Rutting Period Research Articles

Male camel behavior and breeding management strategies: how to handle a camel bull during the breeding season?

The present article reviews male camel behavior and bre eding management strategies, providing an insight into the handling procedures and the most relevant welfare issues on these topics. Furthermore, it suggests some procedures for rearing, handling and collecting semen from camel bulls, based on results that have been achieved in the last twenty years and, recently, literature published with the aim of optimizing dromedary camel breeding. Camels are seasonal breeders and their breeding season (BS) is confined to the coolest winter months of the year; during the BS, also called “rutting period” or rut, males exhibit morphological, behavioral and endocrinological peculiarities. Short breeding season, low libido and high aggressiveness are still some of the major cause of economic loss, poor reproductive perfor mance and injuries, for camel breeding and industry. The application of ethology to approach, to train and to study camel bulls may be useful in the future to improve camel welfare and productive performances. Strong knowledge of animal learning and correct management procedure could be useful for camel technicians, owners, breeders, but also for veterinarians and others scientists.

The economics of scent marking with urine and feces in goitered gazelle (Gazella subgutturosa)

Apart from the purely physiological excretion function, many mammals use their own urine and feces as reliable, odoriferous signals to indicate territorial occupancy. Marking is especially important for many antelopes, as territoriality is linked to reproductive success in these species. Scent marking with excrement, though, imposes physiological constraints in the amounts of urine and feces they can produce for these acts. Some male antelopes have been found to be able to regulate the size of their fecal marks, increasing marking frequency and decreasing the volume per defecation deposit compared to that of females. In this paper, we investigate quantitative characteristics of urination-defecation acts in goitered gazelles (Gazella subgutturosa), such as excretion frequency and duration, and explain potential differences in urine and fecal marking behavior for goitered gazelles based on sex, age, season, and territorial status. Our study found that frequency of urination-defecation acts in adult males fluctuated significantly over seasons and was highest in males during the rut, while subadult males urinated-defecated more rarely and with longer acts of urination than adults. In contrast, females (both adult and subadult) urinated and defecated at the same rate without significant seasonal changes. During the rutting period, urination duration in adult males decreased significantly with the rate increasing but even then, urination duration was longer than in females; defecation duration, on the other hand, remained relatively stable in adult males over months compared to urination duration, irrespective of rate. This finding is contradictory to the “material (urine and feces) saving hypothesis” as found for male oribi (Ourebia ourebi). We also discovered that in contrast to females and non-territorial males, territorial goitered gazelle males intensively ate snow during the rut, likely to compensate for water loss during their vigorous urination marking activity. The stability in defecation duration in adult and subadult males, however, regardless of seasonal changes in rate, was difficult to explain.

Temporally dynamic habitat suitability predicts genetic relatedness among caribou.

Landscape heterogeneity plays a central role in shaping ecological and evolutionary processes. While species utilization of the landscape is usually viewed as constant within a year, the spatial distribution of individuals is likely to vary in time in relation to particular seasonal needs. Understanding temporal variation in landscape use and genetic connectivity has direct conservation implications. Here, we modelled the daily use of the landscape by caribou in Quebec and Labrador, Canada and tested its ability to explain the genetic relatedness among individuals. We assessed habitat selection using locations of collared individuals in migratory herds and static occurrences from sedentary groups. Connectivity models based on habitat use outperformed a baseline isolation-by-distance model in explaining genetic relatedness, suggesting that variations in landscape features such as snow, vegetation productivity and land use modulate connectivity among populations. Connectivity surfaces derived from habitat use were the best predictors of genetic relatedness. The relationship between connectivity surface and genetic relatedness varied in time and peaked during the rutting period. Landscape permeability in the period of mate searching is especially important to allow gene flow among populations. Our study highlights the importance of considering temporal variations in habitat selection for optimizing connectivity across heterogeneous landscape and counter habitat fragmentation.

Impact of interspecific relations between native red deer (Cervus elaphus) and introduced sika deer (Cervus nippon) on their rutting season in the Doupovské hory Mts.

