Plasma progesterone levels during delayed implantation in the European badger (Meles meles)

There was a biphasic pattern of progesterone secretion during the year. Delayed implantation was characterized by low concentrations from February to June, a significant (P less than 0.001) increase during July, August and September, and a return to low levels in October-November. A second significant increase (P less than 0.001) was observed in December and early January just before the presumed time of implantation.     

Dispersal and philopatry in the European badger, Meles meles

In comparison with other carnivores, European badgers, Meles meles L., show an unusually high degree of natal philopatry. In this paper, we present data on temporary and permanent movements between groups, in both male and female badgers, in a moderately high density population. A relatively small proportion of males dispersed, alone, to neighbouring territories. Dispersing males were larger than those remaining in their natal groups, and following dispersal they had higher testosterone titres and maintained testicular activity for a greater part of the year. Circumstantial evidence suggests that immigrants were the principal breeding males in their new territories. Dispersal was slightly more common in females, which dispersed away from large groups, where their chances of breeding were relatively low. Females dispersed in coalitions of 2–3, over longer distances, to territories occupied by single females. Resident females disappeared following the arrival of the immigrants, suggesting that territory 'takeovers' may have occurred. Members of both sexes also made temporary 'visits' to neighbouring territories, probably to obtain extra-group matings. Comparison with other badger populations suggests that the frequency of male dispersal declines at high population densities. In contrast, there is no effect of density on female dispersal, which occurs only rarely in some other populations. We suggest that the pattern of female/female competition is too complex to be explained solely in terms of variation in population density.     

Effects of melatonin implants on plasma concentrations of testosterone, thyroxine and prolactin in the male silver fox (Vulpes vulpes)

Melatonin administration in the form of slow-release implants advanced breeding activity in silver fox males when treatment began in June. Plasma testosterone concentrations were significantly higher in treated animals than in controls from September to November, whereas in February and March they were significantly lower. Plasma prolactin concentrations were significantly reduced immediately following melatonin treatment in June but increased to greater levels than control values and 'peaked' after 7 months. This 'peak' was associated with a rapid decrease in testosterone secretion. The normal seasonal spring rise in prolactin secretion was prevented by melatonin administration. Thyroxine values decreased and were significantly lower after 2 months of melatonin treatment.     

Seasonal distribution of road kills in the European badger (Meles meles)

Data from 984 road-killed badgers collected in the south of England during 1984 show a bimodal distribution in mortality for both sexes, with peaks in mortality occurring in spring and late summer. There was no significant difference between the total number of males and females killed, and no difference in the seasonal distribution of deaths between the two sexes. Nor was there evidence that dispersal of young animals contributes to either of the seasonal peaks in mortality. We suggest that the seasonal peaks in mortality reflect increased activity in conjunction with mating.     

Cranial variation in the European badger Meles meles (Carnivora,Mustelidae) in Scandinavia

Morphometric variation in 30 craniometric characters of 465 skulls of the European badgers (Meles meles) from across Europe was analysed. Multivariate analyses revealed that the populations from Norway, Sweden, and Finland differ from other European populations in having smaller skulls. The analyses also revealed significant differences between the ‘south‐western Norwegian’ and ‘main Fennoscandian’ forms. On average, badgers from south‐west Norway were smaller than those of the remaining Fennoscandia. Morphological differences between the ‘south‐western Norwegian’ and ‘main Fennoscandian’ populations of M. meles suggest a possible in situ semisympatric divergence since the beginning of the Holocene warming, or a complex history of two groups involving at least two colonization routes. The small‐sized Scandinavian badgers may be close to the ancestral form that used to be widespread in Denmark and throughout Europe. The animals from south‐west Norway may instead be descendants of ancestors that were the first to penetrate the southern parts of the Scandinavian Peninsula. The ‘main Fennoscandian’ badgers are likely to have been the descendants of the second wave of recolonization of Scandinavia. Specifically, they might have colonized the Scandinavian Peninsula from the east after the last glaciation.     

