Preliminary study on cranial measurements and sexual dimorphism in skull bones of gaur (Bos gaurus gaurus, Smith 1827)

Cranial measurements have been widely used in various studies in wildlife sciences, ranging from understanding predator ecology to wildlife forensics. However, detailed description of morphometry and sexual dimorphism of the skull of gaur Bos gaurus gaurus is lacking. The present study was undertaken to determine the sexual dimorphism based on the cranial measurements of gaur. A total of 12 individual gaur skulls of male (n = 6) and female (n = 6) were studied in the field from the naturally deceased animals between January 2018 and December 2021 in different ranges of Bandhavgarh tiger reserve (BTR), Madhya Pradesh, India. The skull measurements were analysed using univariate and multivariate statistics to determine whether cranial dimensions could be used to differentiate male and female skulls reliably. A total of 43 morphometrical parameters grouped into nine indices were calculated. Select morphometrical parameters viz PL, GFL, AKI, LBB, LFB, GBEE, GBAN, BPOP and GTCH were significantly different (p < 0.05) between sexes, whereas GBAN were significantly higher in female skulls. The measurements demonstrated that the skull of the gaur was dolichocephalic as the profile length and the otion to otion breath in both male and female were <75% of the length. Overall, 28 linear measurements of both the sexes were statistically significant (p < 0.05; <0.01). The calculated indices revealed that the foramen magnum index in the female gaur were significantly higher. In calculated cranial indices the facial index (a) was higher in female and facial index (b) were higher in males. The two important parameters, facial breadth in facial index (a) and the greatest breadth in facial index (b) were positively correlated, though facial index (a) was statistically not significant between the sexes. The greater inner length of the foramen magnum in female skull resulted in foramen being oval whereas it was circular in males. These parameters were decisive for sexual dimorphism, skull comparison and craniological studies. This study ascertained that the frontal index and skull index had no significant influence and were not good indices for discriminating skulls between male and female. Based on the Principal Component Analysis, it was found that skull of male and female gaurs exhibits differences in cranial morphology viz. cranial profile length or total length (PL) and the least inner height of the temporal groove (LIHT). The findings of the present study provide baseline information on various craniometrical measurements of skull of gaur, indices and parameters for sex identification that can be effectively used in understanding sex biased predation ecology, provide base line information to describe variation across its geographic range, and in identifying skulls recovered in wildlife offence cases.

Variation in water utilization by mammal diversity in Khao Phaeng Ma Non-hunting area, Thailand

Access to suitable water sources is important for mammals. This study aimed to compared mammal diversity and water use among water springs, standard artificial ponds, and water pans within the Khao Phaeng Ma Non-Hunting Area in 2020 and 2021. Two camera traps were installed at each water sources for 749 nights with a total of 12 camera traps of 6 water sources. A total of 19,467 photographs were recorded comprising 13,777 photographs of gaur (Bos gaurus, vulnerable and the most important species in the area), and 5690 photographs of other mammals. In the wet season, relative use was highest at standard artificial pond number 2, which is established in the forest plantation area (4 × 4 m spacing, 12-20 m height, and 60%-80 % crown cover) and has a high volume of water, and at water pan number 1, which mimics a natural water spring in the man-made grassland and can supply water to mammals throughout the year. In the dry seasons, relative use was highest at water pan numbers 1 and 2; at the same time, other water sources dried up. During the study period, the number of mammal species was highest at water pan number 1 (10 species, diversity index [H'] = 1.38), and water pan number 2 (11 species, H' = 1.75). Grazers and browsers, including gaur, sambar deer (Rusa unicolor), northern red muntjac (Muntiacus vaginalis), omnivores (e.g. wild boar, Sus scrofa), and Asian black bear (Ursus thibetanus), used the water pan in the artificial grassland and standard artificial pond in the forest plantation rather than the water spring in the dry evergreen forest. Beside forest types, the use of water springs was associated with water period (months), while the use of standard artificial pond and water pans was associated with water surface area, water depth, altitude, species diversity, and species richness, and number of mammals photographed. The results show that water pans were more suitable for utilization by mammals than are other water sources.

