Inter-individual Distances Research Articles

Application of a wearable GPS unit for examining interindividual distances in a herd of Thoroughbred dams and their foals.

ABSTRACTGlobal positioning system (GPS) units are now lightweight and compact. They have proven useful for analyzing the behavioral characteristics of horses in pastures. Because the GPS records data in latitude and longitude, it may be feasible to calculate the distance between GPS units. The present study aimed to confirm the applicability of GPS units in behavioral studies on horses. For this, we analyzed the accuracy of the distances calculated from GPS units using Hubeny’s distance formula and of the monthly changes in interindividual distances obtained from GPS units worn by Thoroughbred dams and their foals in a pasture until weaning. The calculated inter-GPS distances were highly accurate. The regression line was linear, and the squared correlation coefficient (r2) was 0.9998. During the first month of age, the interindividual dam–dam and foal–foal distances were significantly greater than the dam–foal distance. During the second month of age, the dam–foal distance increased once and gradually decreased up to the fifth month of age. During the sixth month of age, the dam–foal distance was significantly greater than the foal–foal distance. The GPS distances calculated using Hubeny’s distance formula were useful for analyzing changes in interindividual distances in a herd of Thoroughbred dams and their foals. Most likely, calculation of the distance between GPS units worn on equine head collars is likely to become a very useful tool as an objective index for quantifying equine behavioral observations.

Conservation genetics of European bees: new insights from the continental scale

Population connectivity is an important source of information for planning conservation strategy. The degree of connectivity implies using alternative conservation prioritizations based on the appropriate spatial scale for management units. In species with low population connectivity, it is important to preserve local populations in order to maintain the species throughout its range. In contrast, species with high connectivity require extensive management aiming at preserving gene flow through the entire species range. Here we examine at the continental scale the relationship between inter-population/inter-individual genetic and geographical distances to study the isolation-by-distance (IBD) pattern within the European range of nine wild bee species. We then assess the suitability of multi-local or extensive conservation to ensure their long-term survival. Results based on inter-population differences show only two out of nine species with significant IBD. European bee populations seem quite connected when their IBD is compared to IBD of other phyla. However, our results based on inter-individual distances show that eight out of nine species display significant IBD. These different results are presumably a consequence of potential limitations of the inter-population approach. Therefore, we speculate that the inter-population approach could result in inaccurate IBD estimations. This approach should therefore be replaced by the inter-individual approach in order to provide strong supported conservation guidelines. We support multi-local conservation programs based on our analysis of inter-individual distances.

A Concurrent Longitudinal Survey of the Mucosa-Associated Colonic Bacterial Microbiota and Stool Microbiota in Healthy Subjects Shows Preservation of Individual Differences over Time

Introduction: While limited longitudinal studies have assessed the stability of the gut microbiota in fecal samples, there are no published studies to date that have examined the stability of the mucosa-associated microbiota. In this study, we aimed to concurrently characterize the variability in the gut microbiota in mucosal biopsies and stool samples of healthy subjects over a 9 month period. Methods: Healthy control subjects (n=9) were recruited from the community and underwent 4 unprepped flexible sigmoidoscopies at 0, 3, 6, and 9 months. Biopsies were taken of the colonic mucosa during the sigmoidoscopy and stool samples were collected at the same visit. Microbiota was characterized by sequencing of the 16S rDNA on a 454 Roche Titanium platform. Obtained sequences were filtered for quality/chimeras, and were analyzed using Qiime. Unifrac distances were calculated between the samples of the same subject (intra-individual distances), and were compared to the distances from the samples of other subjects (inter-individual distances). Results: Bacterial composition remained relatively stable over time in individual subjects over 9 months; and inter-individual Unifrac distances were higher than intra-individual ones ( 0.714 ± 0.058 vs.0.610 ± 0.085 respectively, p=0.001) for the entire sample set. This significant difference between inter-individual and intra-individual Unifrac distances was preserved for both colonic biopsy samples and for stool samples (p=0.0001 for both). When intra-individual Unifrac distances between stool samples were compared to that of biopsy samples, there was no observed difference between the sample types (0.586 ± 0.628 vs. 0.579 ± 0.076 respectively, p=0.384), suggesting that there is a similar degree of variability in the longitudinal stool samples and the longitudinal biopsy samples of the same individual. However, higher inter-individual Unifrac distances were noted in longitudinal stool samples compared to longitudinal biopsy samples (0.713 ± 0.057 vs. 0.691 ± 0.052 respectively, p=0.0001), suggesting that there is a slightly lower variability within longitudinal biopsy samples of different individuals. Conclusion: Inter-individual variation in the bacterial microbiome is preserved in longitudinal colonic biopsy samples. Time and sampling related variability in the mucosa-associated colonic bacterial microbiome in healthy individuals is not large enough to supercede inter-individual differences.

