Fast and cost-effective age estimation in Bengal tiger and Asiatic lion: applicability of cementum analysis method

Age estimation methods, through cementum analysis, for wild animals are rarely developed in Southeast Asian Countries. In the present study, we describe the applicability of the cementum analysis technique for developing a fast (plus minus 1, 19 hours) and cost-effective age estimation method for Bengal tiger (Panthera tigris tigris) and Asiatic lion (Panthera leo persica) using incisor tooth. The I2 and I3 incisor teeth from the right mandible of a tiger and I2 and I3 from the left maxilla of a lion were used in the study. The longitudinal sections of the tooth were made using a low cost hand grinding technique on sand papers followed by decalcification and staining with hematoxylin. The cementum layers were counted under the microscope at 100X or 200X magnifications. Two cementum layers were observed in each of the I2 and I3 incisor tooth of tiger and six cementum layers were observed in each of the I2 and I3 incisor teeth of lion. The permanent incisors in tiger and lion erupt between 12-14 months; hence, we added 1 year to the counted number of cementum layers to estimate the final age of tiger and lion incisors. The absolute age of tiger and lion incisors was estimated to be of 2+1 years and 6+1 years, respectively. The same number of cementum layers in both incisors respective to the tiger and lion were observed. Therefore, we suggest (i) undertake the blind test and (ii) collect incisor teeth from naturally died or killed individuals for strengthening the database on the age of the wild population. This optimized method may be suitable for many carnivore species, applicable in wildlife forensic studies and can be used by researchers with minimum expertise, time, and funds requirements throughout the world.

Historical and current distribution ranges and loss of mega-herbivores and carnivores of Asia

Ecosystem functioning is dependent a lot on large mammals, which are, however, vulnerable and facing extinction risks due to human impacts mainly. Megafauna of Asia has been declining for a long, not only in numbers but also in their distribution ranges. In the current study, we collected information on past and current occurrence and distribution records of Asia’s megafauna species. We reconstructed the historical distribution ranges of the six herbivores and four carnivores for comparison with their present ranges, to quantify spatially explicit levels of mega-defaunation. Results revealed that historically the selected megafauna species were more widely distributed than at current. Severe range contraction was observed for the Asiatic lion, three rhino species, Asian elephant, tigers, and tapirs. Defaunation maps generated have revealed the vanishing of megafauna from parts of the East, Southeast, and Southwest Asia, even some protected Areas losing up to eight out of ten megafaunal species. These defaunation maps can help develop future conservation policies, to save the remaining distribution ranges of large mammals.

Luteinizing Hormone Effect on Luteal Cells Is Dependent on the Corpus Luteum Stage in Felids

The objective of this study was to investigate the effect of luteinizing hormone (LH) on steroidogenic luteal cells obtained from corpora lutea (CL) of the domestic cat and selected wild felids. Luteal cells were isolated enzymatically from CL at different developmental stages and cultured for two days in the presence and absence of 100 ng/mL LH, respectively. Functionality was assessed by progesterone (P4) accumulation in cell culture media determined by ELISA. In addition, steroidogenic function was confirmed using immunohistochemistry for 3β-hydroxysteroid dehydrogenase (HSD3B). The enzymatic method allowed for the isolation of mostly small luteal cells in all investigated felids. Treatment with LH resulted in an increase in P4 secretion of cultured luteal cells obtained from CL in the formation stage (African lion) and development/maintenance stage (domestic cat (p < 0.05), Javan leopard), whereas luteal cells from more advanced stages of luteal development (regression) responded moderately or not at all to LH stimulation (domestic cat, Asiatic golden cat, Asiatic lion). The protein signal for HSD3B on CL was visible until development/maintenance. In conclusion, this study shows that LH promotes P4 production in luteal cells only until the onset of regression, when morphological signs are visible on the CL of felids and HSD3B is no longer detectable.

