Seasonal serum urea-creatinine ratios in wild and captive American badgers, Taxidea taxus

1. Blood samples were taken from 22 American badgers in the field during different seasons and analysed for urea and creatinine. 2. The urea-creatinine ratio (U/C) of these animals did not decrease during the winter as previously reported for black bears. This suggests that the badger, unlike the bear, does not demonstrate a winter physiological state of protein conservation. 3. This may be the consequence of intermittent ingestion of protein by the badger during the winter, or due to biochemical mechanisms unique to the bear which allows for protein turnover and resynthesis. 4. Captive badgers fasted in the laboratory during the winter also did not exhibit lower U/C ratios and protein catabolism, compared to a summer fast, thereby supporting the latter hypothesis that badgers do not have an adjustment in protein catabolism during the winter season.     

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.     

The ‘omnivorous badger dilemma’: towards an integration of nutrition with the dietary niche in wild mammals

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Seasonal variations in physiological indices of adult female white-tailed deer in Texas

Seasonal variations in blood chemistry, urine chemistry, fat reserves, and crude protein levels of rumen contents were determined for free-ranging adult female white-tailed deer (Odocoileus virginianus Zimmermann) in central Texas. Seasonal variations (P less than 0.05) existed for serum total protein, albumin, globulin, albumin/globulin ratios, blood urea nitrogen (BUN), cholesterol, alkaline phosphatase, creatinine, phosphorus, and sodium; and urinary urea/creatinine (U/C) ratios, rumen crude protein, the kidney fat index (KFI), femur marrow fat (FMF), and dressed weights. Variations in BUN, urinary U/C ratios, dressed weights, KFI, and FMF were attributed partially to the nutritional demands of late gestation and lactation.     

Winter hibernation and body temperature fluctuation in the Japanese badger, Meles meles anakuma

This study examined seasonal changes in body weight, hibernation period, and body temperature of the Japanese badger (Meles meles anakuma) from 1997 to 2001. Adult badgers showed seasonal changes in body weight. Between mid-December and February, badger activity almost ceased, as the animals remained in their setts most of the time. Adult male badgers were solitary hibernators; adult females hibernated either alone or with their cubs and/or yearlings. The total hibernation period of Japanese badgers ranged from 42 to 80 days, with a mean length of 60.1 days. Japanese badgers did not always spend the winters in the same sett, although they seldom changed setts during hibernation. I equipped a male cub with an intraperitoneally implanted data logger to record its body temperature between November and April, while the cub hibernated with its mother. Over the winter, the body weight of the cub decreased from 5.3 kg to 3.6 kg, a weight loss of 32.1%, and its body temperature ranged from 32.0 to 39.8 degrees C. The mean monthly body temperature was 35.1 degrees C in December, 34.8 degrees C in January, 35.9 degrees C in February, 37.1 degrees C in March, and 37.4 degrees C in April, so the monthly decrease in body temperature of this cub was not great. The results indicate that during hibernation, when body temperature is low, there is likely considerable economy of energy and a reduced demand for adipose reserves.     

Plasma urea, creatinine, and urea: creatinine ratio in reindeer (Rangifer tarandus tarandus) and in Svalbard reindeer (Rangifer tarandus platyrhynchus) during defined feeding conditions and in the field.

