Group size, sex and age composition of chital (Axis axis) and sambar (Rusa unicolor) in a deciduous habitat of Western Ghats

Knowledge of the social structure of a population is important for a range of fundamental and applied purposes. Group characteristics and population structure of chital (Axis axis) and sambar (Rusa unicolor) were studied in a deciduous habitat of Mudumalai Tiger Reserve, Western Ghats, India, during 2008-2009. Vehicle transects were monitored monthly to gather information on group-size and age-sex composition of chital and sambar. The average mean group size and crowding for chital and sambar was 13.1 ± 0.5 (n = 1020), 3.6 ± 0.2 (n = 377) and 33.3, 11.0 respectively. The average adult male:adult female:fawn ratio was 63.4:100:22.3 (n = 9391) and 43.9:100:23.7 (n = 1023) in chital and sambar respectively. The mean group size of chital and sambar varied significantly between seasons (Kruskal-Wallis test, p = <0.001). Peak fawning season was observed from February to May for chital and May to August for sambar. Group's sex-age composition influenced group formation in both species between seasons at different level. Adult male and fawn were the important predicting variables of change in group size. Skewed female sex ratio was probably due to selective male predation by large predators. Although fawning occurred throughout the year, both species showed seasonality in fawning. The above mentioned patterns differed between species depending upon their ecological adaptation in foraging strategies and habitat preference.     

Antler mineral composition of Iberian red deer <Emphasis Type="Italic">Cervus elaphus hispanicus</Emphasis> is related to mineral profile of diet

Previous studies have suggested that antlers are costly bone structures whose mineral composition may change depending on physiological and other factors. This study examined whether nutrition variation associated with deer management influences antler mineral composition and structural characteristics of whole antler. Mineral distribution and bone structure were examined in antlers from two groups of adult Iberian red deer Cervus elaphus hispanicus Hilzheimer, 1909. They were kept under different feeding regimes at an experimental deer farm and a game estate in southeastern Spain. Protein and mineral contents differed between the diet of captive deer and that of deer in the wild. Significant differences were found for Na, Mg, K and protein. Antler composition seems to reflect the diet, as antlers of deer differed in protein, Na, Mg and K, but not in total mineral content, Ca, Fe or Zn. Thus, management conditions related to nutrition are reflected on antler composition.     

The effect of cyproterone acetate on the antler cycle in red deer (Cervus elaphus L.)

The aim of the study was to test the effect of antiandrogen, cyproterone acetate (CA) on the antler cycle in the red deer (Cervus elaphus). CA was administered to three adult red deer stags (Edward, Fuks and Gacek) in weekly intervals. Edward and Fuks were given 600 mg + 600 mg of CA, whereas Gacek was given 600 mg + 300 mg. CA was injected during the hard antler phase: in mid-October (Edward), at the end of November (Fuks) and at the end of January (Gacek). CA caused the antler casting 17 to 22 days after the first injection. In all stags, the casting of antlers was followed by a period of intensive growth of new antlers. Edward was given CA at the end of October. This treatment was responsible for occurrence of the two antler cycles in the year of the experiment. When CA was administered during the middle of the hard antler phase an additional short antler cycle occurs followed by new antler growth. CA treatment in the later part of hard antler phase may cause a prolonged antler cycle.     

Seasonal variations in semen characteristics, semen cryopreservation, estrus synchronization, and successful artificial insemination in the spotted deer (Axis axis)

Ten adult male spotted deer were monitored over a 2-year interval to determine seasonal variations in testicular size, semen characteristics and serum testosterone concentrations, and to determine if there was an association between season and type of antler. Mean (+/-S.E.M.) testicular volume (118.8+/-4.6 cm(3)), serum testosterone concentration (1.2+/-0.1 ng/mL), semen volume (4.1+/-0.6 mL), sperm concentration (338.3+/-24.9 x 10(6) mL(-1)), percentage of morphologically normal sperm (79.1+/-2.8%), and percentage of motile sperm (66.5+/-1.5%) were higher (P<0.05) in hard antler deer (peaked from March to May) than in deer with velvet antlers or in deer in which the antler has been shed. Thus, March-May was considered the physiologic breeding season for these deer; at this time, all stags had hard antlers. Furthermore, a Tris-citrate-based semen extender containing 4% glycerol and 20% egg-yolk was adequate for cryopreservation of semen. Estrus was induced with an implant containing norgestomet, timed transcervical AI was done with fresh semen, and 3 of 10 females were pregnant at 60 days, with fawns born 120 (premature), 240 and 243 days after AI. These results were considered a model for the use of assisted reproductive techniques to conserve other critically endangered deer species of India.     