Effects of faecal inorganic contents in accurate measures of stress and nutrition hormone in large felines: implications for physiological assessments in free-ranging animals

Non-invasive stress and nutritional hormones and their interactions are increasingly being used to monitor psychological and nutritional physiology in free-ranging animals at different ecological scales. However, a number of extrinsic and intrinsic factors including hormone-inert dietary materials, inorganic matters etc. are known to affect accurate hormone measures. Here we addressed the impacts of inorganic matter (IOM) on corticosterone and T3 measures in wild tiger (n=193 from Terai Arc landscape, India) and captive lion (n=120 from Sakkarbaug Zoological Garden, Gujarat, India) faeces and evaluated possible corrective measures. The wild tiger samples contained highly variable IOM content (9-98%, mostly with >40% IOM) compared to captive Asiatic lion (17-57%, majority with <40% IOM). We observed significant negative correlation between IOM content and tiger GC (r=−0.48, p=0.000) and T3 (r=−0.60, p=0.000) measures but not in captive lions (r=−0.05, p=0.579). Two corrective measures viz. removing samples with ≥80% IOM and subsequently expressing concentrations as per gram of organic dry matter (instead of total dry matter) reduced IOM influence on tiger GC and T3 measures without affecting lion GC results. The corrective measures bring out alterations in the tiger T3 results but no changes in GC results. As faecal IOM content is associated with specific behaviours of many carnivore species, our results emphasize the need to reduce IOM-driven hormone data variation for ecologically relevant interpretations for species conservation.

The role of kinship and demography in shaping cooperation amongst male lions

The influence of kinship on animal cooperation is often unclear. Cooperating Asiatic lion coalitions are linearly hierarchical; male partners appropriate resources disproportionately. To investigate how kinship affect coalitionary dynamics, we combined microsatellite based genetic inferences with long-term genealogical records to measure relatedness between coalition partners of free-ranging lions in Gir, India. Large coalitions had higher likelihood of having sibling partners, while pairs were primarily unrelated. Fitness computations incorporating genetic relatedness revealed that low-ranking males in large coalitions were typically related to the dominant males and had fitness indices higher than single males, contrary to the previous understanding of this system based on indices derived from behavioural metrics alone. This demonstrates the indirect benefits to (related) males in large coalitions. Dominant males were found to ‘lose less’ if they lost mating opportunities to related partners versus unrelated males. From observations on territorial conflicts we show that while unrelated males cooperate, kin-selected benefits are ultimately essential for the maintenance of large coalitions. Although large coalitions maximised fitness as a group, demographic parameters limited their prevalence by restricting kin availability. Such demographic and behavioural constraints condition two-male coalitions to be the most attainable compromise for Gir lions.

Effects of a combined enrichment intervention on the behavioural and physiological welfare of captive Asiatic lions (Panthera leo persica)

The endangered Asiatic lion (Panthera leo persica) is currently distributed as a single wild population of 670 individuals and ∼400 captive animals globally. Although the captive lions are major hope for the species’ long-term conservation through repatriation, their welfare status and management practises need research attention. To this end, we tested the efficacy of feeding, sensory and manipulable enrichment interventions on the welfare of Asiatic lions at the conservation breeding centre of Sakkarbaug Zoological Garden, Gujarat. We adopted a holistic approach by measuring physiological and behavioural responses of 35 captive Asiatic lions, divided into control (n=16) and test (n=19) groups. The test subjects approached feeding devices first and manipulable devices for a longer duration. Manipulable devices were used homogenously with two significant time peaks, but sensory devices were used sporadically throughout the day with no discernible peak usage. The control subjects remained unchanged in all welfare parameters compared to their pre-treatment levels. However, post-enrichment behavioural assessments showed higher behaviour diversity (95% increase from the baseline period), reduced enclosure zone bias (40.25% reduction) and aberrant repetitive behaviours (80.68%) in test samples. Similarly, faecal corticosterone measures showed lower stress levels in test samples (58% decrease), confirming significant improvement in all welfare indices than control groups. These results have universal applicability to assess welfare indices of other captive species in Indian zoos. We hope that the results will encourage zoo managers and regulatory agencies to improve animal welfare practices.