Variation in plasma urea and creatinine concentration and plasma urea:creatinine ratio (U:C) were studied in semidomestic free-ranging reindeer (Rangifer tarandus tarandus) on the Norwegian mainland, in wild Svalbard reindeer (Rangifer tarandus platyrhynchus), and in captive reindeer maintained either on a lichen-based diet or a protein-rich concentrate to investigate whether these parameters could be used as indicators of the nutritional status of reindeer. In the mainland animals, plasma creatinine concentration was high in winter and early spring and decreased by two-thirds toward the summer. The overall range in mean plasma creatinine concentration (+/-SE) was from 90+/-1.26 to 280+/-2.88 micromol/L. Mean plasma urea concentration (+/-SE) varied from 2.46+/-0.10 in winter up to 17.44+/-0.29 mmol/L in summer and autumn. Month of sampling explained 65% and 90% of the variation in plasma urea and creatinine concentrations, respectively, indicating that seasonality in the diet had the greatest influence on these parameters. Reindeer given lichens as the only feed showed an increase in plasma creatinine and a decrease in plasma urea concentration. Food restriction caused a temporary elevation in urea level but had no significant effect on plasma creatinine concentration. The slight effect of energy intake on urea and creatinine levels was supported by the fact that severe undernutrition in the Svalbard reindeer population had only a small effect on plasma urea and creatinine levels. Protein-rich pellet feed increased plasma urea from around 3 mmol/L to above 10 mmol/L and reduced creatinine concentrations to less than 100 micromol/L, suggesting that the protein content of forage is an important determinant of these blood parameters. Mean U:C ratio (+/-SE) in plasma varied from 8.9+/-0.28 to 120.8+/-1.88. Ratios above 20 appeared when protein intake was low and energy intake was restricted or when protein intake was high. Low ratios occurred when protein intake was low but energy intake adequate. Plasma urea and creatinine concentrations and the U:C ratio showed complex dynamics that were affected by both season and the protein and feed intake. We conclude that they appear to be difficult to interpret as single measures of nutritional status of reindeer.     

Annual and circadian activity patterns of badgers (Meles meles) in Białowieża Primeval Forest (eastern Poland) compared with other Palaearctic populations

Aim The annual and circadian rhythms and duration of activity of Eurasian badger Meles meles (Linnaeus 1758) were studied in a low‐density population inhabiting the primeval woodland in the European temperate zone. Results were compared with available data from the literature on seasonal changes in body mass and winter inactivity of badgers from across the Palaearctic region. Location Field work was carried out in Bia?owie?a Primeval Forest, eastern Poland. Biogeographical variation was reviewed based on twenty‐three localities in the Palaearctic region (from Western Europe to Central Siberia). Methods Thirteen badgers were radio‐collared in 1997–2001. Their circadian activity was sampled by 24‐h sessions of continuous radio‐tracking with location taken at 15‐min intervals. Annual activity was studied by radio‐tracking and inspections of setts. Earthworm (badgers’ main food) biomass was estimated in four types of habitats throughout the year. Results Badgers were nocturnal with one long bout of activity. Their rhythms of diel activity differed between spring and autumn, and between adult and subadult individuals. On average, badgers emerged from setts at 19:00 hours and returned to them at 03:42 hours. The highest level of activity was recorded between 20:00 and 03:00 hours. Duration of daily activity was, on average, 8.2 h day^?1, but varied significantly between seasons. The seasonal changes were inversely related to the abundance of earthworms. Duration of activity also depended on daily temperature, especially in the cold season. In winter, badgers stayed inactive for an average of 96 days per year. In autumn, they built fat reserves and their body mass nearly doubled compared with the spring values. The literature review on annual cycle of activity and body mass changes in Eurasian badgers showed that fat storage and duration of winter sleep strongly depended on climate (best approximated by January mean temperature). In regions with warm climates, badgers were active year round and their body mass changed only slightly, while in regions with severe winters badgers increased their body mass twofold from spring to autumn, and stayed inactive for as long as 6 months per year. Main conclusion We propose that, in the temperate and boreal zones of the Palaearctic region, the ultimate determinant of biogeographical variation in badgers’ annual activity is the winter shortage of earthworms, which are the main component of badger diet.     