The behaviour of sika and red deer during the rutting season is highly variable in relation to vocalization, habitat preference during the rut, and onset and termination of rutting. The red deer is a native species in Central Europe, but the areas where it lives in sympatry with the introduced sika deer have been increasing in the last three decades. Such situation can be found in the Doupovské hory Mts., where sika deer has been intensively spreading. Hybridization between the two species and changes in behaviour are the most important problems. In this study we prove the shift in the rutting period shown by both species. To evaluate the shift in the rutting season, we used a very extensive long-term data set on deer shot within the Military Training Area. These changes occur very slowly, however, and are very difficult to monitor and evaluate in the wild. Based on our results, the timing of the rutting season has converged at the mean rate of 0.62 day per year (rutting season starts later in the red deer and earlier in the sika deer).  

A one night stand? Reproductive excursions of female roe deer as a breeding dispersal tactic

Breeding dispersal, defined as the net movement between successive breeding sites, remains a poorly understood and seldom reported phenomenon in mammals, despite its importance for population dynamics and genetics. In large herbivores, females may be more mobile during the breeding season, undertaking short-term trips (excursions) outside their normal home range. If fertilisation occurs, leading to gene flow of the male genome, this behaviour could be considered a form of breeding dispersal from a genetic point of view. Here, we investigated ranging behaviour of 235 adult roe deer using intensive GPS monitoring in six populations across Europe within the EURODEER initiative. We show that excursions are common from June to August among females, with 41.8% (vs. 18.1% of males) making at least one excursion. Most individuals performed only one excursion per season and departure dates for females were concentrated in time, centred on the rutting period, suggesting a link with reproduction. The distance females travelled during excursions was significantly greater than the site-specific average diameter of a male home range, while travel speed decreased once they progressed beyond this diameter, indicating search behaviour or interaction with other male(s) outside the resident male's territory. Because adults are normally highly sedentary, the potential for mating with relatives is substantial; hence, we conclude that rut excursions could be an alternative tactic enabling females to avoid mating with a closely related male. To understand better the ultimate drivers at play, it will be crucial to explore the genetic causes and consequences of this behaviour.

Roaring function in male goitered gazelles

Most of the vocalizations of Antilopinae males are soft and usually only heard from a very close distance. The goitered gazelle is a rare exception to this rule, and during the rutting period territorial males of this species are among the noisiest antelopes. Rutting vocalization is such an essential part of the rutting behavior in goitered gazelle that adult males have a hypertrophic larynx, the muscle tissues of which increase considerably in size during the rut. We were interested in the frequency and variance with which male goitered gazelles emit their calls depending on an animal's age, reproductive status and time of the year in order to understand the main function of the rutting vocalizations. We found that roaring was mostly related to courting displays, while vocalizations during aggressive displays were less frequent in male–male interactions. Acoustic signals likely enhance courtship displays and also may aid in accelerating female ovulation, promoting synchronization of breeding cycles during the mating and birthing periods, which last only several days for most of the females in our population. We discuss the potential benefits of such behaviors and compare it to other species living in similarly extreme environments.

Demographic characteristics, seasonal range and habitat topography of Balkan chamois population in its southernmost limit of its distribution (Giona mountain, Greece)

The annual range of Balkan chamois (Rupicapra rupicapra balcanica) in Giona mountain was found to be 5502 ha, with a low population density (2 individuals/100 ha). Seasonal range patterns varied significantly, with a minimum extent in summer and a maximum in winter (30% and 79% of the annual range, respectively). Summer stress and the rutting period might be associated with the observed aggregated distributions during the summer and autumn (core areas of 28% and 22% of seasonal ranges, respectively, defined after the Fixed Kernel Density Estimator). Chamois were found to use significantly lower altitude habitats in winter (1212 m) than in summer (2223 m), and significantly steeper slopes in winter (35°); aspect was not found to have a significant effect on habitat use. Population structure consisted of kids (21%), yearlings (8%), females (35%) and males (36%). Conservation management for the species should consider poaching, livestock competition and global warming.

