Elephas Maximus Research Articles

Digging Deeper: Understanding the Calf Burials Behaviour among Asian Elephants in North Bengal

Abstract This case study, inspired by the work of Kaswan and Roy, provides critical insights into the thanatological behaviour of elephants, specifically in the North Bengal landscape. It serves as an important resource for private sanctuary managers, elephant handlers, and conservationists worldwide, raising awareness of elephants’ intelligence, emotional depth, and strong bonds with their herd members. The study reveals a unique behaviour among elephants in a specific area, where they bury deceased calves in 2-foot-deep irrigation drains within tea gardens. This region, featuring fragmented forests, tea estates, and small towns, serves as a natural corridor for elephants. The calves are buried in a ‘leg-upright’ position, indicative of how the herd uses their trunks and legs to manipulate the bodies. Two calves died from fungal infections, while three faced respiratory failure, yet all were buried similarly. Contusion marks suggest the herd dragged the calves over a distance before burial, highlighting their collective handling of the bodies. This burial behaviour is likely driven by several factors, including the particularly strong mother-calf bond seen in elephants which may motivate the herd to engage in mourning and burial. The unique environmental conditions in North Bengal, combined with the elephants’ complex social and emotional behaviours, create a remarkable example of interspecies empathy and care, offering valuable lessons for global conservation and elephant management efforts. Information © The Authors 2025

“Decoding Ambiguity”: Asian Elephants’ (Elephas maximus) use previous experiences and sensory information to make decisions regarding ambiguity

“Decoding Ambiguity”: Asian Elephants’ (Elephas maximus) use previous experiences and sensory information to make decisions regarding ambiguity

When the trumpet blows: age-sex-related differences in the acoustic properties and contexts of high-frequency vocalizations of free-ranging Asian elephants

When the trumpet blows: age-sex-related differences in the acoustic properties and contexts of high-frequency vocalizations of free-ranging Asian elephants

Multi-Antigen Elephant Endotheliotropic Herpesvirus (EEHV) mRNA Vaccine Induces Humoral and Cell-Mediated Responses in Mice.

Background/Objectives: Elephant endotheliotropic herpesvirus (EEHV) causes lethal hemorrhagic disease (HD) in Asian and African elephants in human care and the wild. It is the leading cause of death for young Asian elephants in North American and European zoos despite sensitive diagnostic tests and improved treatments. Thus, there is a critical need to develop an effective vaccine to prevent severe illness and reduce mortality from EEHV-HD. We generated a multi-antigenic EEHV mRNA vaccine to address this need that encodes the EEHV1A-subtype glycoproteins gB, gH, gL, and gO. These conserved proteins are the entry machinery for several herpesviruses in the betaherpesvirus subfamily and elicit humoral and cellular immunity in naturally infected elephants. Methods: Outbred CD-1 mice were vaccinated with two doses of an mRNA vaccine comprising modified EEHV1A gB, gH, gL, and gO mRNAs encapsulated into lipid nanoparticles. Humoral and T-cell immunity was assessed three weeks after the first dose or three weeks after the booster dose using luciferase immunoprecipitation system assays and flow cytometry, respectively. Results: The CD-1 mice vaccinated once had detectable antibody titers against gB, gH, and gL that increased significantly three weeks after a booster dose. Activated CD4+ and CD8+ T cells secreting cytokines associated with a TH1 response were induced against all four glycoproteins. No adverse effects were observed following one or two doses of the vaccine. Conclusions: We found that gB, gH, gL, and gO as a multivalent vaccine stimulated robust humoral and cell-mediated immunity. This is a critical step for moving this candidate EEHV1A mRNA vaccine into clinical trials in Asian elephants.

SEROCONVERSION CAN PRECEDE CULTURE CONFIRMED DIAGNOSIS OF MYCOBACTERIUM TUBERCULOSIS INFECTION IN ASIAN ELEPHANTS (ELEPHAS MAXIMUS) BY DECADES.