Effects of post-hatch brooding temperature on broiler behavior, welfare, and growth

An elevated brooding temperature during the first wk post hatch of broilers may potentially increase activity levels and reduce welfare problems in terms of non- and slow-starters, lameness, and contact dermatitis. The effects of an elevated brooding temperature the first 7 d post hatch on behavior, welfare, and growth of Ross 308 broilers were investigated. Groups of 28 broilers (14 males and 14 females) were distributed in a balanced way according to their hatching weight (below or above mean), the age of parent breeders (28 or 50 wk of age), and initial brooding temperature (normal 33°C; warm: 37°C) resulting in 8 different treatment groups. Behavioral data were collected on d zero to 6 of age, data on body weight on d zero, 7, 21, and 34 of age, and data on gait and contact dermatitis on d 21 and 34 of age. An elevated brooding temperature resulted in increased body temperature of broilers 5 h after placement (39.9 ± 0.04°C vs. 39.1 ± 0.04°C; P < 0.0001) whereas no difference was found 24 h after placement (P = 0.35). Broilers reared with elevated brooding temperature initiated feeding and drinking earlier, apart from broilers with low hatching weight from old parent breeders (P < 0.0001). They also showed higher activity levels from d one to 6 of age (P < 0.0001) and a higher inter-individual distance at d zero and one of age (P < 0.0001). Broilers with a high hatching weight reared at normal brooding temperature had a higher prevalence of hock burns at d 34 of age (P = 0.001). Broilers reared at elevated brooding temperature had lower body weight at d 7 of age (P < 0.0001); however, no difference appeared from d 21 of age (P = 0.58). No effect of brooding temperature was found on body weight uniformity (P = 0.81). In conclusion, the welfare of broilers may be improved from an elevated brooding temperature the first 7 d post hatch without affecting body weight uniformity and final body weight.

Variations in within-group inter-individual distances between birth- and non-birth seasons in wild female patas monkeys.

Individual spatial positioning plays an important role in mediating the costs and benefits of group living, and thus shapes different aspects of animal social systems including group structure and cohesiveness. I aimed to quantify variation in individual spacing behavior and its correlates in a group of wild patas monkeys (Erythrocebus patas) living in north Cameroon. I collected data on inter-individual distances during group scans when following subject females. Individuals had longer inter-individual distances during the non-birth season than during the birth season. Dominance relationships had little effect on inter-individual distances between females during both the non-birth and birth seasons. The results suggest that group cohesion was higher during the birth season than the non-birth season. Thus I conclude that higher group cohesion during the birth season may reduce the predation risk of infants.

Offspring loss after male change in wild siamangs: the importance of abrupt weaning and male care.

Infanticide by males is assumed to promote permanent male-female associations, although its importance for social monogamy is still debated. We examined the consequences of male membership change in the largest socially monogamous primate, the siamang (Symphalangus syndactylus), a species that also forms polyandrous groups and where males may provide offspring care. We examine (a) the potential risk of infanticide by documenting changes in female-offspring relationships following male change, expecting abrupt weaning; and (b) the potential importance of male care and polyandry for offspring survival. We witnessed four male changes at Way Canguk Field Station (Indonesia) in groups where the youngest offspring was estimated to be about 2years of age. We quantified aspects of mother-offspring relationships (interindividual distance, body contact, and nipple contact) and estimated the proportion of time being carried during travel (August 2007-April 2009). In the two groups into which new males immigrated, offspring were weaned abruptly, suggesting infanticide by males as a potential risk. Even though no attacks on infants by males were witnessed, both infants disappeared shortly after the male change. Another infant disappeared after its main carrier (a male) emigrated. Conversely, in a group where the resident subordinate male replaced the dominant male, the offspring experienced no change in care and survived the transition. These findings suggest that male immigration in hylobatids increases mortality risk for infants, emphasize the importance of offspring care, and cast doubts on prior classifications of 2-year-old siamangs as independently traveling individuals.