At home in a new range: wild red deer in south-eastern Queensland

Context Wild deer are increasing worldwide and, in Australia, prompting land managers to review management strategies. Management activities may be ineffective without a sound understanding of the ecology of the species. No peer-reviewed research has been published for wild red deer in Australia, where they have been introduced. Aims To help land managers gain an understanding of some movement parameters of introduced wild red deer out of their natural range. Methods GPS collars were used to obtain movement rates (m h–1), annual home range using three estimators and seasonal home range using the Local Convex Hull estimator. Key findings Deer at our study site displayed typical crepuscular movements. However, the lack of elevated activity for stags in summer varies greatly to reports from overseas. The annual home range of hinds was much smaller than that of stags. Large differences for seasonal home ranges from the same deer for two winters suggest that seasonal conditions may exert a large influence on the size of home ranges. The home ranges of deer at our study site were comparable with the largest reported in European studies, but the relationship between deer density and home-range area was markedly different. Conclusions It appears that Australian wild red deer behave differently from their European conspecifics for several important movement parameters. Wild stags did not display the high levels of movement activity in summer, like those in Europe, and the home-range areas of our deer were very large for the high densities we encountered compared with overseas reports. Implications Targeted management of hinds may prove beneficial as hinds had a much smaller and continuous home range than stags. If managers want to target stags, there is only a short rut period when they continually associate with hinds and that may be the most efficacious time for control. Additionally, future research may need to explore the link between home range and deer density, and the effect of variation in rainfall on home range and movement of wild red deer which may influence management activities more than do the regular seasonal patterns found in Europe.

The energy-maintenance strategy of goitered gazelles Gazella subgutturosa during rut

In many polygynous ruminant species, males decrease their food intake considerably during the rut. To explain this phenomenon of rut-reduced hypophagia, two main hypotheses, the Foraging-Constraint Hypothesis and Energy-Saving Hypothesis, have been proposed. In our research, we assessed the behavioral strategy of goitered gazelles (Gazella subgutturosa) through the rutting period. According to our findings, male goitered gazelles spent less time feeding during the rut compared to pre- and post-rut feeding times, but then maximized their energy intake during the rutting season when they were not engaged in rut-related behaviors. Females, in contrast, did not change their time budgets across the different stages of the rut. Therefore, rut-induced hypophagia is mainly arising from the constraints of rut-related behaviors for male goitered gazelles, so that the Foraging-Constraint Hypothesis better explains their strategy during rut.

Consequences of snowy winters on male mating strategies and reproduction in a mountain ungulate

Alternative mating tactics (AMTs) are intrasexual variants in mating behaviour of several species ranging from arthropods to mammals. Male AMTs coexist between and within populations. In particular, male ungulates rarely adopt just one tactic throughout their lifetime. Tactics commonly change according to internal factors (age, body size, condition) and external conditions (weather, resources, predation, animal density). However, the influence of weather has not yet been investigated in upper vertebrates. Such influence may be relevant in species whose rutting period occurs late in fall or in winter, when environmental conditions and the snow cover in particular may vary considerably. We detected two AMTs in Alpine ibex (Capra ibex) males: older and full-grown males mainly adopted the tending tactic, while younger males usually pursued an alternative one (coursing tactic). Weather was found to influence the use of AMTs by males: in snowy mating seasons, the coursing tactic was no longer used due to difficulties in moving through deep snow. In snowy rutting periods, males appeared to delay or even avoid mating activities and a decrease of births was reported in the second part of the following birth season. Snow cover may have a negative effect on population dynamics by reducing the recruitment and on population genetic variability, as a consequence of poorer mating opportunities. Studies on factors affecting mating behaviour and leading to a reduced availability of mates and a decrease in female productivity are especially relevant in species, like Alpine ibex, whose genetic variability is low.

Excursion behaviour of female roe deer may depend on density

The excursion behaviour of roe does was studied for two years in a low density population (ca. 6.5 ind./100ha), in an Apennine-continental forest of Southern Italy, through satellite radiotracking. During the rutting period, our radiotagged does (N=6) moved well outside their summer ranges, with an average exploration area eight times greater than summer ranges. The median duration of excursions was 51h (range: 10–99h). One female stayed away for a total of 11 days. In order further to understand this behaviour, we reviewed all studies (N=6) dealing with excursion behaviour of roe does and carried out in areas where population density was assessed through the same method (i.e. drive counts). Out of five ecological parameters included in the analysis, excursion behaviour of roe does was found significantly and negatively associated only to population density: when density was low, the proportion of roaming does increased, probably because of the lower availability of “free” bucks during the short time of female oestrous.