Mycobacterium tuberculosis (M. tb) infection was diagnosed in 16 human-managed Asian elephants (Elephas maximus) at four different US facilities. A retrospective review was performed to collate information on serological test results and describe the timelines from exposure to an elephant known to be positive for M. tb, detection of antimycobacterial antibodies in the exposed elephant, and M. tb isolation from the exposed elephant to confirm diagnosis. Seroconversion was defined by a positive test result using ElephantTB STAT-PAK, multiantigen print immunoassay, or DPP VetTB assay for elephants (Chembio Diagnostic Systems, Inc). Fifteen elephants were adults (age ≥24 yr) at first seroconversion and 26 yr or older when confirmed by a positive M. tb culture. Six animals were diagnosed postmortem, and 10 were diagnosed antemortem by positive trunk wash (TW) culture. The interval between last known exposure to an M. tb-positive elephant and serological conversion was 8.5 yr (median; range 0-18 yr) in the eight animals that had not already seroconverted. The median time from seroconversion to isolation of M. tb was 2.8 yr in elephants diagnosed by TW culture (antemortem) compared with those diagnosed postmortem (median 1.2 yr). Of the 10 elephants diagnosed antemortem, four were seropositive for 14 or more yr (range 0-33 yr) prior to the M. tb-positive culture. The median number of negative TW samples submitted between seroconversion and diagnosis by culture was 16 (range 0-151 samples). In contrast, a median of 48 negative TW cultures and 10 yr elapsed (range 0-41 yr) between exposure and culture diagnosis. Although this descriptive report has limitations, these findings are useful for veterinarians faced with an M. tb-seropositive elephant. This report supports the recommendation of increasing TW surveillance if an elephant has a history of exposure to an M. tb-positive elephant and has multiple seropositive results.

Detection of subclinical EEHV infection in captive Asian elephants (Elephas maximus) in Peninsular Malaysia through a molecular approach

Detection of subclinical EEHV infection in captive Asian elephants (Elephas maximus) in Peninsular Malaysia through a molecular approach

Obesity Prevalence and Associated Factors in Captive Asian Elephants (Elephas maximus) in China: A Body Condition Assessment Study.

Obesity is a prevalent health issue among captive wildlife, but the obesity status of captive Asian elephants (Elephas maximus) in China has not been systematically investigated. This study assessed obesity in 204 captive Asian elephants across 43 facilities by recording seven potentially relevant variables: sex, age, daily feed supply, proportion of high-calorie feed, outdoor enclosure area, outdoor time, and foot disorders. Body condition was evaluated using visual scoring, revealing a high prevalence of overweight and obesity, particularly in zoo-kept elephants. Over 70% of captive Asian elephants in China were classified as overweight or obese. Statistical analysis indicated that insufficient outdoor time is likely a primary contributor to obesity among zoo elephants. We recommend extending outdoor time and regulating the supply of high-calorie feeds (e.g., fruits, vegetables, and pellets) to promote exercise and balance energy intake. Additionally, implementing positive reinforcement training for routine health checks, including foot exams and blood sampling, could improve data collection on elephant health and welfare, ultimately enhancing obesity management and overall animal well-being.

Two observations of rescue behavior in wild Asian elephants

Two observations of rescue behavior in wild Asian elephants

A review of herbaceous vegetation effect on mechanical properties of soil for enhancing slope stability

Abstract Slope instability is a critical issue that threatens infrastructure, human settlements, and the environment, with conventional stabilization methods often causing significant environmental disruption and incurring high costs. This study aims to explore the potential of native Southeast Asian plants, especially lemongrass (Cymbopogon citratus), vetiver grass (Chrysopogon zizanioides), elephant grass (Pennisetum purpureum), and alang-alang grass (Imperata cylindrica) to improve soil quality and prevent slope stability. The analysis focuses on their physical and mechanical properties to identify trends and advantages for slope reinforcement and sustainable ecological restoration in Southeast Asia. The findings highlight that lemongrass and vetiver grass demonstrate promising improvements in slope stability parameters, including friction angle, cohesion, and shear strength, making them highly effective for erosion control. Lemongrass shows the most pronounced benefits, while vetiver grass also provides substantial stabilization. In contrast, elephant grass and alang-alang grass offer less improvement in these parameters. The study suggests that future research should explore the hydraulic behavior of these species to better understand their effects on water infiltration, runoff, and soil moisture dynamics, which are crucial for comprehensive slope stability analysis.