In situ adaptive response to climate and habitat quality variation: spatial and temporal variation in European badger (Meles meles) body weight

Variation in climatic and habitat conditions can affect populations through a variety of mechanisms, and these relationships can act at different temporal and spatial scales. Using post‐mortem badger body weight records from 15 878 individuals captured across the Republic of Ireland (7224 setts across ca. 15 000 km²; 2009–2012), we employed a hierarchical multilevel mixed model to evaluate the effects of climate (rainfall and temperature) and habitat quality (landscape suitability), while controlling for local abundance (unique badgers caught/sett/year). Body weight was affected strongly by temperature across a number of temporal scales (preceding month or season), with badgers being heavier if preceding temperatures (particularly during winter/spring) were warmer than the long‐term seasonal mean. There was less support for rainfall across different temporal scales, although badgers did exhibit heavier weights when greater rainfall occurred one or 2 months prior to capture. Badgers were also heavier in areas with higher landscape habitat quality, modulated by the number of individuals captured per sett, consistent with density‐dependent effects reducing weights. Overall, the mean badger body weight of culled individuals rose during the study period (2009–2012), more so for males than for females. With predicted increases in temperature, and rainfall, augmented by ongoing agricultural land conversion in this region, we project heavier individual badger body weights in the future. Increased body weight has been associated with higher fecundity, recruitment and survival rates in badgers, due to improved food availability and energetic budgets. We thus predict that climate change could increase the badger population across the Republic of Ireland. Nevertheless, we emphasize that, locally, populations could still be vulnerable to extreme weather variability coupled with detrimental agricultural practice, including population management.     

Antibodies to Mycobacterium bovis in wild carnivores from Doñana National Park (Spain)

We conducted a retrospective serologic survey for antibodies against the MPB70 protein of Mycobacterium bovis in wild carnivores from Do?ana National Park (southwestern Spain). Serum samples from 118 red foxes (Vulpes vulpes), 39 Iberian lynx (Lynx pardinus), 31 Eurasian badgers (Meles meles), five Egyptian mongoose (Herpestes ichneumon), four European genet (Genetta genetta), and one Eurasian otter (Lutra lutra) were analyzed using an indirect competitive enzyme-linked immunoassay. Antibodies against the MPB70 protein of M. bovis were detected in seven badgers, five foxes, and one lynx. The frequency of positive animals was significantly higher in badger (23%) than in lynx (3%) and fox (4%). Antibodies were not detected in other species. Annual antibody frequency peaked at 38% in badgers and 11% for red fox. These species may contribute to persistence of bovine tuberculosis in Do?ana.     

Absence of antibodies against canine distemper virus in free-ranging populations of the Eurasian badger in Great Britain

Canine distemper virus (CDV) is a serious disease of wild carnivores throughout the world. In Europe, infection has been detected in several carnivores including the Eurasian badger (Meles meles). In the present study 182 badger blood samples were collected from an intensively studied population of wild badgers in southwestern England (January-July, 1997), and a further 286 from throughout southern Britain (June 1996-November 1998). A neutralizing peroxidase-linked antibody test was used for the detection of antibodies against CDV. All the samples were negative for CDV antibodies, suggesting that in contrast to mainland Europe, the disease may be either absent or maintained at low levels in British badgers.     

Reports on badgers Meles meles in Dutch newspapers 1900–2013: same animals,different framings?

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Pathogen and rodenticide exposure in American badgers (Taxidea taxus) in California

Urban and agricultural land use may increase the risk of disease transmission among wildlife, domestic animals, and humans as we share ever-shrinking and fragmented habitat. American badgers (Taxidae taxus), a species of special concern in California, USA, live in proximity to urban development and often share habitat with livestock and small peridomestic mammals. As such, they may be susceptible to pathogens commonly transmitted at this interface and to anticoagulant rodenticides used to control nuisance wildlife on agricultural lands. We evaluated free-ranging badgers in California for exposure to pathogens and anticoagulant rodenticides that pose a risk to wildlife, domestic animals, or public health. We found serologic evidence of badger exposure to Francisella tularensis, Toxoplasma gondii, Anaplasma phagocytophilum, canine distemper virus, and three Bartonella species: B. henselae, B. clarridgeiae, and B. vinsonii subsp. berkhoffii. Badger tissues contained anticoagulant rodenticides brodifacoum and bromadiolone, commonly used to control periurban rodent pests. These data provide a preliminary investigation of pathogen and toxicant exposure in the wild badger population.     