Coincidence of low genetic diversity and increasing population size in wild gaur populations in the Khao Phaeng Ma Non-Hunting Area, Thailand: A challenge for conservation management under human-wildlife conflict

The gaur (Bos gaurus) is found throughout mainland South and Southeast Asia but is listed as an endangered species in Thailand with a decreasing population size and a reduction in suitable habitat. While gaur have shown a population recovery from 35 to 300 individuals within 30 years in the Khao Phaeng Ma (KPM) Non-Hunting Area, this has caused conflict with villagers along the border of the protected area. At the same time, the ecotourism potential of watching gaurs has boosted the local economy. In this study, 13 mitochondrial displacement-loop sequence samples taken from gaur with GPS collars were analyzed. Three haplotypes identified in the population were defined by only two parsimony informative sites (from 9 mutational steps of nucleotide difference). One haplotype was shared among eleven individuals located in different subpopulations/herds, suggesting very low genetic diversity with few maternal lineages in the founder population. Based on the current small number of sequences, neutrality and demographic expansion test results also showed that the population was likely to contract in the near future. These findings provide insight into the genetic diversity and demography of the wild gaur population in the KPM protected area that can inform long-term sustainable management action plans.

Changes in Neuropeptide Prohormone Genes among Cetartiodactyla Livestock and Wild Species Associated with Evolution and Domestication

The impact of evolution and domestication processes on the sequences of neuropeptide prohormone genes that participate in cell–cell signaling influences multiple biological process that involve neuropeptide signaling. This information is important to understand the physiological differences between Cetartiodactyla domesticated species such as cow, pig, and llama and wild species such as hippopotamus, giraffes, and whales. Systematic analysis of changes associated with evolutionary and domestication forces in neuropeptide prohormone protein sequences that are processed into neuropeptides was undertaken. The genomes from 118 Cetartiodactyla genomes representing 22 families were mined for 98 neuropeptide prohormone genes. Compared to other Cetartiodactyla suborders, Ruminantia preserved PYY2 and lost RLN1. Changes in GNRH2, IAPP, INSL6, POMC, PRLH, and TAC4 protein sequences could result in the loss of some bioactive neuropeptides in some families. An evolutionary model suggested that most neuropeptide prohormone genes disfavor sequence changes that incorporate large and hydrophobic amino acids. A compelling finding was that differences between domestic and wild species are associated with the molecular system underlying ‘fight or flight’ responses. Overall, the results demonstrate the importance of simultaneously comparing the neuropeptide prohormone gene complement from close and distant-related species. These findings broaden the foundation for empirical studies about the function of the neuropeptidome associated with health, behavior, and food production.

Gaur genome reveals expansion of sperm odorant receptors in domesticated cattle

Background

The gaur (Bos gaurus) is the largest extant wild bovine species, native to South and Southeast Asia, with unique traits, and is listed as vulnerable by the International Union for Conservation of Nature (IUCN).

Results

We report the first gaur reference genome and identify three biological pathways including lysozyme activity, proton transmembrane transporter activity, and oxygen transport with significant changes in gene copy number in gaur compared to other mammals. These may reflect adaptation to challenges related to climate and nutrition. Comparative analyses with domesticated indicine (Bos indicus) and taurine (Bos taurus) cattle revealed genomic signatures of artificial selection, including the expansion of sperm odorant receptor genes in domesticated cattle, which may have important implications for understanding selection for male fertility.

Conclusions

Apart from aiding dissection of economically important traits, the gaur genome will also provide the foundation to conserve the species.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-022-08561-1.

Food and nutrition of Gaur (Bos gaurus C.H. Smith, 1827) at the edge of Khao Yai National Park, Thailand

The presence of gaur (Bos gaurus) at the border of Khao Yai National Park (KYNP) in Thailand has resulted in a dramatic increase in the number of individuals’ crop feeding. This study examines the feeding adaptations of gaur at the edge of the protected area and assesses whether gaur response to increased nutrient availability in crop plants compared to natural forage. During the day, gaur mostly utilized forest areas in KYNP and entered the agricultural areas at night. Gaur ate 43 natural forage species. Natural forage species contain high levels of crude protein and lipid, but they are found in small quantities and scattered areas when compared to crop plants, especially Zea mays L., that are available in large quantity and are heavily foraged on by gaur. However, greater understanding of the electivity index and nutrition of forage species along the edge of the protected area can be used to reduce the gaur-human conflict by keeping gaur in KYNP. Reducing the large monoculture areas that is the food sources of gaur along the edge may reduce or prevent gaur leaving the park and can be applied to advance conservation actions.