Differences in behaviour of the nilgai (Boselaphus tragocamelus) during foraging in forest versus in agricultural land

Abstract:The nilgai (Boselaphus tragocamelus) is a widespread species in India that forages in forest as well as on agricultural lands. In Tadoba-Andhari Tiger Reserve, India, it typically takes to crop-raiding at night, while it rests and forages in forest during the daytime. We studied changes in herding and vigilance behaviour during foraging in forest versus in agricultural lands and monsoon versus post-monsoon in the years 2012–2015. We recorded number of individuals (herd size), sex-age composition and number of individuals per unit area of herd's spread (compactness) for every herd under observation using instantaneous scan sampling in forest (176 herds) and farms (321 herds), while spatial trends in herd size on agricultural lands were studied using transect sampling at night. Vigilance behaviour was studied using focal-animal sampling in forest (n = 91) and farms (n = 52) by choosing a single individual per herd under 15 min of observation. Herd sizes were significantly larger in forest (monsoon, median = 3, interquartile range (IQR) = 2–6, post-monsoon, median = 5, IQR = 3–8) than on farms adjacent to forest (monsoon = 3, IQR = 1–5, post-monsoon = 4, IQR = 2–5) and further decreased non-linearly with distance from the forest edge. Herds were more compact, i.e. with smaller inter-individual distance in forests than on farms. Crop-raiding was found to be female-biased, and adult males as well as newborn calves were observed on agricultural lands significantly less frequently. The median vigilance frequency was significantly higher on farms (1.4 min−1) as compared with forests (0.205 min−1) but the median unit scan duration was significantly less in farms (6 s) compared with forest (60 s). The observed differences are likely to be due to difference in the nature of risk faced in the two habitats. In forest, detection of ambush predators such as tigers that occur at a low density, requires careful watch and larger herds increase the chances of detection. In contrast, detection of guarding farmers on agricultural lands who are present at a higher density and make their presence conspicuous to drive away crop raiders would need a glance of smaller time duration. As crop-raiding occurs at night, moonlight is likely to affect the frequency of crop-raiding but we did not find evidence for any deterrent effect of moonlight on the frequency of crop-raiding. The data suggest that the nilgai exhibits substantial behavioural plasticity in response to different nature and levels of risks faced in the two habitats.

Proof of principle: the adaptive geometry of social foragers

The spatial configuration of a group of animals should reflect the ability of its members to respond to environmental contingencies. Under predation risk, the optimal position for an individual in a stationary group is at the group's centre. The resulting group geometry is circular, with individual placement determined by competitive ability. Where it compromises efficient foraging, a long-standing question has been whether this topology can deform adaptively in response to the local distribution of resources. Here we show that the shape described by a group of foraging chacma baboons, Papio hamadryas ursinus , changes in response to habitat structure and that this promotes foraging efficiency while conserving the predation-risk-related distribution of group members. Adult baboons improve unimpeded access to the small, dispersed food items found in grassland by adjusting both their interindividual distances and their relative positions along the line of movement in order to forage in rank formation. Dominant animals occupy the centre of the group and do so regardless of its geometry. Our results demonstrate that spatially explicit data can address emergent group level properties directly. This global approach complements analyses of individual action and can help direct the search for potential local rules of interaction.

Intracemetery biological variation at the fort ancient sunwatch village.