Discovery of structurally diverse sesquiterpenoids from Streptomyces fulvorobeus isolated from Elephas maximus feces and their antifungal activities

Thirty-six structurally diverse sesquiterpenoids, including caryolanes (1–12), germacranes (13–16), isodaucane (17), cadinanes (18–22), epicubenols (23, 24), oplopanane (25), pallenanes (26, 27), and eudesmanes (28–36), were isolated from the fermentation broth of Streptomyces fulvorobeus derived from Elephas maximus feces. Pallenane is a kind of rarely reported sesquiterpene with a distinctive C5/C3 bicyclic skeleton and was firstly found from microbial source. The structures of fifteen new compounds (1–4, 13–15, 17, 18, 22, 23, 25–28) were established through detailed spectroscopic data analysis, which included data from experimental and calculated ECD spectra as well as Mosher’s reagent derivative method. Compound 34 exhibited moderate antifungal activity against Cryptococcus neoformans and Cryptococcus gattii with MIC values of 50 μg/mL. It effectively inhibited biofilm formation and destroyed the preformed biofilm, as well as hindered the adhesion of Cryptococcus species. The current work would enrich the chemical diversity of sesquiterpenoid family.Graphical

Adivasi (Tea Tribe) worldviews of living close to wild Asian elephants in Assam, India.

In Assam state, northeastern India, human-elephant conflict mitigation has included technocentric measures, such as installation of barriers, alternative livelihoods, and afforestation. Such measures treat conflict as a technical problem with linear cause-effect relations and are usually ineffective over the long term because they do not consider how historical conditions have shaped present interactions between humans and elephants. Human-elephant encounters in South Asia, including in Assam, have arisen from colonial and postcolonial land-use policies, ethnic relations, and capital extraction. To disentangle these relations, we conducted ethnographic fieldwork in Udalguri district of Assam among the Adivasi (Tea Tribe) to examine their interactions with wild elephants. Through socioecological ruptures, caused by displacement and deforestation, Adivasi (Tea Tribe) and elephant lives have intersected through space and time. Adivasi (Tea Tribe) life narratives and observations of daily encounters with elephants revealed that their interactions are multifaceted and motivated by multiple factors. Myths and oral testimonies revealed that the community has created conceptualizations of the elephant by closely observing their behavior, especially their movements, diets, vocalizations, and interactions with humans. These conceptualizations are filled with vignettes of shared marginalized lives, caused by the loss of homeland, food poverty, and uncertain ways of living. The empathy, expressed by the Adivasi (Tea Tribe), highlights ways of living with elephants that are affective and reach beyond technocentric interventions. For Adivasi (Tea Tribe) members, cohabitation could thus be achieved by living close to elephants as uneasy neighbors. Concepts of cohabitation, we suggest, could be harnessed to inform conservation policy and bring into focus the critically important-and yet often underutilized-values, encompassed by bottom-up, place-centric understandings of what elephants are and how coexistence may be possible in increasingly anthropogenic landscapes.

Domestication and Human/Wildlife Mutualism

In this study, I discuss recent studies of human/wildlife mutualisms and suggest that several cases considered to represent domestication that has arisen through commensalism would be better considered as examples of mutualism between humans and various wild species. Species discussed include the only domesticated carnivores: cats (Felis sylvestris) and wolves (Canis lupus and C. dingo). I also discuss species over which there is considerable debate about whether they are domesticated or not: African (Loxodonta) and Asiatic elephants (Elphas). All of these species’ interactions include niche construction on the part of both species and influence human evolution at least a cultural level. I further argue that most contemporary domestic species currently exist in mutualistic relationships with humans because even though all of these species have been selected to benefit humans, all domestica species have also benefitted in terms of increased global and local population sizes and from more secure living conditions than can be found in their wild ancestors.

