relationships, possibly beginning as far back as 5,000 years ago. Valued for their assistance in war and work, elephants were trained and managed using methods described in ancient Indian texts. The lifelong job of mahouts historically had a long apprenticeship, and was passed from father to son. In 1973, when the government in Karnataka, India, assumed ownership of the maharajah's elephants, Hindu and Muslim mahouts with their elephants were relocated to national forests and became employees of the Forest Department. Members of honey-gathering tribes (called tribals) began to be offered government jobs as mahouts. To assess the current patterns of family traditions with elephants among mahouts living within Nagarahole National Park, India, sixteen mahouts and four young assistants were interviewed, representing Hindu, Muslim, and tribal families. In all three cultures, almost all had been introduced to elephants by a father or other male relative; the mahouts' sons expected to be mahouts. Mahouts' sons regularly assisted and played an essential role in the management of female elephants. No examples of injuries to children were mentioned by mahouts, yet some mahouts and villagers had been killed or seriously injured by elephants. Family tradition played a major role for Hindus, Muslims, and tribals in the decision to work with elephants. The semi-captivity of, and traditional, structured work activities with, Asian elephants may afford some possible improvements for their welfare and human—elephant conflicts.     

圈养亚洲象的刻板行为初探

2011年1月、7月、10～12月,采用事件记录法记录并分析了成都动物园圈养的2只(1♀1 ♂)亚洲象的刻板行为发生频次(次·h-1)和持续时间.结果表明,在刻板行为类型及其时间分配格局中,雌象以摇头最多,占73.93％,而雄象则以刻板踱步最多,占69.58％.雌象和雄象的刻板行为的发生频次和持续时间均是下午(12:00～17:00)多于上午(9:00～11:00);刻板行为持续时间最长的时间段均是16:00～17:00,雌象和雄象的刻板行为发生频次和持续时间还存在个体差异性.     

Demographic Variables for Wild Asian Elephants Using Longitudinal Observations

Detailed demographic data on wild Asian elephants have been difficult to collect due to habitat characteristics of much of the species’ remaining range. Such data, however, are critical for understanding and modeling population processes in this endangered species. We present data from six years of an ongoing study of Asian elephants (Elephas maximus) in Uda Walawe National Park, Sri Lanka. This relatively undisturbed population numbering over one thousand elephants is individually monitored, providing cohort-based information on mortality and reproduction. Reproduction was seasonal, such that most births occurred during the long inter-monsoon dry season and peaked in May. During the study, the average age at first reproduction was 13.4 years and the 50^th percentile inter-birth interval was approximately 6 years. Birth sex ratios did not deviate significantly from parity. Fecundity was relatively stable throughout the observed reproductive life of an individual (ages 11–60), averaging between 0.13–0.17 female offspring per individual per year. Mortalities and injuries based on carcasses and disappearances showed that males were significantly more likely than females to be killed or injured through anthropogenic activity. Overall, however, most observed injuries did not appear to be fatal. This population exhibits higher fecundity and density relative to published estimates on other Asian elephant populations, possibly enhanced by present range constriction. Understanding the factors responsible for these demographic dynamics can shed insight on the future needs of this elephant population, with probable parallels to other populations in similar settings.     

Exposure of Asian Elephants and Other Exotic Ungulates to Schmallenberg Virus

Schmallenberg virus (SBV) is an emerging Orthobunyavirus, first described in 2011 in cattle in Germany and subsequently spread throughout Europe, affecting mainly ruminant livestock through the induction of foetal malformations. To gain a better understanding of the spectrum of susceptible species and to assess the value of current SBV serological assays, screening of serum samples from exotic artiodactyls and perissodactyls collected at the Living Collections from the Zoological Society of London (Whipsnade and London Zoos) and Chester Zoo was carried out. There was compelling evidence of SBV infection in both zoological collections. The competitive ELISA has proved to be applicable for the detection of SBV in exotic Bovidae, Cervidae, Suidae, Giraffidae and most notably in endangered Asian elephants (Elephas maximus), but unreliable for the screening of Camelidae, for which the plaque reduction neutralisation test was considered the assay of choice.     