Blood biochemistry reference values for wild juvenile loggerhead sea turtles (Caretta caretta) from Madeira archipelago

Standard biochemical parameters were determined in wild juvenile loggerhead sea turtles Caretta caretta living offshore Madeira Island, northeast Atlantic. We analyzed the influence of age, sex, sea surface temperature, and body condition index on biochemical parameters including uric acid, total bilirubin, total cholesterol, creatinine kinase (CK), glucose, total protein, urea nitrogen, lactate dehydrogenase, aspartate aminotranspherase (AST), gamma-glutamyl transferase (GGT), albumin, alkaline phosphatase (ALP), sodium (NA), potassium (K), chloride, calcium, phosphorus, and magnesium. Significant positive correlations were found between turtle body size and total cholesterol, total protein, and albumin. Total protein and the enzymes AST and CK were lower than reported levels in adults. Calcium levels were lower than those reported in adult or captive turtles, but similar to wild juveniles from Australian waters, and were interpreted as normal for this age category. These data may be useful to evaluate the health status of stranded or injured animals and to improve veterinary care at rehabilitation centers.     

Effects of photoperiod, melatonin implants and castration on molting and on plasma thyroxine, testosterone and prolactin levels in the European badger (Meles meles)

1. The seasonal molt, which lasts six months in the badger, begins in mid-July and ends at the beginning of winter. It occurs under natural long-day conditions, following the seasonal drop in plasma testosterone levels, concomitant with high levels of thyroxine and prolactin. 2. To examine the role of the different factors involved (day length, prolactin, thyroxine, testosterone), different groups of badgers, divided into subgroups of castrated or intact animals, were subjected to the influence of long days (20L: 4D), short days (4L:20D) or the effect of subcutaneous melatonin implants. 3. In all cases, castration resulted in a significantly earlier onset of molting 1-3 months, depending on the group, regardless of the experimental conditions (20L:4D, 4L:20D, melatonin). 4. However, molting started earliest in animals subjected to long days, irrespective of whether they were castrated or intact. 5. In the melatonin-implanted badgers, molting started either early (castrated animals), or late or not at all (intact animals). 6. Lastly, in castrated badgers subjected to experimental photoperiods (short days or long days) or melatonin implants, the period of molting was shortened from 6 months (intact outdoor animals) to 4 months. 7. The advance in shedding was always related to an early drop in testosterone (or an absence of testosterone in the castrated animals) and to a higher or earlier increase in thyroxine levels.(ABSTRACT TRUNCATED AT 250 WORDS)     

The distribution of Eurasian badger, Meles meles, setts in a high-density area: field observations contradict the sett dispersion hypothesis

Are setts significant determinants of badger socio‐spatial organisation, and do suitable sett sites represent a limited resource, potentially affecting badger distributions? The factors determining diurnal resting den, or sett, location and selection by Eurasian badgers Meles meles L. were investigated in Wytham Woods, Oxfordshire. 279 sett sites were located. The habitat parameters that were associated with the siting of these setts were analysed and associations were sought between sett location and character and the body condition and body weight of resident badgers Habitat characteristics in the vicinity of setts were significantly different from randomly selected points. Badgers preferentially selected sites with sandy, well‐drained soils, situated on NW‐facing, convex and moderately inclined slopes at moderate altitude. There was no evidence that sett morphology (number of entrances, sett area, number of hinterland latrines) was affected by the surrounding sett site habitat characteristics. Mean body weight was significantly higher for badgers occupying territories with setts in sandy soils, situated on NW‐facing slopes, than in territories with less optimal sett characteristics. Contrary to the hypothesis that the availability of sett sites was limiting, and therefore that sett dispersion dictates the spatial and social organisation of their populations, the badgers were clearly able to excavate new setts. On our measures, these new setts were not inferior to old established ones, despite occupying subsequently exploited sites; the badgers utilising these new setts had neither lighter body weights nor poorer body condition scores. During the period of our study badgers have manifestly been able to dig numerous new setts; as satisfactory sites still remain available, this indicates that suitable sett sites have not yet become a limiting resource. There was no relationship between sett age and the characteristics of the site in which it was dug, as suitable sites were not limiting. Significantly, population expansion during the decade 1987–1997 was not constrained by lack of setts, rather the main proliferation in setts occurred after the population size had peaked in 1996. Some implications for the management and conservation of the Eurasian badger are considered.     

