Genetic analysis of endangered hog deer (Axis porcinus) reveals two distinct lineages from the Indian subcontinent

The hog deer (Axis porcinus) is an endangered cervid with drastic population declines. There are 2 recognized subspecies of hog deer: A. p. porcinus, ranging from Punjab Province in Pakistan, Nepal, and the Northern part of India to Myanmar, and A. p. annamiticus found in Indo-China, Thailand, Laos, Cambodia, and Vietnam. The current geographic range of A. p. annamiticus is still ambiguous. We analyzed variation in the mitochondrial DNA control region (mtDNA CR) to investigate the intra-species structure, differentiation, and demographic history of hog deer from Cambodia (Kratie Province), which we compared with the populations from India and Thailand. We also generated divergence time estimates using a concatenated dataset of complete Cyt b and partial CR. The CR data showed that Cambodian hog deer are genetically differentiated from the mainland Indian and Thai populations, forming a distinct basal clade. The time of divergence indicates that the Cambodian lineage split from the other 2 hog deer lineages around 0.51 Mya, during the Late Pleistocene. The results also suggest strong phylogeographic structure among hog deer: lineage A extends from Terai Arc (foothills of the Himalayas) to Assam, India (A. p. porcinus), lineage B from Manipur, India to Thailand (A. p. annamiticus), and lineage C is only known from Kratie Province, Cambodia. Lineage A exhibited a higher level of genetic diversity than lineages B and C, with recent demographic stability. Thus, the hog deer population in Kratie Province appears to be a distinct lineage that should be treated as an evolutionarily significant unit.

The population of the globally endangered hog deer (Axis porcinus) has declined severely across its geographic range. Intensive monitoring of its demographic and genetic status is necessary. We examined the demographic and genetic structure of a small hog deer population in Keibul Lamjao National Park (KLNP), located on the western fringe of the Indo-Burma biodiversity hotspot for conservation planning. The distribution pattern of hog deer in the Park was derived based on the presence/absence of faecal pellets in 1 km × 1 km grids. We used double-observer distance sampling method to derive the hog deer abundance and population structure and compared with previous data to derive the population trend. We determined the genetic diversity of the population through microsatellite screening and bottleneck detection. The overall pellet density was 0.34 ± 0.02 pellets km-2 restricted to only 22.34 ± 0.20 km2 area of the park. The estimated density of the deer in the park was 1.82–4.32 individuals km-2. The population showed a declining trend from 2006–08 (p < 0.05, R2 = 0.916) with 8% annum-1 and an increasing trend from 2003–2018 (p < 0.05, R2 = 0.9304) with 10% annum-1. The adult male-to-female ratio and fawn-to-doe ratio were 36.2 ± 1.9 males per 100 females and 16.5 ± 0.4 fawns per 100 females, respectively. The molecular examination suggested that the mean number of alleles at 23 loci was 2.70 ± 0.18, the observed heterozygosity (Ho) ranged from 0.26 to 0.63 (mean 0.42 ± 0.02), the expected heterozygosity (He) ranged from 0.23 to 0.73 (χ = 0.51 ± 0.03), and the polymorphic information content (PIC) ranged from 0.2 to 0.67 (χ = 0.43 ± 0.03) indicating a moderate level of genetic diversity. Although no bottleneck in the population was observed, the loss of genetic diversity may affect the evolutionary potential of the species at the site by limiting the selection flexibility. Conservation planning coupled with scientific management regime will help in the long term persistence of the population in the region.

Factors affecting forage selection by the endangered Eld's deer and hog deer in the floating meadows of Barak-Chindwin Basin of North-east India

Seasonal variations in the water quality of a tropical wetland dominated by floating meadows and its implication for conservation of Ramsar wetlands