Asian Elephants in China: Estimating Population Size and Evaluating Habitat Suitability

We monitored the last remaining Asian elephant populations in China over the past decade. Using DNA tools and repeat genotyping, we estimated the population sizes from 654 dung samples collected from various areas. Combined with morphological individual identifications from over 6,300 elephant photographs taken in the wild, we estimated that the total Asian elephant population size in China is between 221 and 245. Population genetic structure and diversity were examined using a 556-bp fragment of mitochondrial DNA, and 24 unique haplotypes were detected from DNA analysis of 178 individuals. A phylogenetic analysis revealed two highly divergent clades of Asian elephants, α and β, present in Chinese populations. Four populations (Mengla, Shangyong, Mengyang, and Pu’Er) carried mtDNA from the α clade, and only one population (Nangunhe) carried mtDNA belonging to the β clade. Moreover, high genetic divergence was observed between the Nangunhe population and the other four populations; however, genetic diversity among the five populations was low, possibly due to limited gene flow because of habitat fragmentation. The expansion of rubber plantations, crop cultivation, and villages along rivers and roads had caused extensive degradation of natural forest in these areas. This had resulted in the loss and fragmentation of elephant habitats and had formed artificial barriers that inhibited elephant migration. Using Geographic Information System, Global Positioning System, and Remote Sensing technology, we found that the area occupied by rubber plantations, tea farms, and urban settlements had dramatically increased over the past 40 years, resulting in the loss and fragmentation of elephant habitats and forming artificial barriers that inhibit elephant migration. The restoration of ecological corridors to facilitate gene exchange among isolated elephant populations and the establishment of cross-boundary protected areas between China and Laos to secure their natural habitats are critical for the survival of Asian elephants in this region.     

Special Relationships between Female Asian Elephants (Elephas maximus) in Zoological Gardens

Social relationships between female zoo elephants were analyzed on three different zoo groups. Interactions were defined as either affiliative or agonistic. The most frequent interactions were found to be touching of the partner's mouth, genital sinus, face and trunk. The calf was the individual involved in most social interactions. Placing the trunk tip into the partner's mouth is a well known behaviour, the correlation between this behaviour and aggression was analyzed and a further function is suggested. Aggressive behaviour was analyzed and the hypothesis derived that rank order has to be established and is flexible in a non-kin group. The hypothesis that Asian elephant females may form special relationships was tested and confirmed. The following behaviour patterns were determined as indicators of a special relationship: Spatial proximity, partner-specific reactions to arousal and to vocalizing, and omission of agonistic behaviour. An experiment confirmed the hypothesis that the removal of one member of a special relationship from the enclosure would elicit more arousal behaviour in the respective partner.     

Serodiagnosis of Tuberculosis in Asian Elephants (Elephas maximus) in Southern India: A Latent Class Analysis

Background

Mycobacterium tuberculosis, a causative agent of chronic tuberculosis disease, is widespread among some animal species too. There is paucity of information on the distribution, prevalence and true disease status of tuberculosis in Asian elephants (Elephas maximus). The aim of this study was to estimate the sensitivity and specificity of serological tests to diagnose M. tuberculosis infection in captive elephants in southern India while simultaneously estimating sero-prevalence.

Methodology/Principal Findings

Health assessment of 600 elephants was carried out and their sera screened with a commercially available rapid serum test. Trunk wash culture of select rapid serum test positive animals yielded no animal positive for M. tuberculosis isolation. Under Indian field conditions where the true disease status is unknown, we used a latent class model to estimate the diagnostic characteristics of an existing (rapid serum test) and new (four in-house ELISA) tests. One hundred and seventy nine sera were randomly selected for screening in the five tests. Diagnostic sensitivities of the four ELISAs were 91.3–97.6% (95% Credible Interval (CI): 74.8–99.9) and diagnostic specificity were 89.6–98.5% (95% CI: 79.4–99.9) based on the model we assumed. We estimate that 53.6% (95% CI: 44.6–62.8) of the samples tested were free from infection with M. tuberculosis and 15.9% (97.5% CI: 9.8 - to 24.0) tested positive on all five tests.