Costs of breeding status in the European badger, Meles meles

Compared with other mammals, reproduction is expected to be particularly costly for European badgers ( Meles meles L.) since both the gestation and mating periods occur in the winter when the animals are inactive and feed little. This paper assesses the costs of breeding status in both male and female badgers, in terms of body condition, ectoparasite load, haematology and mortality. By the end of the lactation period (May), breeding females had suffered a marked loss in body condition, although there was no such cost associated with gestation. However, females regained the weight that they had lost by the autumn following lactation. Lactating two-year-olds experienced a higher age-specific mortality than those that did not breed, but there was no difference among older females. No costs of breeding status could be detected among males at the end of the spring mating period. However, breeding males sustained testicular activity later into the summer than non-breeders, and by the autumn they had acquired more bite wounds and become anaemic. This suggests that there was a physiological cost associated with extended testicular activity in breeding males.     

Lunar-related reproductive behaviour in the badger (Meles meles)

Cyclicity in behaviours, including reproduction, in relation to the lunar cycle is widely documented in some phyla, but weak or unknown in Class Mammalia. In this paper we present long-term video surveillance data of wild Eurasian badgers Meles meles, which reveal a strong correlation between reproductive behaviour and the lunar cycle. Squat marking and raised-leg urination, which increase in frequency at times of reproductive activity, showed maxima around day 22 of the lunar cycle (i.e. new moon). These findings were supported by observations of matings, together with published records, which showed significantly higher occurrence in the lunar dark phase (last quarter to first quarter). We propose that the lunar cycle has the potential to act as a regulator of the reproductive cycle in the badger.     

Evolution of MHC class I genes in the European badger (Meles meles)

The major histocompatibility complex (MHC) plays a central role in the adaptive immune system and provides a good model with which to understand the evolutionary processes underlying functional genes. Trans-species polymorphism and orthology are both commonly found in MHC genes; however, mammalian MHC class I genes tend to cluster by species. Concerted evolution has the potential to homogenize different loci, whereas birth-and-death evolution can lead to the loss of orthologs; both processes result in monophyletic groups within species. Studies investigating the evolution of MHC class I genes have been biased toward a few particular taxa and model species. We present the first study of MHC class I genes in a species from the superfamily Musteloidea. The European badger (Meles meles) exhibits moderate variation in MHC class I sequences when compared to other carnivores. We identified seven putatively functional sequences and nine pseudogenes from genomic (gDNA) and complementary (cDNA) DNA, signifying at least two functional class I loci. We found evidence for separate evolutionary histories of the α1 and α2/α3 domains. In the α1 domain, several sequences from different species were more closely related to each other than to sequences from the same species, resembling orthology or trans-species polymorphism. Balancing selection and probable recombination maintain genetic diversity in the α1 domain, evidenced by the detection of positive selection and a recombination event. By comparison, two recombination breakpoints indicate that the α2/α3 domains have most likely undergone concerted evolution, where recombination has homogenized the α2/α3 domains between genes, leading to species-specific clusters of sequences. Our findings highlight the importance of analyzing MHC domains separately.     

Endocrine correlates of contrasting male mating strategies in the European badger (Meles meles)

In mammals, testosterone secretion is known to respond rapidly to changes in males' immediate social environment. However, such changes do not take testosterone levels below the baseline required to maintain spermatogenesis, and so do not usually affect males' fertility. In this paper, we show that individual males' patterns of testicular activity reflect their social roles in a group-living carnivore, the European badger ( Melcs metes ), leading to individual and population differences in the seasonal patterns of both testosterone secretion and, apparently, spermatogenesis. In one badger population, some males left their natal groups to become breeding males in neighbouring territories. These males had higher plasma testosterone levels, and appeared to sustain spermatogenesis for a longer period, than males which remained in their natal territories. In contrast, in a second (higher density) population, males rarely transferred away from their natal territories, and appeared not to defend access to groups of females. Instead, males made forays to mate with females in neighbouring territories. In this population males had a shorter period of testicular activity, and there were no differences in testicular activity between immigrant and natal males.     