We investigate intracemetery biological variation at the Fort Ancient SunWatch village (800-500 BP.) to test the hypothesis that the SunWatch population consisted of spatially structured biologically differentiated kin groups consisting of distinct local Late Woodland and non-local Mississippian biological populations. The SunWatch sample contains 166 individuals: 63 adults and 103 subadults. We analyze intracemetery biological variation using two feature sets: the buccolingual diameters of the polar teeth in the permanent (n = 37) and deciduous (n = 26) dentitions. We apply matrix correlation models to biodistance and grave distance matrices in both data sets, evaluate burial outliers and individuals exhibiting a rare dental feature with interindividual biological distances, and evaluate potential cultural subgroups with Mahalanobis' distance. Matrix correlation analyses for both feature sets as well as interindividual and subgroup distances indicate the SunWatch village cemetery was kin structured, contained a single primary biological population, and also contained a small number of non-local individuals most of whom were from closely related populations. We thus reject the hypothesis that the SunWatch population consisted of biologically distinct Late Woodland and Mississippian biological populations. Although SunWatch village exhibited cultural attributes characteristic of both local Late Woodland and non-local Mississippian groups, biologically the village was composed of one primary population. The lack of evidence for marked biological differentiation in the SunWatch village area at about 800-500 BP. suggests diffusion and acculturation may account for Mississippian cultural characteristics in southwestern Ohio Fort Ancient villages. If gene flow or migrations from biologically distinct Mississippian populations into southwestern Ohio occurred, either or both likely occurred well before 800 BP. This would have allowed the process of admixture time to produce a relatively homogeneous, nondifferentiated population. The latter alternative is consistent with the appearance in southwestern Ohio of non-local individuals at one site linked to surrounding Mississippian regions at about 950 BP. Am J Phys Anthropol 160:719-728, 2016. © 2016 Wiley Periodicals, Inc.

Temperature modifies activity, inter-individual relationships and group structure in a fish.

A host of abiotic factors modify fish social behavior. However, few studies have characterized the effects of temperature on behavior. In this study, brown trout Salmo trutta fry were reared at 5 different temperatures (4°C, 6°C, 8°C, 10°C, and 12°C). In order to characterize group structure, 3 behavioral parameters were investigated: group social structure (based on inter-individual distances), inter-individual relationships (based on physical contacts), and individual activity. These behavioral parameters were studied at the emergence stage, which corresponds to a switch from a social gregarious life in the gravel to a solitary one in the water column. Data analysis showed that the inter-individual distances increased with increasing temperature, particularly the nearest neighbor distance. The mean number of physical contacts between fry increased at both low and high temperatures. At high temperatures, most fry moved apart from each other after a physical contact. Swimming activity decreased at both the lower and upper temperatures (18% of activity at 4°C, 38% at 8°C, and 12% at 12°C). This study showed that temperature modifies brown trout fry activity, inter-individual relationships, and social behavior, which all affect group cohesion before emergence and can influence their survival and dispersal.

Analysis of Post-agonism Reconciliation in a Captive Group of the Wedge-Capped Capuchin Monkey, Cebus olivaceus: a Pilot Study.

Agonism was often associated to an increase in inter-individual distances in social individuals; however, many evidences indicate that individuals affiliate after a dispute ( “reconciliate”). The post-agonism behavior of individuals in a captive troop of the wedge-capped capuchin monkey was described and conciliatory tendency (CT) was estimated by using the PC-MC (Post-Conflict – Matched Control) method; here PA-MC (Post-Agonism – Matched-Control). Males initiated more agonistic interactions toward females than to other males while females avoided initiating them toward males. Interestingly, females were more prone to initiate reconciliation than males, both toward males (CT: 0.20-0.42) and toward other females (CT: 0.24-0.25). Overall, the CT in the group ranged from 0.127 to 0.198. We compared our results with those from other capuchins and propose that reconciliation may not be fundamental in maintaining social cohesion in Cebidae; nonetheless, due to our small sample, this is a preliminary conclusion.

Effect of available space and previous contact in the social integration of Saint Croix and Suffolk ewes.