Ancient genomes reveal tropical bovid species in the Tibetan Plateau contributed to the prevalence of hunting game until the late Neolithic

Local wild bovids have been determined to be important prey on the northeastern Tibetan Plateau (NETP), where hunting game was a major subsistence strategy until the late Neolithic, when farming lifestyles dominated in the neighboring Loess Plateau. However, the species affiliation and population ecology of these prehistoric wild bovids in the prehistoric NETP remain unknown. Ancient DNA (aDNA) analysis is highly informative in decoding this puzzle. Here, we applied aDNA analysis to fragmented bovid and rhinoceros specimens dating ∼5,200 y B.P. from the Neolithic site of Shannashuzha located in the marginal area of the NETP. Utilizing both whole genomes and mitochondrial DNA, our results demonstrate that the range of the present-day tropical gaur (Bos gaurus) extended as far north as the margins of the NETP during the late Neolithic from ∼29°N to ∼34°N. Furthermore, comparative analysis with zooarchaeological and paleoclimatic evidence indicated that a high summer temperature in the late Neolithic might have facilitated the northward expansion of tropical animals (at least gaur and Sumatran-like rhinoceros) to the NETP. This enriched the diversity of wildlife, thus providing abundant hunting resources for humans and facilitating the exploration of the Tibetan Plateau as one of the last habitats for hunting game in East Asia.

The complete mitochondrial genome of Indian gaur, Bos gaurus and its phylogenetic implications

The gaur is the largest extant cattle species and distributed across South and Southeast Asia. Around 85% of its current global population resides in India, however there has been a gradual decrease in the gaur population over the last two decades due to various anthropogenic activities. Mitochondrial genome is considered as an important tool for species identification and monitoring the populations of conservation concern and therefore it becomes an obligation to sequence the mitochondrial genome of Indian gaur. We report here for the first time 16,345 bp mitochondrial genome of four Indian gaur sequenced using two different approaches. Mitochondrial genome consisted of 13 protein-coding genes, 2 rRNA genes, 22 tRNA genes, and a control region. Among the 37 genes, 28 were positioned on the H-strand and 9 were positioned on the L-strand. The overall base composition appeared to be 33.5% A, 27.2% T, 25.9% C and 13.4% G, which yielded a higher AT content. The phylogenetic analysis using complete mitochondrial genome sequences unambiguously suggested that gaur is the maternal ancestor of domestic mithun. Moreover, it also clearly distinguished the three sub species of B. gaurus i.e. B. gaurus gaurus, B. gaurus readei and B. gaurus hubbacki. Among the three sub species, B. gaurus gaurus was genetically closer to B. gaurus readei as compared to B. gaurus hubbacki. The findings of our study provide an insight into the genetic structure and evolutionary history of Indian gaur.

Weights of gaur (Bos gaurus) and banteng (Bos javanicus) killed by tigers in Thailand

The primary prey of tigers across much of South-East Asia has been depleted, reducing the ability of already limited habitat to support tigers. To better understand the extent to which two of the largest prey species, gaur (Bos gaurus) and banteng (Bos javanicus), contribute to the tiger's diet, we estimated the average size of these species killed by tigers. This information is needed to more accurately calculate biomass of these species in the tiger's diet and to devise strategies to increase tiger carrying capacity where habitat is fragmented and limited in west-central Thailand. We used temporally clumped locations of 24 satellite radio-collared tigers to identify their kill sites and obtained mandibles from 82 gaur and 79 banteng. Kills were aged by teeth eruption sequence, sectioning the M1 molar and counting cementum annuli. Of all gaur killed, 45.2% were adults; of all banteng killed, 55.7% were adults. The average weight of banteng killed was 423.9 kg, which was similar to the 397.9 kg average weight for gaur. The mean weight of both prey species is 3.5-4.5 times greater than the predicted 1:1 preferred prey to predator ratio. In the absence of medium-sized prey, killing these larger animals may be especially critical for female tigers provisioning nearly independent young when male offspring are already larger than the mother. This is the first study to present data on the average weights of gaur and banteng killed in South-East Asia, and these results suggest that these are key prey species to target in tiger prey recovery efforts.

Muscle transcriptome signature and gene regulatory network analysis in two divergent lines of a hilly bovine species Mithun (Bos frontalis)

A massive bovine, Bos frontalis, also known as Mithun or Gayal, found at higher altitude is very promising meat and milk animal. For candidate gene and marker discovery, RNA-seq data was generated from longissimus dorsi muscle tissues with Illumina-HiSeq. Such markers can be used in future for genetic gain of traits like feed conversion efficiency (FCE) and average daily gain (ADG). Analysis revealed 297differentially expressed genes (DEGs) having 173 up and 124 down-regulated unigenes. Extensive conservation was found in genic region while comparing with Bos taurus. Analysis revealed 57 pathways having 112 enzymes, 72 transcriptional factors and cofactors, 212 miRNAs regulating 71 DEGs, 25,855 SSRs, mithun-specific 104,822 variants and 7288 indels, gene regulatory network (GRN) having 24 hub-genes and transcriptional factors regulating cell proliferation, immune tolerance and myogenesis. This is first report of muscle transcriptome depicting candidate genes with GRN controlling FCE and ADG. Reported putative molecular markers, candidate genes and hub proteins can be valuable genomic resources for association studies in genetic improvement programme.