Unlocking insights: Mahout's perceptions and practices in managing Elephant Endotheliotropic Herpesvirus (EEHV) infection among captive Asian elephants in Surin province, Thailand.

Surin, situated in the northeastern region of Thailand, has earned the reputation of being an "elephant village" due to its high captive elephant population and unique tradition of elephant rearing. However, the continuous occurrence of elephant endotheliotropic herpesvirus (EEHV) infection poses a significant threat to elephants, particularly the young ones. This study investigated various aspects of EEHV-related elephant care among ninety-two mahouts at the Surin Elephant Kingdom Project. This study used semi-structured interviews and observations to assess the mahouts' knowledge, attitude, and practice (KAP scores) toward EEHV transmission, prevention, and management. The result revealed knowledge and practice scores below expectations, indicating an insufficient understanding the nature of disease and preventive measures. However, the mahouts exhibited awareness of the severity of the disease and factors contributing to transmission risk. Regarding the relationship among KAP scores, a positive correlation was observed at a low level (p < 0.05) between the knowledge and practice scores. Interestingly, approximately 55% of the survey respondents were confident that their elephants would not receive EEHV, leading to inadequate prevention measures. From the result, it is crucial to provide comprehensive knowledge about the nature of the disease and preventive measures to all mahouts. This education should emphasize the importance of early monitoring signs, appropriate weaning age, and preventing viral transmission practices. The KAP survey offers valuable insights that can identify areas requiring improvement and guide the development of effective and targeted disease prevention programs within the specific population. Therefore, it is recommended that the KAP survey should be employed in other parts of the country where the elephant management system differs.

Water-hose tool use and showering behavior by Asian elephants

Since Jane Goodall's famous observations of stick tool use by chimpanzees,1 animal tool use has been observed in numerous species, including many primates, dolphins, and birds. Some animals, such as New Caledonian crows, even craft tools.2,3 Elephants frequently use tools4,5 and also modify them.6 We studied water-hose tool use in Asian zoo elephants. Flexibility, extension, and water flow make hoses exceptionally complex tools. Individual elephants differed markedly in their water-hose handling. Female elephant Mary displayed sophisticated hose-showering behaviors. She showed lateralized hose handling, systematically showered her body, and coordinated the trunk-held water hose with limb behaviors. Mary usually grasped the hose behind the tip, using it as a stiff shower head. To reach her back, however, she grasped the hose further from the tip and swung it on her back, using hose flexibility and ballistics. Aggressive interactions between Mary and the younger female elephant, Anchali, ensued around Mary's showering time. At some point, Anchali started pulling the water hose toward herself, lifting and kinking it, then regrasping and compressing the kink. This kink-and-clamp behavior disrupted water flow and was repeated in several sessions as a strict sequence of maneuvers. The efficacy of water flow disruption increased over time. In control experiments with multiple hoses, it was not clear whether Anchali specifically targeted Mary's showering hose. We also observed Anchali pressing down on the water hose, performing an on-hose trunk stand, which also disrupted water flow. We conclude that elephants show sophisticated hose tool use and manipulation. VIDEO ABSTRACT.

Unveiling the Hidden Causes: Identifying the Drivers of Human-Elephant Conflict in Nilgiri Biosphere Reserve, Western Ghats, Southern India.