Social organization in goitered gazelle (Gazella subgutturosa Güldenstaedt 1780)

The population structure of goitered gazelles was investigated in Kazakhstan over several years. We found that the social organization of goitered gazelle changed over months mostly because of their birthing and rutting behaviour, and seasonal migrations. Female groups were smallest and solitary females were the most numerous during parturition in May and these groups were largest during rutting season in November–December. In contrast, male groups were smallest and solitary males were the most numerous during the rutting period, while during the rest of the year they formed considerably larger groups although male singletons were always common. Mixed-sex groups were typical for spring and autumn migration periods in March–April and in October. The month also influenced the population structure with larger groups more common during cold months and smaller groups frequently observed during hot months, but such impact was not as distinctive as in the case of biological events (birthing, mating and migration). Despite living in northern latitudes, goitered gazelles have a social organisation that is comparable with other gazelle species.

Variation in reproduction of a temperate deer, the southern pudu (Pudu puda)

Pudu (Pudu puda), occurring in the southern cone of Latin America, has been classified as vulnerable by the International Union for Conservation of Nature (IUCN), yet little is known about this animal in the wild, with most knowledge on the breeding behaviour coming from captive animals. For this second-smallest deer in the world, delayed implantation has been suggested to explain the two peaks in the annual cycle of male sexual hormones on the basis of the accepted tenet that the breeding period occurs only once a year, between March and June. However, in the present study, birth dates from fawns born at the Los Canelos semi-captive breeding centre in Chile and male courting behaviour revealed the possibility of two rutting periods: autumn and spring. To our knowledge, this is the first time that late-fall births (May through early June for 17% of fawns in the study population) have been recorded for the southern pudu; two of these four births were conceived by females in the wild. From zoo and captive-animal birth records (n = 97), only three fawns were born in the fall. For all births combined (n = 121), 77% occurred in spring. The roe deer (Capreolus capreolus) and Pere David deer (Elaphurus davidianus) have been considered the only two temperate cervids in which sexual activity is initiated by increasing daylength and which breed in early summer. Yet, the present results indicate a similar response from the southern pudu when under a wild or semi-captive environment, with breeding taking place in spring. These results suggest that this species may either have two reproductive periods per year or retains the capacity to be a breeder for a much more extended period of time than documented by earlier studies. Pudu, like other temperate deer, is responsive to photoperiod for timing its breeding period, but may further optimise its production of offspring by also responding to other environmental cues such as seasonal variation in food supply when climatic conditions are favourable.

Contrasting Life Histories in Neighbouring Populations of a Large Mammal

BackgroundA fundamental life history question is how individuals should allocate resources to reproduction optimally over time (reproductive allocation). The reproductive restraint hypothesis predicts that reproductive effort (RE; the allocation of resources to current reproduction) should peak at prime-age, whilst the terminal investment hypothesis predicts that individuals should continue to invest more resources in reproduction throughout life, owing to an ever-decreasing residual reproductive value. There is evidence supporting both hypotheses in the scientific literature.Methodology/Principal FindingsWe used an uncommonly large, 38 year dataset on Alpine chamois (Rupicapra rupicapra) shot at various times during the rutting period to test these two hypotheses. We assumed that body mass loss in rutting males was strongly related to RE and, using a process-based approach, modelled how male relative mass loss rates varied with age. For different regions of our study area, we provide evidence consistent with different hypotheses for reproductive allocation. In sites where RE declined in older age, this appears to be strongly linked to declining body condition in old males. In this species, terminal investment may only occur in areas with lower rates of body mass senescence.Conclusions/SignificanceOur results show that patterns of reproductive allocation may be more plastic than previously thought. It appears that there is a continuum from downturns in RE at old age to terminal investment that can be manifest, even across adjacent populations. Our work identifies uncertainty in the relationship between reproductive restraint and a lack of competitive ability in older life (driven by body mass senescence); both could explain a decline in RE in old age and may be hard to disentangle in empirical data. We discuss a number of environmental and anthropogenic factors which could influence reproductive life histories, underlining that life history patterns should not be generalised across different populations.