Conclusions/Significance

Our results provide evidence for high prevalence of asymptomatic M. tuberculosis infection in Asian elephants in a captive Indian setting. Further validation of these tests would be important in formulating area-specific effective surveillance and control measures.     

Unmanned Aerial Survey of Elephants

The use of a UAS (Unmanned Aircraft System) was tested to survey large mammals in the Nazinga Game Ranch in the south of Burkina Faso. The Gatewing ×100™ equipped with a Ricoh GR III camera was used to test animal reaction as the UAS passed, and visibility on the images. No reaction was recorded as the UAS passed at a height of 100 m. Observations, made on a set of more than 7000 images, revealed that only elephants (Loxodonta africana) were easily visible while medium and small sized mammals were not. The easy observation of elephants allows experts to enumerate them on images acquired at a height of 100 m. We, therefore, implemented an aerial strip sample count along transects used for the annual wildlife foot count. A total of 34 elephants were recorded on 4 transects, each overflown twice. The elephant density was estimated at 2.47 elephants/km² with a coefficient of variation (CV%) of 36.10%. The main drawback of our UAS was its low autonomy (45 min). Increased endurance of small UAS is required to replace manned aircraft survey of large areas (about 1000 km of transect per day vs 40 km for our UAS). The monitoring strategy should be adapted according to the sampling plan. Also, the UAS is as expensive as a second-hand light aircraft. However the logistic and flight implementation are easier, the running costs are lower and its use is safer. Technological evolution will make civil UAS more efficient, allowing them to compete with light aircraft for aerial wildlife surveys.     

Visual Cues Given by Humans Are Not Sufficient for Asian Elephants (Elephas maximus) to Find Hidden Food

Recent research suggests that domesticated species – due to artificial selection by humans for specific, preferred behavioral traits – are better than wild animals at responding to visual cues given by humans about the location of hidden food. \Although this seems to be supported by studies on a range of domesticated (including dogs, goats and horses) and wild (including wolves and chimpanzees) animals, there is also evidence that exposure to humans positively influences the ability of both wild and domesticated animals to follow these same cues. Here, we test the performance of Asian elephants (Elephas maximus) on an object choice task that provides them with visual-only cues given by humans about the location of hidden food. Captive elephants are interesting candidates for investigating how both domestication and human exposure may impact cue-following as they represent a non-domesticated species with almost constant human interaction. As a group, the elephants (n = 7) in our study were unable to follow pointing, body orientation or a combination of both as honest signals of food location. They were, however, able to follow vocal commands with which they were already familiar in a novel context, suggesting the elephants are able to follow cues if they are sufficiently salient. Although the elephants’ inability to follow the visual cues provides partial support for the domestication hypothesis, an alternative explanation is that elephants may rely more heavily on other sensory modalities, specifically olfaction and audition. Further research will be needed to rule out this alternative explanation.     

Endocrine Correlates of Musth in Free-Ranging Asian Elephants (Elephas maximus) Determined by Non-Invasive Faecal Steroid Hormone Metabolite Measurements

The occurrence of musth, a period of elevated levels of androgens and heightened sexual activity, has been well documented for the male Asian elephant (Elephas maximus). However, the relationship between androgen-dependent musth and adrenocortical function in this species is unclear. The current study is the first assessment of testicular and adrenocortical function in free-ranging male Asian elephants by measuring levels of testosterone (androgen) and cortisol (glucocorticoid – a physiological indicator of stress) metabolites in faeces. During musth, males expectedly showed significant elevation in faecal testosterone metabolite levels. Interestingly, glucocorticoid metabolite concentrations remained unchanged between musth and non-musth periods. This observation is contrary to that observed with wild and captive African elephant bulls and captive Asian bull elephants. Our results show that musth may not necessarily represent a stressful condition in free-ranging male Asian elephants.     