Since the human population is growing beyond the earth's ability to sustain it, more people are being brought into contact with wildlife, leading to increasing human-wildlife conflict. The Asian elephant, a wide-ranging megaherbivore, is being increasingly threatened by human-elephant conflict [HEC]. Its conservation depends on identifying the causes of HEC and implement measure to mitigate the HEC effectively. We studied the drivers of HEC among five forest divisions in Western Ghats, India, that support a high density of elephants across Asia. Comparing the last six years' data on HEC with 26 ecological covariates in the GLMM framework, we identified spatiotemporal variations and drivers of crop, and property damages and human casualties. Spatially, HEC was highest in the territorial division and lowest in those declared as Protected Areas earlier. The comparison of crop damage with covariates showed that crop damage decreased with the grass biomass index, elephant density, extent of dry-thorn, and deciduous habitats, and forest range area, while it increased with adult male % and forest range perimeter. Similarly, the property damage by elephants increased with crop damage frequency and human settlement/cultivation area, but decreased with grass biomass, forest range area, and deciduous habitat area. Human casualties due to elephants increased with property damage, ambient temperature, and forest range perimeter, but decreased with grass biomass. Overall, the decrease in HEC with grass biomass, and the increase in HEC with human settlement and forest range perimeter indicate that anthropogenic pressure that decreases the grass biomass and degrades the habitat is the likely root cause of HEC, and minimizing it would reduce overall HEC.

Genetic Diversity and Evolutionary Biology of Indian Wildlife- A Review

The genetic diversity and evolutionary biology of Indian wildlife, emphasizing the critical role of genetic variability in ensuring species adaptability and long-term survival. India is one of the world’s megadiverse countries, home to a wide range of unique flora and fauna spread across its biodiversity hotspots, including the Western Ghats and the Eastern Himalayas. However, rapid habitat fragmentation, deforestation, and poaching have severely impacted the genetic health of many wildlife species, leading to reduced gene flow, population bottlenecks, and increased inbreeding. This has heightened the risk of extinction for small, isolated populations such as the Asiatic lion and the Great Indian bustard. Genetic studies using advanced genomic tools have provided key insights into the population structure, phylogenetic relationships, and adaptive potential of species like the Bengal tiger, Asian elephant, and snow leopard. Conservation strategies, including genetic rescue, habitat corridors, and the use of captive breeding programs, are recommended to preserve genetic diversity and prevent further genetic erosion. Technological advances, such as non-invasive sampling and bioinformatics, are transforming wildlife research, enabling more precise and less intrusive genetic monitoring. The integration of genetic data into conservation policies and practices is essential for developing targeted management plans that maintain the evolutionary potential of Indian wildlife.

Development of a welfare assessment tool for tourist camp elephants in Asia.

Approximately one-third of Asian elephants are managed under human care, participating in educational, cultural, religious, and tourist activities. Management conditions vary considerably among venues, raising questions about whether welfare needs are consistently being met, particularly for Asian tourist camp elephants. To evaluate the well-being of elephants engaged in tourist activities, an evidence-based tool is needed for routine assessments to identify potential welfare risks, aid in the development of better camp standards, and enable caretakers to address specific concerns. While many animal welfare tools exist, none have been designed to consider specific environments and management practices faced by elephants living and working in tourist camps. Using direct observations and interviews, the Elephant Welfare Assessment Tool (EWAT) was developed for tourist camp elephants using the Five Domains Model as a framework. Measures were selected based on peer-reviewed literature, existing standards and guidelines, and opinions from animal welfare experts working with zoo and tourist camp elephants. The EWAT differs from existing tools by including criteria on work activities and restraint methods (e.g., chaining and ankus use), factors common in Asia but not often encountered by western zoo elephants. Measures were scored using a 0-2 Likert Scale. The tool was tested in Thailand and determined by calculating a content validity index (CVI) and conducting inter-rater and test-retest reliability tests. The initial tool included 18 animal-based and 21 resource-based measures across four domains: Nutrition (n = 5), Environment (n = 14), Health (n = 10), and Behavior and Mental State (n = 10). Index scores of content validity (CVI) (Item CVI (0.83), Scale CVI/Average (0.98), and Scale CVI/Universal (0.89)) were high. Measures scoring less than 0.83 were removed: the opportunity to mate, the mahout-elephant relationship, and mahout job satisfaction. The final tool consisted of 42 questions related to 36 measures, including 18 animal-based and 18 resource-based measures within the Nutrition (n = 5), Environment (n = 11), Health (n = 10), and Behavior and Mental State (n = 10) domains. Intraclass correlation coefficients (ICC) for inter-rater reliability (0.78-0.90, p < 0.05) and test-retest (0.77-0.91, p < 0.05) analyses conducted at two camps showed good agreement. This new assessment tool (EWAT) is a context-specific, holistic method designed to offer a practical means of conducting individual and institutional-level assessments of elephant welfare in tourist camps. It is based on the Five Domains Model using reliable and validated animal- and resource-based measures, data collection through direct observation and interviews, and a numerical scoring system. The tool includes several criteria applicable to tourist rather than zoo venues to make it more relevant to the challenges faced by working elephants in Asia.