Hog deer (Axis porcinus) are among the rarest animals in the world and are listed as "Endangered" on the International Union for Conservation of Nature’s Red List of Threatened Species. Protected areas in Nepal are home to large and stable populations of hog deer relative to other parts of hog deer range, but changes in predator abundance, human activities, and climate change could alter hog deer abundance. Reliable and efficient methods to assess hog deer population trends are therefore essential to monitor changes over time. Combined with data on population numbers, support from local communities towards hog deer conservation is important in identifying key threats and developing appropriate conservation strategies. Accordingly, this research integrated natural and social sciences to evaluate density estimation methods and community support for hog deer conservation within Shuklaphanta National Park (SNP), Nepal. Distance sampling along line transects is a common and relatively simple approach used to monitor hog deer populations in Nepal. Recent advances in technology, however, have enabled alternative approaches using data from remote-sensing cameras. Knowledge of the effectiveness of these two approaches could inform future monitoring efforts. Accordingly, I compared two methods for estimating the density of hog deer: distance sampling along line transects (n=17) and a random encounter model (REM) applied to data from remote-sensing cameras (n = 30). The density estimate produced by distance sampling (33.58 ± 8.48 individuals per km²) was more than double the estimate produced using the REM (12.95 ± 0.04 individuals per km²). Of the two methods, the estimate from the REM was more aligned with previous estimates of hog deer density. In addition, camera surveys facilitated the collection of data on multiple species, behaviour, and habitat use compared with line transects. However, despite requiring almost same amount of time for data collection, camera surveys proved to be more costly. These findings highlight the need for a comparison of these density estimation methods with established techniques such as mark-recapture or block counts, coupled with expanded survey efforts to assess the accuracy of estimates. To assess community support for hog deer conservation, I worked with research assistants to interview residents (n=30) from municipalities in the buffer zone surrounding SNP. Interview participants were knowledgeable about deer as a species group, but half of participants did not distinguish hog deer from other deer species. Most participants expressed positive attitudes towards hog deer conservation, especially in the context of promoting the local tourism economy around wildlife viewing. Participants explained that crop damage from deer has been largely mitigated by current management practices, such as fencing, but that additional fencing would further reduce conflicts. My findings revealed opportunities for collaboration between park managers and communities within the buffer zone, particularly around the development of the wildlife tourism industry and the design of management approaches such as fencing. Combined, my research provides guidance for future research and education efforts targeted at hog deer conservation.

Determination of resource based stocking density of wild ungulates living in the floating meadows of Keibul Lamjao National Park, India

Hog deer (Axis porcinus) is one of the least studied animal species in Pakistan. It belongs to Order Artiodactyla and the family Cervidae. IUCN classified Axis porcinus as an endangered species in 2008. The present study was conducted to investigate the effects of varying environmental exposure, genders, and seasonal changes on captive hog deer (A. porcinus) at Lahore Zoo, Safari Zoo, and Jallo Park in Lahore, Pakistan. Non-invasive techniques were used to monitor stress levels in hog deer. For sample collection, four definite months belonging to two seasons’ winter and summer were considered. A total of 48 urine and faecal samples were collected from both male and female hog deer. Seasonal fluctuations have been found to have a significant impact on faecal and urinary cortisol levels. Higher cortisol levels were found in both male and female hog deer in the summer season at all three visited sites. Fluctuations in environmental exposure at three research sites had a significant impact on faecal and urinary cortisol levels. Higher levels of cortisol were found in both male and female hog deer at Jallo park and Lahore Zoo, as compared to Safari Zoo. It was concluded that lower cortisol levels at Safari Zoo might be due to better environmental conditions and more flexible enclosure size and interaction of various species of deer. Temperature affected hog deer cortisol levels in summer, as higher levels were measured in summer compared to winter. In addition, sex did not predict any stress levels in hog deer. It has been suggested that a large enclosure size can control levels of cortisol in hog deer.

Hog Deer (Axis porcinus), the rarest of Sri Lanka’s four deer species, is listed as Critically Endangered (CR) in the 2012 National Red List of Sri Lanka. Despite its status, the species has been studied very little within the country. This study, therefore, seeks to evaluate the current conservation status of the Hog Deer in the Galle District. The research was conducted over the course of one year, from December 1st, 2021 to December 1st, 2022. A total of 246 randomly selected participants from seven divisional secretariats in the Galle District were surveyed using a questionnaire. Recent observations recorded 306 adult Hog Deer and 22 fawns. Over a span of one and a half years, 27 injured and disabled Hog Deer were brought to the Hiyare Biodiversity Education and Research Center. They are restricted to human-modified landscapes, which they utilize on a seasonal basis. The survey documented 175 confirmed Hog Deer locations. Their habitat is limited to a small region in the Galle District, between the Bentota and Gin rivers. Hog Deer is known to cause damage to three crop types: Cinnamomum verum, Oryza sativa, and various vegetables, with Cinnamomum verum being the most frequently damaged plant. However, both the questionnaire survey and crop damage assessments indicated that the damage to cinnamon was minimal. The Hog Deer face significant threats within their range in the Galle District. Therefore, community-based conservation programs, along with institutional involvement, are essential for ensuring the survival of this charismatic species in its last remaining stronghold.