Reproduction in tropical sheep is not affected by season, whereas the reproductive cycle of temperate-climate breeds such as Suffolk depends on the photoperiod. Close contact with tropical ewes during the anestrous period might induce Suffolk ewes to cycle, making the use of artificial light or hormonal treatments unnecessary. However, the integration of both breeds within the social group would be necessary to trigger this effect, and so the aim of the experiment was to determine the speed of integration of 2 groups of Saint Croix and Suffolk ewes into a single flock, according to space allowance and previous experience. For this, 6 groups of 10 ewes (half from each breed) from both breeds, housed at 2 or 4 m/ewe (3 groups/treatment) and with or without previous contact with the other breed, were monitored for 3 d. Each observation day, the behavior, movement, and use of space of ewes were collected during 10 min at 1-h intervals between 0900 and 1400 h. Generalized linear mixed models were used to test the effects of breed, space allowance, and previous experience on behavior, movement, and use of space. Net distances, interbreed farthest neighbor distance, mean interbreed distance, and walking frequencies were greater at 4 m/ewe ( < 0.05). Intrabreed nearest neighbor, mean intrabreed neighbor, and interbreed nearest neighbor distances and minimum convex polygons at 4 m/ewe were greatest for Saint Croix ewes, whereas the opposite was found for lying down ( < 0.05). Experienced ewes showed larger intrabreed nearest neighbor distances, minimum convex polygons, and home range overlapping ( < 0.05). Experienced ewes at 4 m/ewe showed longest total distances and step lengths and greatest movement activity ( < 0.05). Experienced ewes walked longer total distances during Day 1 and 2 ( < 0.05). Lying down frequency was greater for Day 3 than Day 1 ( < 0.05), and Suffolk ewes kept longer interindividual distances during Day 1 ( < 0.05). After 3 d of cohabitation, Suffolk and Saint Croix ewes did not fully integrate into a cohesive flock, with each breed displaying specific behavioral patterns. Decreasing space allowance and previous experience resulted in limited benefits for the successful group cohesion. Longer cohabitation periods might result in complete integration, although practical implementation might be difficult.

Spatial requirements of poultry assessed by using a colour-contrast method (KobaPlan)

Sufficient floor space is a fundamental precondition for poultry to perform normal behavioural patterns. To calculate and determine stocking densities, it is essential to know the absolute minimum surface area required by any given animal (body space). Additional space is required for characteristic behaviours (behavioural space) and for adequate inter-individual distances, group sizes and room to perform social interactions have to be taken into account.To calculate body space, planimetric measurements were carried out by the colour contrast method “KobaPlan” in various poultry species in standing and sitting positions and at a number of different ages. They included laying hens (Lohmann brown (LB), Lohmann selected Leghorn (LSL)), broiler breeders (Ross, both genders), broiler chickens (Ross 308, both genders), turkeys (BUT 6, males), Peking ducks (Cherry Valley, both genders) and Muscovy ducks (Canedins R51, males).Depending on live weight, age, plumage condition and body position, LB hens occupied an average area between 401 cm2 and 542 cm2, LSL hens between 353 cm2 and 445 cm2, broiler breeder females between 440 cm2 and 537 cm2, broiler breeder males 623 cm2 up to 945 cm2, broiler chickens up to 434 cm2, male fattening turkeys up to 1808 cm2, Muscovy drakes up to 873 cm2 and Peking ducks up to 627 cm2.The values can be regarded as necessary minimum spatial requirements for the measured poultry species and genotype.The current method offers the potential to record the area occupied by animals exhibiting species-specific behavioural patterns.

Density-Dependent Spacing Behaviour and Activity Budget in Pregnant, Domestic Goats (Capra hircus).

Very little is known about the spacing behaviour in social groups of domestic goats (Capra hircus) in the farm environment. In this experiment, we studied interindividual distances, movement patterns and activity budgets in pregnant goats housed at three different densities. Norwegian dairy goats were kept in stable social groups of six animals throughout pregnancy at 1, 2 or 3 m2 per individual and their spacing behaviours (i.e. distance travelled, nearest and furthest neighbour distance) and activity budgets (e.g. resting, feeding, social activities) were monitored. Observations were made in the first, second and last thirds of pregnancy in the mornings, at noon and in the afternoons of each of these phases (4.5 hours per observation period). The findings show that goats held at animal densities of 2 and 3 m2 moved longer distances when they had more space per animal and kept larger nearest and furthest neighbour distances when compared to the 1 m2 per animal density. Less feeding activity was observed at the high animal density compared to the medium and low density treatments. The phase of gestation also had an impact on almost all behavioural variables. Closer to parturition, animals moved further distances and the increase in nearest and furthest neighbour distance was more pronounced at the lower animal densities. During the last period of gestation, goats spent less time feeding and more on resting, social behaviours and engaging in other various activities. Our data suggest that more space per goat is needed for goats closer to parturition than in the early gestation phase. We concluded that in goats spacing behaviour is density-dependent and changes with stages of pregnancy and activities. Finally, the lower density allowed animals to express individual preferences regarding spacing behaviour which is important in ensuring good welfare in a farming situation.