Seasonal changes in group size and composition of Arabian sand gazelle Gazella subgutturosa marica Thomas, 1897 during a period of drought in central western Saudi Arabia

Abstract Group size variations of the Arabian sand gazelle Gazella subgutturosa marica were studied during a period of drought at the Mahazat as-Sayd Protected Area in central western Saudi Arabia. Significant differences in median group sizes were observed between all seasons except summer. Single animals were observed mainly during summer while group sizes exceeding 10 individuals were observed mainly during winter. Solitary male and female groups were typically observed during winter and mixed groups mainly during the autumn rutting period. Most mixed groups were two to four times larger during winter than summer. The adult sex ratio (male: female) for all seasons combined was in parity and highest during autumn (1:1.23), probably as a result of prolonged drought conditions. The variability in group structure related to environmental conditions may be one factor permitting G. s. marica to adapt to hyper-arid habitats and climatic regimes in central western Saudi Arabia. The value of continuous monitoring of the gazelle population is emphasised for this drought prone region.

Relative Effect of Food Supplementation and Natural Resources on Female Red Deer Distribution in a Mediterranean Ecosystem

ABSTRACT Supplementary feeding is a widespread game management practice in several red deer (Cervus elaphus) populations, with important potential consequences on the biology of this species. In Mediterranean ecosystems food supplementation occurs in the rutting period, when it may change mating system characteristics. We studied the role of food supplementation relative to natural resources in the spatial distribution, aggregation, and mean harem size of females in Iberian red deer (Cervus elaphus hispanicus) during the rut. We studied 30 red deer populations of southwestern Spain, 63% of which experienced supplementary feeding. Using multivariate spatial analyses we found that food supplementation affected distribution of females in 95% of the populations in which it occurred. Green meadows present during the mating season acted as an important natural resource influencing female distribution. Additionally, the level of female aggregation and mean harem size were significantly higher in those populations in which food supplementation determined female distribution than in populations in which female distribution did not depend on supplementary feeding. Because female aggregation and mean harem size are key elements in sexual selection, supplementary feeding may constitute an important anthropogenic element with potential evolutionary implications for populations of Iberian red deer.

Effects of a synthetic gonadotrophin-releasing hormone agonist, leuprolide, on rut-associated events in male red deer

This study examined the effectiveness of leuprolide, a gonadotrophin-releasing hormone agonist, in suppressing rut-associated events in farmed male red deer. In mid-January (~6 weeks before the rut period in the southern hemisphere) adult red deer (Cervus elaphus scoticus) stags that had been allocated to three groups (n = 10 per group) received leuprolide, administered subcutaneously in a 90-day release formulation, at zero (control), low (22.5 mg) or high (45 mg) doses. Following treatment with leuprolide there was evidence of suppression of mean plasma luteinising hormone concentration that was significant (P < 0.05) at 9 weeks. Mean plasma testosterone concentration of all three groups rose following treatment, then declined prematurely in the low- and high-dose leuprolide-treated groups, so that it was significantly (P < 0.05) suppressed (0.66 ± 0.29 and 2.0 ± 0.88 ng mL–1, low and high dose respectively) in early April when the peak value (9.0 ± 1.94 ng mL–1) was recorded from control stags. A reduction in mean liveweight occurred in all three groups through February–April and this did not differ among treatments. However, a corresponding reduction in mean body condition score was greater in the control stags (P < 0.05). There was little effect of leuprolide treatment on aggressive behaviours, but it lowered roaring frequency in the latter period of the rut. The results indicate that this gonadotrophin-releasing hormone agonist has potential for application in the deer farming industry to suppress undesirable effects of the rut.