Internal architecture of pampas deer antlers differs in males allocated with and without females

Bone mineralization of antlers and the depth of the antler seal (the basal surface of the cast antlers) are positively related to testosterone concentrations. Pampas deer males that are in permanent contact with females have greater, heavier, and darker antlers than males that are isolated from them. The objectives were to determine if antler compact/spongy bone ratio, antler seal depth, and compact bone darkness are greater in pampas deer males permanently allocated with females than those in males isolated from them. Antlers from males permanently allocated with or without females were cut transversally in seven points and scanned, and the compact/spongy ratio was calculated. The pixel intensity of each image was determined with a software for image analysis. The coronet of the antler was cut longitudinally, and the height of the most prominent protrusion was measured. The compact/spongy ratio was greater in antlers from males that were in contact with females in the second tine (P?=?0.02) and tended to be great in the two other tines (P?=?0.06 and P?=?0.1, respectively). Compact bone pixel color was darker in males in contact with females than that in males isolated from females in two points (P?=?0.02 and P?=?0.05, respectively) and tended to do so in two more (P?=?0.055 and P?=?0.1, respectively). Antler seal convexity was also greater in antlers from males in contact with females (P?=?0.006). We concluded that permanent contact with females stimulated pampas deer males increasing compact bone portion of the antler tines, the seal depth size, and the darkness of the compact bone.     

Factors influencing seasonal and monthly changes in the group size of chital or axis deer in southern India

Chital or axis deer (Axis axis) form fluid groups that change in size temporally and in relation to habitat. Predictions of hypotheses relating animal density, rainfall, habitat structure, and breeding seasonality, to changes in chital group size were assessed simultaneously using multiple regression models of monthly data collected over a 2 yr period in Guindy National Park, in southern India. Over 2,700 detections of chital groups were made during four seasons in three habitats (forest, scrubland and grassland). In scrubland and grassland, chital group size was positively related to animal density, which increased with rainfall. This suggests that in these habitats, chital density increases in relation to food availability, and group sizes increase due to higher encounter rate and fusion of groups. The density of chital in forest was inversely related to rainfall, but positively to the number of fruiting tree species and availability of fallen litter, their forage in this habitat. There was little change in mean group size in the forest, although chital density more than doubled during the dry season and summer. Dispersion of food items or the closed nature of the forest may preclude formation of larger groups. At low densities, group sizes in all three habitats were similar. Group sizes increased with chital density in scrubland and grassland, but more rapidly in the latter—leading to a positive relationship between openness and mean group size at higher densities. It is not clear, however, that this relationship is solely because of the influence of habitat structure. The rutting index (monthly percentage of adult males in hard antler) was positively related to mean group size in forest and scrubland, probably reflecting the increase in group size due to solitary males joining with females during the rut. The fission-fusion system of group formation in chital is thus interactively influenced by several factors. Aspects that need further study, such as interannual variability, are highlighted.     