Effect of pasture size on behavioural synchronization and spacing in German Blackface ewes (Ovis aries)

This study aims to assess plot size related changes in spacing and behavioural synchronization in a herd of 14 German Blackface ewes kept on three different pasture sizes: S (126m2), M (1100m2), and L (11,200m2). In direct field observations, behaviour and nearest neighbour distance were recorded individually. Additionally, interindividual and nearest neighbour distances were derived from aerial photographs of the herd taken on plot sizes S and M. Nearest neighbour distances <1m accounted for more than 60% of observations, and were more frequent on plot size L than on plot sizes S (Z=3.3; p<0.01) and M (Z=3.2; p<0.01). Average interindividual distances were significantly smaller on S (4.89±2.62m) than on M plots (5.99±3.06m; t=7.3; p<0.01). Synchronization tended to increase with plot size (K(S)=0.42; K(M)=0.52; K(L)=0.66), but was not accompanied by a concomitant increase in dispersion. Aerial photography proved a valuable tool in the analysis of spacing behaviour as intraindividual repeatability of the derived distances was highly significant (Kendall’s W between 0.32 and 0.58; p<0.01). The sheep kept small distances on all plot sizes, thus the high degree of behavioural synchronization might be mainly attributed to the motivation for close proximity to any conspecific.

Modelling the emergence of coordinated collective motion by minimizing dissatisfaction

Coordinated collective motion (CCM) has been recently studied using agent-based simulations by applying three behavioural rules: repulsion, attraction and alignment. But these rules are so similar to the expected group behaviour that it can hardly be labelled emergent. We developed an agent-based model that produces CCM using a set of low-level dyadic interaction rules. The agents change their positions with regard to other agents in order to minimize their own dissatisfaction with their inter-individual distances. To test the emergence of CCM, several simulation experiments were performed. The results show that the agents were able to achieve CCM after a few thousand time steps, and that the bigger the area perceived by them, the more coordinated and cohesive the group motion became. An increased memory span and capacity to remember other agents’ identities improved cohesion and coordination. The relationship with biological referents is discussed.

Tracking the startle response of guppies Poecilia reticulata in three dimensions.

A three-dimensional analysis of startle behaviours of guppies Poecilia reticulata, in dyads or alone, from two populations that show distinct differences in shoaling behaviour was performed. During the first few seconds after a startling stimulus, changes in behaviour, which could be critical if an individual is to survive a predatory attack, and the interactions between pairs of P. reticulata were examined. The enhanced social interactions immediately after the stimulus, as a proxy for shoaling behaviour, and their dissipation were quantified. Social (individuals tested in dyads) v. asocial (tested alone) responses to the startling stimulus were also compared. The three-dimensional reconstruction, from a two-camera, high-frame-rate tracking system allowed for the tracking of the individuals' speed and speed recovery and, for P. reticulata in dyads, interindividual distance and orientation. For the dyads from the high-predation population, the closer the individuals were to each other, the more likely they were to be parallel, but no correlation was found for the low-predation P. reticulata. The startle response of P. reticulata comprised the following sequence: freezing, darting and skittering and recovery to pre-stimulus swimming behaviour. Upon repeated encounters with the stimulus, a reduced shoaling and startle response was observed, although the rate of reduction was faster in P. reticulata from the high-predation population than those from the low-predation population. The results are discussed in light of what is known about the anti-predator behaviour of this species.

Different habitat suitability models yield different least-cost path distances for landscape genetic analysis

Habitat suitability models (HSMs) are used to describe and predict species distributions based on multiple ecological variables and species occurrence data. HSMs may also provide a probabilistic identification of least-cost path (LCP) distances in landscape genetics. However, while several studies used HSMs for these purposes, the performance of different HSMs in landscape genetic analysis and, therefore, the consequences of model choice have not been carefully explored. In this study, we used a large dataset of wolf genotypes (Canis lupus; n=923) that were non-invasively sampled in the central and northern Italian Apennines and western Alps, aiming (i) to estimate LCP distances derived from ten different HSMs and (ii) to quantify the correlation between inter-individual genetic and LCP distances using three statistical procedures: partial Mantel tests, multiple regression on distance matrices (MRDM) and linear mixed effect models. All LCP distances based on HSMs explained genetic distances better than Euclidean distances, irrespective of the applied landscape genetic statistical test. However, LCP distances derived by different HSMs were significantly different (paired t-test, P≤0.0001), especially between “flexible discriminant analysis” (FDA) and “boosted regression trees” (BRT) models. LCP distances derived from “factorial decomposition of Mahalanobis distances” (MADIFA) in MRDM showed the highest regression coefficient (β) with genetic distances, indicating a strong correlation between LCPs and genetic distances. Results from our case study suggest that different HSMs should be compared and model-choice procedures applied to identify the best fitting HSM in landscape genetic analysis.