Circadian Rhythm of Salivary Cortisol in Asian Elephants (Elephas maximus): A Factor to Consider During Welfare Assessment

Elevated glucocorticoid levels during an extended time period might be a stress indicator in nonhuman animals. Therefore, knowledge of the circadian pattern of cortisol secretion is very important to correctly interpret data obtained for welfare assessment of animals in captivity through salivary cortisol. In order to define the circadian rhythm of salivary cortisol secretion in the Asian elephant (Elephas maximus), morning and evening saliva samples of 3 Asian elephants were collected and analyzed by radioimmunoassay. Significantly higher salivary cortisol concentrations were found in the morning than in the evening in all individuals. These results show that salivary cortisol of Asian elephants follows a diurnal pattern of secretion, which could be taken into account when using this methodology to assess welfare in captive Asian elephants.     

莫达非尼对睡眠剥夺条件下工作记忆的影响

目的:观察在睡眠剥夺条件下莫达非尼对工作记忆的改善作用,为此药在我军的应用策略提供实验依据。方法:18名健康男性志愿者,在两次睡眠剥夺实验中交叉服用莫达非尼和安慰剂,睡眠剥夺时间从第一天的07:00到第3d的07:00,并于第二天的0:00、12:00和第三天的0:00分别服用莫达非尼100mg或安慰剂。采用随机双盲设计给药,并在第一天的07:00、第二天的02:00和14:00以及第三天的02:00和07:00安排工作记忆测验。结果:工作记忆测验中,两组的反应时和正确率均有统计学差异(P<0.01),莫达非尼组的反应时要快于安慰剂组,正确率也要高于安慰剂组。莫达非尼对工作记忆的改善效果随着睡眠剥夺时间的延长而更趋明显。结论:莫达非尼对睡眠剥夺条件下个体的工作记忆有改善作用,是较为理想的睡眠剥夺对抗药物。     

Effects of Climate Change Drivers on Nitrous Oxide Fluxes in an Upland Temperate Grassland

Despite increasing interest in the patterns of trace gas emissions in terrestrial ecosystems, little is known about the impacts of climate change on nitrous oxide (N₂O) fluxes. The aim of this study was to determine the importance of the three main drivers of climate change (warming, summer drought, and elevated CO₂ concentrations) on N₂O fluxes from an extensively managed, upland grassland. Over a 2-year period, we monitored N₂O fluxes in an in situ ecosystem manipulation experiment simulating the climate predicted for the study area in 2080 (3.5°C temperature increase, 20% reduction in summer rainfall and atmospheric CO₂ levels of 600 ppm). N₂O fluxes showed significant seasonal and interannual variation irrespective of climate treatment, and were higher in summer and autumn compared with winter and spring. Overall, N₂O emissions showed a positive correlation with soil temperature and rainfall. Elevated temperature had a positive impact on mean annual N₂O fluxes but effects were only significant in 2007. Contrary to expectations, neither combined summer drought and warming nor the simultaneous application of elevated atmospheric CO₂ concentrations, summer drought and warming had any significant effect on annual N₂O fluxes. However, the maximum N₂O flux rates observed during the study occurred when elevated CO₂ was combined with warming and drought, suggesting the potential for important, short-term N₂O–N losses in enriched CO₂ environments. Taken together, our results suggest that the N₂O responses of temperate, extensively managed grasslands to future climate change scenarios may be primarily driven by temperature effects.     

在野象的警戒区里

野生动物大多有一定的警戒足巨离,人类一旦进入它们的警戒距离,它们就会做出必要的反应。野象伤人事件往往发生在野象的警戒区内。     

Effects of sports training on sleep characteristics of Asian adolescent athletes

Adolescents are predisposed to poorer quality of sleep and experience shortened sleep durations, with these trends being more pronounced amongst Asians. Even though sleep is crucial for athletic recovery, there is a dearth of the literature on the sleep patterns of Asian adolescent athletes. The purpose of this study was to examine the effects of different intensities of sports training on sleep patterns in adolescent athletes, and to describe novel sleep data and daytime sleepiness amongst Asian adolescents who were high-level athletes. Those athletes (age 14.8 ± 0.9 years) in higher-intensity sports showed significantly more deep sleep, less light sleep and waketime after sleep onset. Actigraphically determined bedtimes and waketimes were significantly delayed on weekends, when mean total sleep time was also significantly longer. There was a large effect for an increased daytime sleepiness in high-intensity sport athletes. These findings highlight the phenomenon of social jet lag in Asian adolescent student-athletes.     