Mediastinal lymphoma in a badger (Meles meles)

A case of mediastinal lymphoma in a free-living, adult male European badger (Meles meles), from Trento Province (northern Italy) is described. A yellow-red mass delimited by a thick fibrous capsule completely occupied the anterior mediastinum. Based on the histologic and immunohistochemical findings, a diagnosis of mediastinal lymphocytic lymphoma was made. Documentation of neoplasms in free-living species is important for comparison with domestic animals and humans and may give insight into epidemiology of these diseases. To the authors' knowledge, this is the first report of a mediastinal lymphoma in a badger.     

Body condition affects implantation date in the European badger, Meles meles

The European badger has been used for many years as a model for the study of delayed implantation. Extensive experimental work has shown that implantation, which occurs around the winter solstice, is triggered by photoperiod. This paper presents data on estimated implantation dates in a wild population of badgers, measured by ultrasound scanning. It shows that females' nutritional state prior to implantation also influences implantation date, with females in good condition implanting relatively early. Photoperiod is known to influence implantation on a timescale of months, but body condition acted on a timescale of days; thus while photoperiod may be used to set the time of breeding to correspond approximately with seasonal variation in good availability, females may use body condition to calibrate their reproduction in response to their own local conditions. Giving birth early in the year provides cubs with the maximum period of growth prior to the summer, when food availability is very low. Since females feed little during gestation and the early phases of lactation, females in good condition will be able to afford to implant earlier than those with smaller fat reserves.     

Spatial organization and territorial behaviour of the European badger Meles meles

The paper describes habitat preferences, spacing, range sizes, group composition and territorial behaviour of the European badger in a study area in southern England. Animals were followed at night with the aid of radio-location and night-vision equipment, and colour-marked food was used to establish range-size.     

Impact of culling on relative abundance of the European badger (Meles meles) in Ireland

The European Badger (Meles meles) has been implicated in the epidemiology of bovine tuberculosis in cattle populations in the Republic of Ireland. Badger populations have been subject to a culling regime in areas with chronic histories of bTB cattle herd breakdowns. Removal data from 2004 to 2010 were used to model the impact of culling on populations in areas under capture. Additionally, changes in field signs of badger activity were used as an index of abundance to support, or otherwise, the outcomes of the removal models. Significant reductions in standardised badger captures over time were found across three large study areas (total area, 1,355 km²). Assuming that all inactive setts were vacant, an overall linear trend model suggested that badger captures had decreased by 78 % for setts with 6 years of repeated capturing operations. Given the uncertainty associated with the relationship between sett activity and badger presence, we repeated the linear modelling using two ‘what if’ scenarios. Assuming that individual badgers were missed on 10 % or 20 % of occasions at inactive setts, the estimated decline over 6 years is lowered to 71 % or 64 %, respectively. The decline profile consisted of a steep initial decrease in captures within the first 2 years, followed by a more gradual decrease thereafter. The number of active openings at setts (burrows) declined significantly in all three areas; but the magnitude of this decline varied significantly amongst study areas (41–82 %). There was a significant increase in the probability of setts becoming dormant with time. The removal programme was more intense (mean, 0.45 badgers culled km^?2 year^?1) than previous experimental badger removals in Ireland but some captures may be attributed to immigrant badgers as no attempt was made to limit inward dispersal from areas not under management. Results from this study suggest that significant reductions in badger density occurred in the areas where management had taken place. Since other non-culled badger populations in Northern Ireland and Britain exhibited stable population trends, we attribute the reduction in relative abundance to the culling regime. Further studies of the dynamics of this reduction are required to quantify how it is counteracted by immigration from populations outside of culled areas.