Habitat quality influences relative antler size and hunters’ selectivity in roe deer

Understanding factors affecting antler size, and the extent to which harvesting is selective for these traits, is important in order to address management strategies aimed to minimize the risk of negative evolutionary consequences. In an Alpine study area, we compared the phenotypic quality and the antler size of 2,725 male roe deer hunted in two regions differing for winter harshness and habitat quality, and evaluated whether the selective behaviour of recreational hunters was influenced by phenotypic quality and antler size. Antler length and antler circumference relative to both body mass and jaw length were larger in the region with more favourable climate and habitat conditions, indicating that here roe deer were able to allocate more resources to antler growth. The analysis of the temporal trends of harvest bags suggested that hunters did not select roe deer for their body mass or size, but instead for antler size. This resulted also in a preference for sub-adult and adult age classes, while yearlings were culled reluctantly, especially in the region where antlers were smaller. Our results indicate that environmental heterogeneity may influence the relative investment in antler growth. In this way, it may interact with the hunters’ preferences increasing the risk that recreational hunting of roe deer, which is a widespread practice in many European countries, might result in alteration of male age structure and possibly in directional artificial selection.     

Antler size provides an honest signal of male phenotypic quality in roe deer

Identifying factors shaping secondary sexual traits is essential in understanding how their variation may influence male fitness. Little information is available on the allocation of resources to antler growth in territorial ungulates with low sexual size dimorphism. We investigated phenotypic and environmental factors affecting both absolute and relative antler size of male roe deer in three contrasting populations in France and Sweden. In the three populations, we found marked age-specific variation in antler size, with an increase in both absolute and relative antler size between yearling and prime-age stages, followed by a decrease (senescence) for males older than 7 years. Antler size increased allometrically with body mass. This increase was particularly strong for senescent males, suggesting the evolution of two reproductive tactics: heavy old males invested particularly heavily in antler growth (potentially remaining competitive for territories), whereas light old males grew small antlers (potentially abandoning territory defense). Finally, environmental conditions had little effect on antler size: only population density negatively affected absolute antler size in one of the three populations. Antler size may therefore provide an honest signal of male phenotypic quality in roe deer. We discuss the implications of these results in terms of territory tenure and mating competition.     

Growth of the first antler in Iberian red deer (<Emphasis Type="Italic">Cervus elaphus hispanicus</Emphasis>)

In this study, we describe the process of pedicle and first antler growth in Iberian red deer (Cervus elaphus hispanicus) and document relationships among body development, maternal milk supply and composition, and maternal weight on the length of first antlers. Antler length of 53 males of Iberian red deer was measured every 2 weeks from birth to 20 months of age. Deer weight, age, and the date of occurrence of the major events during the antler growth cycle were also recorded. The first evidence of pedicle development occurred when the animals were 38.0 ± 0.6 weeks old and weighed 60.7 ± 0.9 kg. Antler cleaning took place at a mean age of 63.8 ± 0.7 weeks and a mean weight of 91.5 ± 1.8 kg. The antler growth period lasted 16.7 ± 0.4 weeks, and the cleaning period lasted 5.1 ± 0.4 weeks. First antler growth followed a sigmoid curve, reaching a final length of 38.3 ± 1.0 cm. Antler length was positively correlated with body weight during the antler growth cycle. Additionally, the final length of the first antler was related to total milk yield, date of antler growth initiation, body weight at 6 months of age, and the antler growth time interval.     

Numerical investigation of bone remodelling around immediately loaded dental implants using sika deer (Cervus nippon) antlers as implant bed

This study combines finite element method and animal studies, aiming to investigate tissue remodelling processes around dental implants inserted into sika deer antler and to develop an alternative animal consuming model for studying bone remodelling around implants. Implants were inserted in the antlers and loaded immediately via a self-developed loading device. After 3, 4, 5 and 6 weeks, implants and surrounding tissue were taken out. Specimens were scanned by μCT scanner and finite element models were generated. Immediate loading and osseointegration conditions were simulated at the implant-tissue interface. A vertical force of 10 N was applied on the implant. During the healing time, density and Young’s modulus of antler tissue around the implant increased significantly. For each time point, the values of displacement, stresses and strains in the osseointegration model were lower than those of the immediate loading model. As the healing time increased, the displacement of implants was reduced. The 3-week immediate loading model (9878 ± 1965 μstrain) illustrated the highest strains in the antler tissue. Antler tissue showed similar biomechanical properties as human bone in investigating the bone remodelling around implants, therefore the use of sika deer antler model is a promising alternative in implant biomechanical studies.     