Spatio-temporal ecology and density of badgers <Emphasis Type="Italic">Meles meles</Emphasis> in the Swiss Jura Mountains

This study reports for the first time data on the spatio-temporal ecology of badgers living in a cold and wet mountain region (Swiss Jura Mountains). The home range, movements, activity patterns and habitat use of three badgers (two males, one female) were examined using radiotelemetry. Average home range size was 320 ha (MCP 100%), but the ranging behaviour of badgers varied at a seasonal scale. As in other regions, badgers were strictly nocturnal or crepuscular and showed a marked reduction of activity in the winter period. From spring to autumn, animals were active for an average (±SD) of 8.1 ± 2.4 h and travelled up to 9,460 m each night (mean±SD, 5,160 ± 2,600 m). The nightly distance travelled by badgers was positively correlated with their travel speed, the duration of the activity period and the used area, but not with night length. Year-round, the radio-collared animals avoided pastures and the vicinity of houses during their night trips. In winter and spring, individual badgers used forests and wooded pastures more than expected according to their availability, whereas cereal fields were actively selected in summer and autumn. Den-watching, night-lighting and radio-tracking data suggest that badgers live in pairs in this wet and cold region. Population density estimates range from 0.4 to 1.5 individuals/100 ha. We discuss the importance of trophic resources and climate as factors influencing badger behavioural ecology.     

Camera trap records of leucistic Eurasian badgers (Meles meles) in central Norway

Coat coloration plays an important role in communication, camouflage, and sexual selection in animals. Genetic mutations can lead to anomalous colorations such as melanism and leucism, where animals appear, respectively, darker or lighter than normal. Reporting abnormal coloration in wild animals is an important first step to understand the distribution, prevalence, and potential fitness consequences of these rare events. Here, we report several records of suspected leucism in the Eurasian badger (Meles meles) in a population in central Norway. Several camera traps recorded at least two leucistic individuals between 2017 and 2020. It took considerable effort, almost 400,000 camera trap nights over a period of 10 years all over Norway, to obtain a total of eleven records of leucistic badgers, indicating the rarity of this phenotype. It is unclear what has caused the presence of multiple leucistic badgers in a single population, but recent colonization and lack of predators might have played a role. Due to our observations, future studies can now be developed to study the underlying mechanisms and potential consequences of leucism in this badger population. The increasing use of networks of camera traps in wildlife research will provide new opportunities to record rare coloration in wild animals.     

Animal-defined resources reveal nutritional inadequacies for woodland caribou during summer–autumn

Populations of woodland caribou (Rangifer tarandus caribou) are declining throughout their range and many are at risk of extirpation, yet the role of nutrition in these declines remains poorly understood, in part owing to a lack of information about available nutritional resources during summer. We quantified rates of intake of digestible protein and digestible energy by tame caribou foraging in temporary enclosures in the predominant plant communities of northeastern British Columbia, Canada, during summer–autumn and compared intake rates to daily requirements for protein and energy during lactation. We tested hypotheses related to the nutritional adequacy of the environment to support nutritional requirements during lactation (with and without replenishment of body reserves) and simulated scenarios of foraging by caribou in these plant communities to better understand how wild caribou could meet nutritional demands on these landscapes. Nutritional resources varied among plant communities across seasonal, ecological, and successional gradients; digestible energy intake per minute and per day were significantly greater in younger than older forests; dietary digestible energy and per-minute and daily intake of digestible protein were greater, though not significantly so, in younger than older forests; and dietary digestible protein was greater in older than younger forests, though differences were not significant. Tame caribou were unable to satisfy protein and energy requirements during lactation, even without replenishment of body reserves, at most sites sampled. Further, foraging simulations suggested widespread nutritional inadequacies on ranges of wild caribou. Selection for habitats offering the best nutrition may mitigate some nutritional inadequacies, but given low availability of vegetation communities with high nutritional value, performance (e.g., calf production, growth, replenishment of body fat and protein) of caribou may be depressed at levels of nutrition documented herein. Our results, coupled with recent measurements of body fat of wild caribou in northeastern British Columbia, refute the hypothesis that the nutritional environment available to caribou during summer in northeastern British Columbia is adequate to fully support nutritional demands of lactating caribou, which has implications to productivity of caribou populations, recovery, and conservation.     