The hog deer (Axis porcinus), an Endangered grassland specialist of South and Southeast Asia, occurs at low densities across much of its range due to habitat loss and fragmentation. In Corbett Tiger Reserve, populations are mainly restricted to isolated alluvial grasslands, with major declines following the submergence of prime habitat by the Kalagarh Dam in 1974. To document distribution and provide rapid count indices, a three-day reconnaissance survey (22-24 May 2025) was undertaken in all 12 forest ranges, covering 141 beats during peak activity hours (06:00-10:00 am). Direct sighting counts were made daily, with the highest tally used as an index of relative abundance. Hog deer were recorded in only four ranges, indicating a restricted distribution. A total of 189 individuals were recorded, with observations expressed as relative abundance indices (CTR 0.15 ind/km²; Dhikala 2.31 ind/ km²). Dhikala accounted for 175 individuals, concentrated in the Dhikala Chaur and Jalashay beats, underscoring the role of high-quality alluvial grasslands and perennial water. As a rapid count without detection correction, findings represent indices rather than true population estimates. Results highlight the need for grassland management, invasive species control, and habitat connectivity to ensure long-term conservation of hog deer in CTR.

The hog deer (Axis porcinus), an Endangered grassland specialist of South and Southeast Asia, occurs at low densities across much of its range due to habitat loss and fragmentation. In Corbett Tiger Reserve, populations are mainly restricted to isolated alluvial grasslands, with major declines following the submergence of prime habitat by the Kalagarh Dam in 1974. To document distribution and provide rapid count indices, a three-day reconnaissance survey (22-24 May 2025) was undertaken in all 12 forest ranges, covering 141 beats during peak activity hours (06:00-10:00 am). Direct sighting counts were made daily, with the highest tally used as an index of relative abundance. Hog deer were recorded in only four ranges, indicating a restricted distribution. A total of 189 individuals were recorded, with observations expressed as relative abundance indices (CTR 0.15 ind/km²; Dhikala 2.31 ind/ km²). Dhikala accounted for 175 individuals, concentrated in the Dhikala Chaur and Jalashay beats, underscoring the role of high-quality alluvial grasslands and perennial water. As a rapid count without detection correction, findings represent indices rather than true population estimates. Results highlight the need for grassland management, invasive species control, and habitat connectivity to ensure long-term conservation of hog deer in CTR.

Endozoochory by exotic mammalian herbivores could modify vegetation composition by facilitating the dispersal and establishment of exotic and native plant species. We examined the potential for endozoochoric dispersal of native and exotic plants by exotic hog deer (Axis porcinus) in south-eastern Australia. We quantified the germinable seed content of hog deer faecal pellets collected in five vegetation types within a 10,500-ha study area that was representative of their Australian range. Twenty exotic and 22 native species germinated from hog deer faecal pellets and significantly more native species germinated compared to exotic species. Seedlings of the encroaching native shrub Acacia longifolia var. sophorae emerged, but no native trees emerged and the percentage of grasses that germinated was low (11%). The species composition of germinants was similar among the five vegetation types. We estimated that the hog deer population in our study area could potentially disperse >130,000 viable seeds daily. Our study shows how an exotic mammal can disperse seeds from both native and invasive plants and highlights the need for endozoochory to be considered more widely in studies assessing the impacts of exotic mammals on plant communities.

Background/Objectives: The hog deer (Axis porcinus) is an endangered species facing significant threats from habitat loss and fragmentation, with only captive populations remaining in China. Expanding breeding programs and restoring wild populations are critical strategies for the species' conservation. Achieving this requires the development of an effective health database and the identification of molecular biomarkers for their physiological traits. Methods: In this study, we present the largest blood metabolomics dataset to date for captive hog deer, comprising 73 healthy individuals. We conducted targeted metabolomics to quantify blood hormone levels and untargeted metabolomics to characterize blood metabolic profiles, aiming to evaluate the associations of sex, age, and weight with metabolic profiles. Results: Our results reveal distinct growth patterns between females and males, with males reaching their body weight plateau at a larger size. We observed significant sex differences (p < 0.05) in blood hormones and metabolic profiles. Females exhibited higher levels of progesterone, hydroxyprogesterone, stress hormones (e.g., cortisol), and proline, while males had higher levels of testosterone, uric acid, phenylalanine, and guanidinosuccinic acid. Notably, body weight emerged as a more important factor than gender in explaining variations in the metabolome, particularly in males. Several blood biomarkers were identified as correlating with age and body weight. Specifically, blood progesterone levels in females were linked to both age and body weight, while in males, uric acid, prolylhydroxyproline, and 3-methylhistidine were associated with these factors. The potential significance of these results for the artificial breeding and conservation of hog deer were discussed. Conclusions: Our study provides a metabolic reference for identifying abnormal individuals and offers potential biomarkers for determining the gender, age, and body weight of hog deer. These findings may have significant implications for the artificial breeding and conservation efforts of the species.