Population dynamics and social organization of sambar (Rusa unicolor unicolor) in Horton Plains National Park,Sri Lanka

We estimated the population density and investigated the social organization of sambar (Rusa unicolor unicolor) in Horton Plains National Park (HPNP), Sri Lanka. Distance sampling was conducted along six strip transects every month for a period over 3 years (2018–2020) to estimate the density of the sambar population in grasslands of HPNP (9.4 km²), while the antler stage of males and the behavior of individuals were recorded to describe the population's reproductive stage and hence the social organization. Population density estimates showed relative stability over the 3 years and varied over the seasons but with consistent peaks from year to year with the highest population densities recorded in November–December (212.93 ± 25.38 animals/km² in 2018, 187.91 ± 28.51 in 2019, and 179.76 ± 31.85 in 2020). The highest percentage of males in hard antlers was observed from November through January, while the percentage of antlers cast sambar peaked from March to April each year. Hinds were observed with newborn calves throughout the year, but the highest number of newborn calves were recorded from July to August each year, while the number of calves counted each year varied from 210 to 267 individuals. The mean group size was variable throughout each year with the largest groups recorded from September to December (up to 52), the period accompanied by the most observations of mating and sparring behavior. Although on a tropical island, HPNP is situated on a rolling plateau landscape in the highlands, where sambar showed a degree of reproductive seasonality somewhat similar to temperate cervid species.     

Effects of public vs. private management on deer antler composition, mechanical and structural variables

Previous studies have shown that antler mineral composition reflects diet. Thus, management involving diet can influence both the mineral composition and mechanical properties of antlers. However, it is not known if reducing population density, which increases availability of food, can compensate mineral deficiencies arising from lack of minerals in plants and, ultimately, in the soil. The present study aimed at assessing if private management often involving a balanced food supplementation produced differences in antler properties compared to both public management and reference antlers from deer farms. We also examined if low population density in a National Park could compensate for mineral deficiencies found in antlers of other public reserves or else, antlers still differed in antler characteristics compared to supplemented deer in private game estates. We used 120 antlers from three public reserves, four private game estates and two deer farms as reference to assess antler composition, mechanical properties, size and structure. Public managed antlers had shorter length compared to private and reference ones, thinner cortex (CT), were less dense, had lower second moment of area (I) and work to fracture (W). In addition, they had content in ash, Ca, Mg, Na, S and Zn lower than antlers from private game estates. In contrast, antlers from public reserves had greater values of Young’s modulus of elasticity (E), Fe, Mn and Si. In most cases, antlers from private management and reference farms showed similar values. When comparing antlers from low population density in a National Park with antlers from private management, differences in antler length, CT, I and ash disappeared, but both differed still in density, E, bending strength, W and content in all minerals mentioned. In conclusion, low density can improve some structural variables, but it cannot compensate for mineral deficiencies whereas food supplementation can.     

Seasonal antler cycle in a herd of pampas deer (Ozotoceros bezoarticus) in Uruguay

To describe the yearling antler cycle of pampas deer bucks (Ozotoceros bezoarticus) 22 bucks and 72 antler cycles have been studied in a semi-captive population. Date of individual antler cast, first day on which the brow and the trez tine were observed, and day of the velvet shedding were registered. Time intervals (days) between first and second antler casts, between first antler cast and the brow tine observation, between brow and trez tines observation and from first antler cast to velvet shedding were calculated. The brow and the trez tine were first observed 22.8±0.6 and 45.9±0.9 days after the first antler cast. Velvet shedding was observed 103.3±2.1 days after the first antler cast. Both antlers casts were observed earlier in adult cycle bucks than in first antler bucks, although the interval between both casts was not different. The interval from the brow tine observation to the trez tine observation was shorter in first antler cycle bucks than in adults. As in other deer species, antler cycle was seasonal, but persistence of cycle-to-cycle antler growth well into adulthood is different from what occurs in most deer species.     

Do Antlers Honestly Advertise the Phenotypic Quality of Fallow Buck (Dama dama) in a Lekking Population?