Badgers and Badger Fleas: Strategies and Counter-Strategies

We examined the broad hypothesis that one function of grooming by the European badger (Meles meles) is to disadvantage (possibly by removal) parasitic badger fleas (Paraceris melis). We pursued two lines of investigation. First, we used infra‐red video analysis to examine the body areas reached by self‐ and allo‐grooming badgers. We expected that if grooming was important to disadvantage fleas then allo‐grooming would cover areas that could not be reached by self‐grooming. Badgers preferred dorsal allo‐grooming and ventral self‐grooming, and when combined, the overall amount of grooming per square centimetre of skin area provided even body coverage, pointing to a hygienic function, rather than a purely social function. Secondly, we examined fleas’ responses to simulated fur disturbance, characteristic of grooming. If grooming had no flea disadvantage effect, we would expect no response from fleas, and no directionality in their movement away from direct touch. The number of fleas encountered rapidly declined in successive 10‐s counts during simulated ‘grooming’ at the same site. When badgers were ‘groomed’ on alternate sides (mimicking the badgers’ rapid alternation of grooming position), there was a marked increase in fleas when grooming resumed on the original side. Similarly, when ‘grooming’ was suspended for 40 s, there was an initial increase in the number of fleas when ‘grooming’ was resumed. Disturbed fleas tended to run downwards relative to gravity and towards the posterior of the badger, following the direction of hair growth. This contrasted with the behaviour of fleas removed from badgers which tended to run upwards and jump. We concluded that the pattern of badger grooming and the fleas’ response to disturbance was consistent with a hypothesis that badgers and badger fleas have strategies and counter strategies to maximize and minimize contact (respectively) during grooming.     

Age, sex, and condition as predictors of moult and the efficacy of a novel fur-clip technique for individual marking of the European badger (Meles meles)

The European badger ( Meles meles ) moults once a year. In our study site in lowland England, pelage replacement of the guard hairs and a protracted period of fur growth (follicular anagen) occur between May and early November, with a peak in July. The precise timing of the moult depends on the age and condition of the badger. Yearling badgers undergo moult significantly earlier than adults. Adult females that have lactated, moult significantly later than other classes of adult, delaying the moult until autumn which corresponds to an annual period of food abundance. Lactation was significantly associated with poor condition in these badgers. It was not possible to determine whether delayed moult was due to poor condition per se , or due to some other physiological consequence of lactation, e.g. hormonal changes. We hypothesize that delay of moult in laclating/poor condition individuals has the adaptive consequence of delaying the metabolic costs of pelage replacement from a time of energy deficit until a time of relative plenty.
These findings are of practical importance to a novel solution to the problem of individually marking badgers during observational studies. The technique involves clipping the dark band near the tips of the badger's guard hairs to reveal the white under-fur and produce patterning of the coat. The highly contrasting marks were well suited to visual identification during observations under low light and infra-red illumination, and they allowed a large number of individuals (over 80 in our study) to be distinctively marked. The mark persists until the badger undergoes its single annual moult, or until three months of the active phase of fur growth have passed. Clip marks on adults made in late August had the greatest longevity, with 80% still visible after nine months. Though clipping had no significant effect on body condition in our study site, it should be cautiously applied with individuals in poor condition or in cold climates.