The hog deer (Axis porcinus) is a small deer whose natural habitat is the wet or moist tall grasslands in South and Southeast Asia. Wild populations have dramatically decreased in recent decades. While wild hog deer were recently acknowledged to be extinct in China, a few captive populations have been maintained. In the present study, we successfully employed the restriction-site-associated DNA sequencing (RAD-seq) technique to generate a genome-wide profile of single-nucleotide polymorphisms (SNPs) in the captive population of hog deer from Chengdu Zoo, China (N = 11). Up to 4.7 million clean reads per sample were sequenced, and 11,155 SNPs and 8,247 haplotypes were simultaneously observed within more than 80% of sequenced individuals. In this population, the mean frequency of major alleles at each polymorphism site was 0.7903±0.0014, and the average nucleotide diversity (π) and inbreeding coefficient (FIS) were 0.3031±0.0015 and -0.0302±0.0062, respectively. Additionally, the Euclidean distance-based multidimensional scaling method revealed that the pairwise genetic relatedness was evenly distributed. However, the results of homologous searching by short reads did not provide any meaningful explanation of the phylogenetic relationship of hog deer, which should be further investigated. In conclusion, our results revealed current state of genetic diversity in this captive population of hog deer.Furthermore, these genome-wide SNPs would be useful for guiding the mating schedule to avoid sharp increase of inbreeding coefficient.

Context A wild population of non-native hog deer has established in the Gippsland region of Victoria, Australia, and there is particular concern about its impact on native vegetation in Wilsons Promontory National Park (WPNP). Since 2015, there has been annual culling of hog deer at WPNP to reduce deer abundances and impacts. Aims The aims of this study were to use a kinship approach based on genotyping to assess contemporary dispersal of hog deer across WPNP, by identifying close kin, to determine whether dispersal of deer into culled sites from unculled sites may affect the long-term success of management there. Differences in the dispersal of male and female hog deer were also investigated. Methods In total, 91 hog deer tissue samples were collected across WPNP and surrounding sites. Single nucleotide polymorphism (SNP) markers were sequenced, and a final dataset comprising 8275 SNPs was used for analysis. First-order, second-order, and intermediate relative pairs were identified, and the geographic distance between these pairs was assessed to determine inter-pair distances to infer dispersal. Spatial autocorrelation between male and female samples was evaluated to measure the effects of sex-biased dispersal. Key results Only seven second-order relative pairs were found across different sites, with a 30 km distance between the furthest pair observed. However, most inter-pair distances across sites were ~5–10 km. Analyses of sex-biased dispersal showed that movement by deer was not strongly influenced by one sex. Conclusions Although hog deer in WPNP are genetically similar, most relatives that were sampled were not widely dispersed. This suggests that there is limited dispersal of hog deer across this park. Implications Recolonisation of hog deer at culled sites via dispersal is likely to be infrequent in WPNP. Kinship analysis provides an effective method of assessing contemporary dispersal and could be applied to other species to assess fine-scale movement across landscapes.

Management practices/strategies to re-modulate the wild behaviour of animal species could increase their number in natural areas. The captive herd of hog deer showed slight changes from wild behaviour due to captive stress with no alteration in wild behaviour pattern except captive stress. Adult males (6), adult females (6) and fawns (6) were selected and observed round the clock for thirty days across season after one-hour interval on each activity. All subjects in hotter part of the day spent more time in sitting and rest. While, few hours of night in sleeping, resting and rumination. Fawn spent more time in sitting, resting, and hiding compared to adults. During wandering, they also spent some time in standing. It was noticed that all hog deer in herd not slept together but few of them remain active. Only male fighting was observed and maximum was noticed in August and September during breeding season. Hog deer were mainly crepuscular in feeding with irregular short intakes, and grazing on grasses present in enclosure. This study provides guideline to rehabilitate wild hog deer for better breeding management, conservation and raising practices.