Size and symmetry of secondary sexual traits are supposed to be honest signals of male phenotypic quality in vertebrates. Antler size and symmetry, male quality and mating success have not been fully demonstrated to be correlated in cervids. Such correlations can be particularly intriguing in the case of species adopting costly mating strategies, which imply territorial defence without feeding. In these cases, body condition appears to be crucial at the onset of the rut, and large and symmetrical antlers may be borne by successful males. For these reasons, during four consecutive years, we analysed growth rate, size and symmetry of 26 fallow bucks’ antlers in relation to individual mating strategy and success in a lekking population. Territorial (T) males, which gained higher mating success in the lek, showed a faster antler growth (about 10 g/d per antler) than non‐territorial (NT) males (3.6–5.2 g/d per antler) during the velvet period, and this was likely because of optimized foraging strategies. At the onset of the rut, when antler growth was completed, T males had larger antlers than NT males. Possibly because of worsened body conditions, NT males showed a pronounced antler directional asymmetry, while T males did not. However, no direct link between antler symmetry and mating success was found, thus confirming the ambiguous role of antler asymmetry as an indicator of fitness. The faster the antler growth, the larger its final size and the higher its beholder’s mating success. Our results confirmed that, like groaning and scent marking, antler size reflects social status and dominance in male fallow deer, and therefore represents an honest advertisement of phenotypic quality.     

Does fluctuating asymmetry of antlers in white-tailed deer (Odocoileus virginianus) follow patterns predicted for sexually selected traits?

Secondary sexual characters have been hypothesized to signal male quality and should demonstrate a negative relationship between the size of the trait and degree of fluctuating asymmetry because they are costly to produce. We collected morphometric and antler data from 439 white-tailed deer (Odocoileus virginianus) in Oklahoma, USA, in order to determine whether measures of antler asymmetry follow the patterns predicted for sexually selected characters. Relative fluctuating asymmetry was negatively related to antler size for all deer and within age groups up to five and a half years of age. We did not detect an association between asymmetry and antler size among deer that were six and a half years or older. When categorizing deer by antler size, we found that deer with small antlers (< or = 33rd percentile) had greater levels of relative asymmetry than deer with large antlers (< or = 67th percentile). The relative asymmetry of antlers was negatively related to age and was greatest in deer that were one and a half years old. Relative asymmetry was also negatively related to carcass mass, inside spread, skull length and body length. These data suggest that asymmetry in the antlers of white-tailed deer may be a reliable signal of quality and, as such, may be important in maintaining honesty in intrasexual advertisements during the breeding season.     

Effect of antiandrogen cyproterone acetate on the development of the antler cycle in Southern pudu (Pudu puda)

The antler cycle of pudu is similar to other cervids, but unlike most boreal deer, male Southern pudu (Pudu puda) exhibits two seasonal peaks of LH and testosterone. In that respect, pudu is similar to roe deer. Whereas the antler cycle in some deer species, such as roe deer or white-tailed deer, is very sensitive to variation of testosterone, in other cervids, such as fallow deer or reindeer, a blockade of androgens with cyproterone acetate (CA) has little or no effect on the timing of the antler casting. In order to test the sensitivity of pudu antlers to variations of androgens, CA (administered 2x weekly at 50 mg/buck) was injected intramuscularly for 3 weeks in 5 adult male pudu, starting February 19 (late summer). Four other males of similar age served as controls. The experiment was performed at the University of Concepcion, Chile, latitude 36.6 degreeS. Blood samples were taken once a week between January 19 and April 3. In CA-treated bucks, the antlers were cast approximately 3 weeks after the initiation of CA treatment and a new antler growth began almost immediately. The antlers reached about 5 cm in length, before ceasing to grow at the end of April, when they became mineralized and were subsequently polished. CA had no effect on the already declining levels of LH. Plasma levels of testosterone in controls increased from February 15, whereas in CA-treated bucks remained depresses until March 21. It is concluded that similarly to white-tailed deer, the antler cycle of Southern pudu is very sensitive to manipulation of androgen levels.     