Habitat selection by forest-dwelling caribou in managed boreal forest of eastern Canada: Evidence of a landscape configuration effect

Habitat alteration caused by forest harvesting seems to contribute to the decline of forest-dwelling caribou, an ecotype of woodland caribou ( Rangifer tarandus caribou) inhabiting the boreal ecosystem. To serve as basework to the establishment of conservation measures for the species, we have studied the hierarchical habitat selection of forest-dwelling caribou in a boreal landscape of Québec strongly impacted by logging. Fifteen females were surveyed by GPS telemetry between April 2004 and March 2006. Home ranges showed a high proportion of 90–120 year-old forests, a low proportion of regenerating forests (20–40 years old) and a tendency to include a greater proportion of 6–20 year-old clearcuts in relation to their availability in the study area. At the home range scale, selection patterns differed between periods, possibly reflecting specific requirements linked to caribou life cycle. Caribou selected open lichen woodlands throughout the year while mature closed forests (≥50 years) were selected uniquely during summer. The 6–20 year-old clearcuts were avoided during calving, in summer and during the rutting period but were selected during spring. Our results indicate that mature forest and open lichen woodlands are highly selected forest cover types by caribou at both spatial scales. Although clearcuts were generally avoided at the home range scale, such avoidance was not observed at the larger scale, the search for 90–120 year-old forests being hampered by a uniform distribution of clearcuts. An a posteriori landscape analysis highlighted the spatial association between 6–20 year-old clearcuts and 90–120 year-old forests, an association that can be explained by the current regulations used in Québec. Our results underline the importance of pursuing research concerning the impact of such an exploitation regime on the long-term maintenance of the forest caribou in the boreal landscape.

Ranging behaviour and excursions of female roe deer during the rut

Anecdotal evidence has suggested that, during the rutting period, female roe deer may undertake short excursions, outside of their normal home range, possibly to mate with a reproductive partner. To address this question, we analysed the ranging behaviour of 27 female roe deer Capreolus capreolus, equipped with GPS collars, inhabiting a fragmented landscape in France. We compared female movements during the rutting period with a non-rutting period over two summers using a recently published approach. Search intensity and home range size were significantly greater during the rutting period. The difference in home range size between the two periods was significantly greater in 2006 compared to 2005 and in open compared to closed habitat. We were not able to identify any influence of body mass on the difference in ranging behaviour between the two periods. Visual analysis of movement trajectories for 11 females revealed that 5 (45%) performed an excursion for a duration of a few hours to several days. We speculatively suggest that female rut excursions provide an opportunity for active mate choice in roe deer, where males are territorial, although we cannot rule out the alternative explanation that these movements are a means to avoid male harassment.

Seasonality and the melatonin signal in relation to age as correlated to the sexual cycle of the one-humped male camel (Camelus dromedarius)

Heparinized blood samples were taken from male immature and mature camels of the Sha'alah breed, housed at the University Animal farm, during the rutting and non-rutting period. Other blood samples were also collected from camels slaughtered at defined seasons (summer, autumn, winter and spring) and from the Buraydah slaughter-house. In addition, specimens from the testes were also taken to confirm the difference between the immature and the mature animals during the non-rutting and rutting seasons. The plasma obtained from the collected blood samples was used for estimation of the following hormones, Melatonin (MLT), Follicle Stimulating Hormone (FSH), Leutinizing Hormone (LH), Testosterone and Prolactin (PRL) using the radioimmunoassay technique. Specimens of testes tissue were fixed in calcium formol, processed for histological examination using standard procedures and stained with H&E. The results clearly differentiated the samples as immature and mature during the non-rutting and rutting seasons. Commercially available human radioimmunoassay (RIA) kits for MLT, FSH, LH, testosterone and PRL were adapted for quantitation of these hormones in serum from the one-humped camel (Camelus dromedarius). Serum samples from 40 camels were assayed in order to determine possible differences between various groups in the concentrations of MLT, FSH, LH, testosterone and PRL in these animals. Among the camels, serum concentrations of melatonin, FSH, LH, testosterone and prolactin reflected age and seasonal differences. Immature camels had overall significantly lower levels in MLT, FSH, LH, testosterone and PRL. Mean FSH and LH levels from confirmed non-rutting (sexually inactive) camels were 0.22 ± 0.08 and 0.37 ± 0.18 ng/mL, respectively. Although rutting (sexually active) camels had higher FSH and LH levels, the differences were not statistically significant (P less than 0.07). Our observations indicate that these RIAs can reliably detect serum MLT, FSH, LH, testosterone and PLT from camels and represent the first quantitation of melatonin in Camilidae in correlation with FSH, LH, testosterone and prolactin.