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.     

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.     

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.     

Social organization and movement influence the incidence of bovine tuberculosis in an undisturbed high-density badger Meles meles population

1. The culling of European badgers Meles meles has been a central part of attempts to control bovine tuberculosis (TB) in British cattle for many years. Recent results, however, indicate that this approach could in practice enhance disease spread. 2. This paper looks at the relationship between TB incidence and badger ecology in a high-density population in south-west England, which has been the subject of a long-term intensive study. The principal aims were to relate the probability of TB incidence, as detected by culture of clinical samples (i.e. excretion of bacilli), at the level of the individual and of the social group to demographic processes, movement, social organization and disease dynamics. 3. The probability of an individual being an incident case was greater in groups where TB was already present, although this was less influential in groups that were subject to some instability in numbers. Both individuals and groups were more likely to be incident cases where the social group was diminishing in size, although no relationship was observed with group size itself. This suggests that the process of group size reduction rather than group size per se has most influence on disease dynamics. The likelihood that either an individual or a group was an incident case was positively correlated with both individual and group-level movement. When the proportion of females in a social group was high, the positive association between movement and incidence was found to be more pronounced and there was a significantly higher probability of incident cases among males. 4. These relationships highlight the importance of social structure in driving TB transmission dynamics in this stable, high-density badger population. The results support the idea that a stable social structure mitigates against new incident cases of disease, and are consistent with the contention that badger culling may create the social circumstances for enhanced transmission of TB.     

The helminth parasites of the badger (Meles meles) in Cornwall

The helminth parasites of 118 badgers from Cornwall are recorded. Nematode infestations are common. The five species found are Capillaria? erinacei, Molineus patens, Uncinaria stenocephala, Aelurostrongylus falciformis and Strongyloides sp. Cestode infestations appear to be rare, the species recorded being Mesocestoides lineatus and Dilepis undula. Similarly only a single trematode, Ityogonimus lorum, is recorded.     

Investigation of badger (Meles meles) setts using soil resistivity measurements

Eight badger (Meles meles L.) Setts (two main setts, four subsidiaries, one annex and one outlier) were surveyed by means of soil resistivity and magnetometry techniques, of a type normally used for the detection of buried archaeological remains. The results were compared with data concerning the underground sleeping locations adopted by radio-collared badgers in the same setts. Of the eight resistivity surveys, six gave sufficiently detailed results for the overall size of the setts in question to be determined and for some features of the constituent tunnel systems to be discerned. Areas of low resistivity matched locations where radio-collared badgers were found to sleep, so presumably corresponded with underground tunnels and chambers. Magnetometry surveys were not successful, probably because tunnels and chambers were too deep to be detected by this method.     

Craniometric variation in the Eurasian badger, Meles meles

A multivariate examination of cranial variation within and between European populations of Meles meles (L.) revealed that populations from Ireland, Great Britain, Norway, and the Slovak Republic could be differentiated both by cranial form and by the degree of sexual dimorphism exhibited. Irish material was characterized by low sexual dimorphism, particularly when compared to Slovak specimens. Badgers from the British Isles had larger skulls than other samples and were more similar to each other than they were to badgers from mainland Europe. Size played a greater role in differentiating samples of female badgers than it did in males. Significant variation occurred within the British Isles, with individual samples being highly differentiable. There was, however, little relationship between morphological similarity and geographic proximity. We contend that macrogeographical (between-country) variation in the species is primarily determined by historical factors and adaptation to current conditions, while microgeographic (within-country) variation is a result of selectively neutral processes.     

Internal structure and contents of three badger (Meles meles) setts

Three badger ( Meles meles L.) setts in the south of England, which formed a single sett complex belonging to one social group of badgers, were excavated prior to being destroyed by construction of a new road. Setts 1 and 2, classified as annexes, were excavated completely; sett 3, classified as a main sett, was only excavated partially, but its total size was estimated from the excavated portion. The setts consisted of tunnels totalling 16 m, 140 m and 879 m, respectively; contained one, nine and 50 chambers; and had five, 42 and 178 entrances. The total volume of the three setts was about 45 m³, and their construction was estimated to have required the removal of about 70 tonnes of soil. In the two smaller setts tunnels ran on a single level with an average depth of 99 cm; in the larger sett they ran on two levels with modal depths of 50 cm and 110–120 cm, respectively. All three setts contained bedding material (dry grass and plastic bags) but only the main sett contained latrines. None of the setts contained badger bones and the interiors of all three setts were remarkably clean and orderly. We discuss hypotheses as to why badgers sometimes continue to extend even large well-established setts but conclude that the survival value of very large setts remains problematical.     

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.     

Culling-induced changes in badger (Meles meles) behaviour, social organisation and the epidemiology of bovine tuberculosis

In the UK, attempts since the 1970s to control the incidence of bovine tuberculosis (bTB) in cattle by culling a wildlife host, the European badger (Meles meles), have produced equivocal results. Culling-induced social perturbation of badger populations may lead to unexpected outcomes. We test predictions from the 'perturbation hypothesis', determining the impact of culling operations on badger populations, movement of surviving individuals and the influence on the epidemiology of bTB in badgers using data dervied from two study areas within the UK Government's Randomised Badger Culling Trial (RBCT). Culling operations did not remove all individuals from setts, with between 34-43% of badgers removed from targeted social groups. After culling, bTB prevalence increased in badger social groups neighbouring removals, particularly amongst cubs. Seventy individual adult badgers were fitted with radio-collars, yielding 8,311 locational fixes from both sites between November 2001 and December 2003. Home range areas of animals surviving within removed groups increased by 43.5% in response to culling. Overlap between summer ranges of individuals from Neighbouring social groups in the treatment population increased by 73.3% in response to culling. The movement rate of individuals between social groups was low, but increased after culling, in Removed and Neighbouring social groups. Increased bTB prevalence in Neighbouring groups was associated with badger movements both into and out of these groups, although none of the moving individuals themselves tested positive for bTB. Significant increases in both the frequency of individual badger movements between groups and the emergence of bTB were observed in response to culling. However, no direct evidence was found to link the two phenomena. We hypothesise that the social disruption caused by culling may not only increase direct contact and thus disease transmission between surviving badgers, but may also increase social stress within the surviving population, causing immunosuppression and enhancing the expression of disease.