Functional directional asymmetry in fallow deer (Dama dama) antlers

The right antlers of fallow deer are significantly more developed than the left antlers with respect to the lengths of the beam, trez tine and palm, as well as antler weight and number of points. The cross-section at the base is also more elliptical in the right antler. The size difference is correlated with the more intense use of right antlers in fighting, and with the greater breadth of the areas of insertion of the neck muscles in the skull's nuchal region.     

Revisiting the allometry of antlers among deer species: male–male sexual competition as a driver

The positive allometry between antlers and shoulder height reported for cervids has previously been interpreted as resulting from a high male‐male competition in large species that form large breeding groups. We aim at revisiting relative antler size variation among deer species by including more species (n = 31) and by testing both direct and indirect influences of different sexual selection proxies on the relative antler length using path analysis. The absence of direct effect of mating tactic on relative antler allometry indicates that the strength of fights does not differ among mating tactics. On the other hand, the main effect of breeding group size is revealed by polygyny. Highly polygynous species have relatively longer antlers than less polygynous ones but the difference in the relative effect of breeding group size on relative antler length is weak. Strong direct effect of breeding group size and indirect effect of mating tactic shaped the observed variation in the relative antler size among deer, suggesting that the amount of male‐male competition is the main evolutionary force of antler allometry in cervids.     

梅花鹿重组Galectin-1的表达及多克隆抗体的制备与鉴定

半乳糖凝集素-1（Galectin-1）是最先被报道的哺乳动物半乳糖凝集素,存在于多种组织和细胞内,参与细胞的粘附、增殖、凋亡和炎症反应等多种生理病理过程,并且与免疫系统的调节和肿瘤的发生发展密切相关。鹿茸是哺乳动物中罕见的能够周期性的脱落和再生的附属器官,作为研究哺乳动物器官再生的新模型受到关注。鹿茸再生是一个基于干细胞的过程,定位于角柄骨膜的干细胞是鹿茸再生的基础,Galectin-1在角柄骨膜细胞（pedicle periosteum cell, PPC）中高度表达,提示其在鹿茸再生中发挥着重要的作用。由于尚没有商用的鹿Galectin-1蛋白及其抗体,为进一步研究Galectin-1在鹿茸再生中的生物学功能,需要制备相应的蛋白和抗体,本实验将梅花鹿Galectin-1基因与pET28a连接,并将重组质粒pET28a-Galectin-1转入大肠杆菌（Escherichia coli）BL21(DE3)中诱导表达。用Ni-NTA Agarose亲和层析纯化融合蛋白,免疫兔子制备多克隆抗体。酶联免疫吸附（enzyme-linked immunosorbent assay, ELISA）法检测抗体效价、Western blot 检测抗体特异性、细胞免疫荧光检测Galectin-1在角柄骨膜细胞中的表达情况。结果表明,本实验成功诱导重组原核表达载体pET28a-Galectin-1在BL21(DE3)中表达,通过Ni纯化获得融合蛋白。ELISA结果显示,抗体效价达到1:64000,Western blot结果表明该抗体特异性良好,细胞免疫荧光显示Galectin-1在PPC全细胞中表达。本实验获得了纯化的鹿Galectin-1蛋白和特异性较好的多克隆抗体,为揭示Galectin-1在鹿茸再生调控中的作用提供了重要的实验材料。     

Antler growth and morphology in a feral sika deer (Cervus nippon) population in Killarney, Ireland

Antler growth and form was examined for a sample of 303 sika stags (Cervus nippon) culled over an eight-year period from a feral population in Killarney National Park, County Kerry, Ireland. Most antler measurements taken were highly correlated with each other and growth was complete after the sixth year. Few abnormalities were recorded and the degree of asymmetry in structure was less than previously reported for other sika populations. Variability in structure decreased with age and there was no effect of year of birth or cull on antler size for either adult or yearling stags. The growth pattern was similar to that of other populations except that the proportion of 'eight pointers' was low. An examination of antler damage was used to estimate fighting frequency across age classes. The results are discussed in relation to the genetic history of the herd and the use of antlers as weapons for intra-specific combat.