Do elephants really never forget? What we know about elephant memory and a call for further investigation.

Despite popular culture's promotion of the elephant's ability to "never forget," there is remarkably limited empirical research on the memory capacities of any living elephant species (Asian, Elephas maximus; African savanna, Loxodonta africana; African forest, Loxodonta cyclotis). A growing body of literature on elephant cognition and behavioral ecology has provided insight into the elephant's ability to behave flexibly in changing physical and social environments, but little direct evidence of how memory might relate to this flexibility exists. In this paper, we review and discuss the potential relationships between what we know about elephant cognition and behavior and the elephants' memory for the world around them as they navigate their physical, social, and spatial environments. We also discuss future directions for investigating elephant memory and implications for such research on elephant conservation and human-elephant conflict mitigation.

Histomorphological features of pulmonary tuberculosis in Asian elephants (Elephas maximus)

Tuberculosis in Asian elephants usually shows involvement of lungs and associated lymph nodes. Grossly, the affected lobes of lungs reveal circumscribed lesions of varying sizes with central areas of caseation and necrosis. This report documents histomorphological features of pulmonary tuberculosis in six Asian elephants. The important cell types present were lymphocytes, foamy macrophages, epithelioid macrophages and Langhan’s type of giant cells. In addition, caseation necrosis, fibrotic capsule, and mineralisation (calcification) were also observed. Characteristic features of tuberculoid granulomas observed in the six cases showed similarities with other species. The six cases showed varying proportions of the seven defined features but all features were present together only in one case Keywords: Granuloma, histopathology

Attitudes towards causes of and solutions to conflict between humans and Asian elephants

AbstractMany Asian elephant populations inhabit fragmented human‐dominated landscapes. Human–elephant conflict (HEC) has intensified in such regions, resulting in the deaths of hundreds of people and elephants each year. Controversy between stakeholders then arises as people debate the merits of HEC mitigation approaches, stifling progress. We conducted a survey to evaluate the opinions of experts, farmers and others who have and have not experienced HEC (n = 611), on the causes of HEC, the importance of, conservation of and co‐existence with elephants, and on the acceptability and effectiveness of potential HEC mitigation methods. Analysis of variance and the Potential for Conflict Index showed that all groups agreed with nine of the 10 causes of HEC assessed, on average. All respondent groups had mostly positive attitudes towards the importance and conservation of elephants. However, farmers exposed to HEC disagreed that people should co‐exist with elephants and supported the view that elephants should be removed from human habitats. All groups agreed on the acceptability and effectiveness of electric fencing, early warning systems with infrasonic call detectors, Global Positioning System collars and geophones. However, there was disparity in views between the experts and other stakeholder groups on the acceptability and effectiveness of restricting elephants to protected areas, and translocation of problem elephants to protected areas away from their capture site or to wild elephant holding grounds. While similar views between stakeholders on many subjects are encouraging for elephant conservation, the disparities identified should be given greater attention when planning HEC management programs to minimize conflict between stakeholders.