Elephants facilitate impact of large predators on small ungulate prey species

Predators and megaherbivores have profound impacts on ecosystem structure and functioning. Following the reintroduction of apex predators (lion and spotted hyaena) into the Main Camp Section (Main Camp) of the Addo Elephant National Park (Addo – Eastern Cape, South Africa) populations of small (5–50 kg) prey species declined. Following the recent reintroduction of apex predators into the neighbouring Colchester Section, a similar decline in small prey species might have occurred. However, we predict that the dense nature of Thicket vegetation in Colchester has provided the small prey species a refuge from predation from the reintroduced apex predators. Using camera trap data collected over three years following the apex predator reintroduction into Colchester, we show that declines in small ungulate prey species have not taken place. The primary difference between these two sections at the time of the apex predator reintroduction was the state of the Thicket (dense vegetation type characteristic of both sections). Main Camp is characterized by fragmented Thicket that has been altered as a result of high elephant densities, whereas Colchester has intact Thicket following a long history of elephant absence. The fragmented Thicket in Main Camp allowed access to the Thicket habitats (as indicated by GPS collar data on lions), in which these small prey species reside, potentially increasing the predation on these species in Main Camp. The intact Thicket in Colchester, however, may provide a refuge away from the apex predators (and possibly meso-predators) for the small prey species. We suggest that the impact of predators on this prey community is conditional on the long history of ecosystem transformation by ecosystem engineers such as elephants.     

Devastating Decline of Forest Elephants in Central Africa

African forest elephants– taxonomically and functionally unique–are being poached at accelerating rates, but we lack range-wide information on the repercussions. Analysis of the largest survey dataset ever assembled for forest elephants (80 foot-surveys; covering 13,000 km; 91,600 person-days of fieldwork) revealed that population size declined by ca. 62% between 2002–2011, and the taxon lost 30% of its geographical range. The population is now less than 10% of its potential size, occupying less than 25% of its potential range. High human population density, hunting intensity, absence of law enforcement, poor governance, and proximity to expanding infrastructure are the strongest predictors of decline. To save the remaining African forest elephants, illegal poaching for ivory and encroachment into core elephant habitat must be stopped. In addition, the international demand for ivory, which fuels illegal trade, must be dramatically reduced.     

Forest Elephants: Tree Planters of the Congo

The abundance of large vertebrates is rapidly declining, particularly in the tropics where over-hunting has left many forests structurally intact but devoid of large animals. An urgent question then, is whether these 'empty' forests can sustain their biodiversity without large vertebrates. Here we examine the role of forest elephant ( Loxodonta africana cyclotis ) seed dispersal in maintaining the community structure of trees in the Ndoki Forest, northern Congo. Analysis of 855 elephant dung piles suggested that forest elephants disperse more intact seeds than any other species or genus of large vertebrate in African forests, while GPS telemetry data showed that forest elephants regularly disperse seeds over unprecedented distances compared to other dispersers. Our analysis of the spatial distribution of trees from a sample of 5667 individuals showed that dispersal mechanism was tightly correlated with the scale of spatial aggregation. Increasing amounts of elephant seed dispersal was associated with decreasing aggregation. At distances of<200 m, trees whose seeds are dispersed only by elephants were less aggregated than the random expectation, suggesting Janzen–Connell effects on seed/seedling mortality. At the landscape scale, seed dispersal mode predicted the rate at which local tree community similarity decayed in space. Our results suggest that the loss of forest elephants (and other large-bodied dispersers) may lead to a wave of recruitment failure among animal-dispersed tree species, and favor regeneration of the species-poor abiotically dispersed guild of trees.