Building walls around open wells prevent Asiatic Lion Panthera leo persica (Mammalia: Carnivora: Felidae) mortality in the Gir Lion Landscape, Gujarat, India

The Asiatic Lion population has increased in the last three decades, which now occupies a large regional spread with six or more identified satellite populations in eight districts of Gujarat. An overlap of lion habitat with human-dominated landscape elements leads to an increase in lion-human interactions in these growing satellite populations. A high rate of lion mortality has been observed in the periphery of Gir in the last decade due to falls into open dug wells. These wells have been excavated for irrigation in the agricultural landscape of Gir. About 145 wild animals including lions have died due to accidental falls into open wells in past 10 years. It has been observed that construction of parapet walls around wells in some of the peripheral areas of Gir Sanctuary have prevented this accidental mortality at very low cost. To assess the efficiency of these measures we did a survey of 20 random villages in the Gir Lion Landscape to collect data on the types of wells that cause this uncalled-for mortality. The paper explores the reasons for the lions falling into wells in the agricultural areas outside the Gir Sanctuary. The survey has shown that the corridors used by lions and in the satellite population areas are high risk sites where more parapet walls should be built on a priority basis. From the year 2007 to 2018 more than 48,000 parapet walls have already been randomly built in the periphery of the Gir Sanctuary. Out of 130 identified wells, 90 were protected with parapet wall or iron net while, 32 were without parapet wall and rest eight were with unfinished parapet wall. Providing a scheme for building more parapet walls around prioritized open wells would be an effective step towards Asiatic Lion conservation in the Gir Lion Landscape. Our survey indicates that there has been no mortality of lions in those wells where parapet walls have been built.

Evaluation of human attitudes and factors conducive to promoting human–lion coexistence in the Greater Gir landscape, India

Coexistence of people and large carnivores depends on a complex combination of factors that vary geographically. Both the number and range of the Asiatic lion Panthera leo leo in the Greater Gir landscape, India, has increased since the 1990s. The challenge has been managing the success of conservation, with a particular focus on the spillover population ranging extensively in human-dominated landscapes. To understand the factors conducive to lion survival in this landscape, we undertook an interview-based survey. Overall, people expressed positive, tolerant attitudes towards lions. There was a distinct contrast between people's liking for lions (76.9% of respondents) compared to leopards (27.7%) in spite of greater depredation of livestock by lions (82.6%) than by leopards (17.4%). Younger people and respondents having greater awareness regarding lions expressed positive attitudes. Although community discussions on lions had a positive effect, there was no evidence that land-holding, management interventions, personal encounters with lions, or association of lions with religion affected attitudes. Respondents who had experienced livestock depredation tended to express negative attitudes. Respondents with positive attitudes towards lions favoured non-interventionist strategies for managing lions in the village areas. We advocate consideration of varied factors influencing tolerance of wildlife in conservation planning. We emphasize that site-specific human–wildlife conflict issues such as crop-foraging by wild ungulates and variation in attitudes towards different species should also be considered. Specifically, improved livestock management, motivation of local youth and their participation in awareness campaigns could all further strengthen the prevalent positive attitudes towards lions.

Long live the king: chromosome-level assembly of the lion (Panthera leo) using linked-read, Hi-C, and long-read data

Background The lion (Panthera leo) is one of the most popular and iconic feline species on the planet, yet in spite of its popularity, the last century has seen massive declines for lion populations worldwide. Genomic resources for endangered species represent an important way forward for the field of conservation, enabling high-resolution studies of demography, disease, and population dynamics. Here, we present a chromosome-level assembly from a captive African lion from the Exotic Feline Rescue Center (Center Point, IN) as a resource for current and subsequent genetic work of the sole social species of the Panthera clade. Results Our assembly is composed of 10x Genomics Chromium data, Dovetail Hi-C, and Oxford Nanopore long-read data. Synteny is highly conserved between the lion, other Panthera genomes, and the domestic cat. We find variability in the length of runs of homozygosity across lion genomes, indicating contrasting histories of recent and possibly intense inbreeding and bottleneck events. Demographic analyses reveal similar ancient histories across all individuals during the Pleistocene except the Asiatic lion, which shows a more rapid decline in population size. We show a substantial influence on the reference genome choice in the inference of demographic history and heterozygosity. Conclusions We demonstrate that the choice of reference genome is important when comparing heterozygosity estimates across species and those inferred from different references should not be compared to each other. In addition, estimates of heterozygosity or the amount or length of runs of homozygosity should not be taken as reflective of a species, as these can differ substantially among individuals. This high-quality genome will greatly aid in the continuing research and conservation efforts for the lion, which is rapidly moving towards becoming a species in danger of extinction.