To be or not to be horned—Consequences in cattle

In cattle, both males and females of horned breeds have permanent horns which are directly connected with the frontal sinuses of the skull and are growing during their entire life. To date a large proportion of cattle is disbudded or dehorned, or increasingly bred for polledness. This review explores the possible consequences of cattle having horns or not, both for the cattle themselves and for the farmers. During natural selection horns may have provided advantages concerning predator defence or in competition for mates and resources. Additionally, there are indications that horns serve as honest signals in mate selection, as they reflect individual health. Presence or absence of horns will likely affect quality and quantity of social interactions as well as social relationships in a herd. It clearly affects the way of cattle fighting. Only few studies deal with social behaviour in horned herds in comparison to hornless herds, and they rely on single herd observations or need to be interpreted with caution because of confounding factors. However, it appears that horned cattle attempt to keep greater inter-individual distances and resort less to physical interactions than hornless cattle, leading to more stable social relationships under suitable environmental conditions and management. Cattle may, furthermore, use horns for self-grooming of body regions which are otherwise out of reach. Even less is known on possible physiological functions of horns. While there is good evidence regarding a thermoregulatory function, other claimed functions, e.g. concerning digestion, have not been scientifically investigated yet. Although farmers in favour of keeping horned cattle, for instance for ethical reasons, are able to reduce the increased risk of animal injuries and human accidents by providing improved housing and management conditions and maintaining a good human–animal relationship, it may be economically advantageous to keep hornless cattle. If disbudding/dehorning is carried out, the consequences in terms of stress and pain can be alleviated by a combination of local anaesthesia and anti-inflammatory treatment, as well as sedation of animals insufficiently used to handling. However, possible negative side effects of sedation should be addressed in future studies. Furthermore, the possibility of longer lasting pain after disbudding/dehorning is not sufficiently investigated yet. Finally, it is an open question whether the removal of horns alters the social behaviour of the animals, or is a mere symptomatic measure to adjust them to husbandry conditions that are insufficiently adapted to the species-specific needs of cattle.

The first description of dominance hierarchy in captive giraffe: not loose and egalitarian, but clear and linear.

Wild giraffes live in extensive groups in the fission fusion system, maintaining long social distances and loose social bonds. Within these groups, resources are widely distributed, agonistic encounters are scarce and the dominance hierarchy was reported in males only, while never deeply analysed. In captivity, the possibility to maintain inter-individual distances is limited and part of the resources is not evenly distributed. Consequently, we suggest that agonistic encounters should be more frequent, leading to the establishment of the dominance hierarchy. Based on the differences in resource-holding potential, we suggested that the rank of an individual would be affected by age and sex. Based on hypotheses of prior ownership, we tested whether rank was positively affected by the time spent in a herd and whether it was stable in adult females, which were present long-term in the same herd. We originally monitored four herds of Rothschild giraffes (Giraffa camelopardalis rothschildii) in Dvůr Králové zoo (n = 8), Liberec zoo (n = 6), and two herds in Prague zoo: Prague 1 (n = 8) and Prague 2 (n = 9). The Prague 1 and Prague 2 herds were then combined and the resulting fifth herd was observed over three consecutive years (2009, 2010, and 2011) (n = 14, 13, and 14, respectively). We revealed a significantly linear hierarchy in Dvůr Králové, Prague 2 and in the combined herd in Prague. Rank was significantly affected by age in all herds; older individuals dominated the younger ones. In females, rank was positively affected by the time spent in the herd and adult females in Prague maintained their rank during three consecutive years. This study represents the first analysis of the dominance hierarchy in the captive giraffe, and discusses the behavioural flexibility of the social structure in response to monopolisable resources in a captive environment.