Publications by authors named "Boris Fuchs"

Animal models are a key component of translational medicine, helping transfer scientific findings into practical applications for human health. A fundamental principle of research ethics involves weighing the benefits of the research to society against the burden imposed on the animals used for scientific purposes. The utilisation of wild animals for research requires evaluation of the effects of capture and invasive sampling.

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Background: Despite centuries of research, debate remains on the scaling of metabolic rate to mass especially for intraspecific cases. The high variation of body mass within brown bears presents a unique opportunity to study the intraspecific effects of body mass on physiological variables. The amplitude of metabolic rate reduction in hibernators is dependent on body mass of the species.

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Contamination with arsenic (As), cadmium (Cd), mercury (Hg) and lead (Pb) is a global concern impairing resilience of organisms and ecosystems. Proximity to emission sources increases exposure risk but remoteness does not alleviate it. These toxic elements are transported in atmospheric and oceanic pathways and accumulate in organisms.

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Hunters can affect the behavior of wildlife by inducing a landscape of fear, selecting individuals with specific traits, or altering resource availability across the landscape. Most research investigating the influence of hunting on wildlife resource selection has focused on target species and less attention has been devoted to nontarget species, such as scavengers that can be both attracted or repelled by hunting activities. We used resource selection functions to identify areas where hunters were most likely to kill moose (Alces alces) in south-central Sweden during the fall.

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Background: Reindeer herding and husbandry is a traditional and important livelihood in Fennoscandia, and about 200,000 semi-domesticated reindeer are herded in Finland. Climatic changes, leading to ice-locked winter pastures, and encroachment of pasture-land have led to changes in reindeer husbandry, increasing the extent of supplementary or full ration feeding, which has become very common in Finland. Keeping reindeer in corrals or gathering them at permanent feeding sites will increase nose-to-nose contact between animals and they may be exposed to poor hygienic conditions.

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Lead (Pb) is heterogeneously distributed in the environment and multiple sources like Pb ammunition and fossil fuel combustion can increase the risk of exposure in wildlife. Brown bears (Ursus arctos) in Sweden have higher blood Pb levels compared to bears from other populations, but the sources and routes of exposure are unknown. The objective of this study was to quantify the contribution of two potential sources of Pb exposure in female brown bears (n = 34 individuals; n = 61 samples).

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The brown bear Ursus arctos undergoes exceptional physiological adaptions during annual hibernation that minimize energy consumption, including profound decrease in heart rate, cardiac output, and respiratory rate. These changes are completely reversible after the bears reenter into the active state in spring. In this case report, we show episodes of sinus arrest in a hibernating Scandinavian brown bear and in humans, recorded by implantable loop recorders and discuss the possible underlying mechanisms.

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Hunting has multiple consequences for wildlife, and it can be an important source of environmental pollution. Most big game hunters use lead (Pb) ammunition that shed metal fragments in the tissues of harvested animals. These Pb fragments become available to scavengers when hunters discard contaminated slaughter remains in the environment.

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Gestation and lactation have high energetic requirements. Up to three-fourths of the gestation period in moose (Alces alces) overlaps with the food-scarce period in winter. During this period, moose deal with the limited forage resources available through hypometabolism with decreased heart rate and body temperature (T).

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Background: Passive integrated transponder devices (PIT tags) are a valuable tool for individual identification of animals. Similarly, the surgical implantation of transmitters and bio-loggers can provide useful data on animal location, physiology and behavior. However, to avoid unnecessary recapture and related stress of study animals, PIT tags and bio-loggers should function reliably for long periods of time.

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Biological rhythms, such as rhythms in activity and body temperature, are usually highly synchronized and entrained by environmental conditions, such as photoperiod. However, how the expression of these rhythms changes during hibernation, when the perception of environmental cues is limited, has not yet been fully understood for all hibernators, especially in the wild. The brown bear () in Scandinavia lives in a highly seasonal environment and adapts to harsh winter conditions by exhibiting hibernation, characterized by reduced metabolism and activity.

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Exposure to lead (Pb) is a global health problem for both humans and wildlife. Despite a dramatic decline in human Pb exposure following restrictions of leaded gasoline and industry and thereby an overall reduction of Pb entering the environment, Pb exposure continues to be a problem for wildlife species. Literature on scavenging terrestrial mammals, including interactions between Pb exposure and life history, is however limited.

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  • Three medetomidine-based drug protocols were tested on wild boars to evaluate their effectiveness, with a total of 21 boars immobilized using different combinations of the drugs MTZ, MK, and MKB.
  • The MK group exhibited the longest recovery times, while MKB had issues with longer and incomplete induction, risking hyperthermia and inefficiency in capture.
  • All treatment groups experienced mild respiratory issues, but oxygen supplementation effectively improved their condition, highlighting its importance in safely immobilizing wild boars.
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  • Effective management of hunted species requires understanding how hunting impacts both individual animals and their populations.
  • Advances in biologging technology allow researchers to gather detailed data on animal behavior and physiology, enabling better assessments of these impacts.
  • In a study of moose hunted with baying dogs, findings revealed increased body temperature, heart rate, and energy expenditure during hunting, suggesting potential negative effects on the moose’s health and reproduction if disturbances are frequent.
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  • Monitoring arterial blood pressure (BP) provides a more accurate assessment of hemodynamics during wildlife chemical immobilization than relying solely on heart rate, crucial for mitigating intra- and post-operative risks.
  • The study tested the correlation between standard oscillometry and Korotkoff's technique for measuring BP in anesthetized free-ranging brown bears in Croatia and Scandinavia, with 25 bears involved in the procedures.
  • Results showed that Korotkoff's technique was significantly more reliable, with successful measurements in 93% of attempts versus 29% for oscillometry, revealing hypertension in all bears, particularly in subadults and adults compared to yearlings.
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Advantages of low input livestock production on large pastures, including animal welfare, biodiversity and low production costs are challenged by losses due to undetected disease, accidents and predation. Precision livestock farming (PLF) enables remote monitoring on individual level with potential for predictive warning. Body temperature (Tb) and heart rate (HR) could be used for early detection of diseases, stress or death.

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Free-ranging brown bears () were snared and subsequently darted with a combination of xylazine-ketamine in Croatia (n = 5) or darted from a helicopter with a combination of medetomidine-tiletamine-zolazepam in Scandinavia (n = 20). Three adults and one yearling (1 year old) bear were captured in Croatia, with one adult being captured twice. The Scandinavian bears were divided into Group A (yearlings, n = 7) and Group B (subadults, n = 2 and adults, n = 11).

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Lead (Pb) exposure is associated with adverse health effects in both humans and wildlife. Blood lead levels (BLL) of sentinel wildlife species can be used to monitor environmental lead exposure and ecosystem health. BLL analyzers, such as the LeadCare®, are validated for use in humans, assessed for use in some avian species and cattle, and are increasingly being used on wildlife to monitor lead exposure.

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  • Wolverines in northern Sweden were studied using implanted temperature loggers and GPS collars to observe their body temperature and activity patterns across seasons.
  • The research revealed that wolverines have an average body temperature of 38.5°C, with variations depending on reproductive states and a distinct decrease in temperature during pregnancy.
  • Findings showed seasonal shifts in activity, with wolverines being more active at dusk and dawn in autumn, while they displayed less consistent 24-hour rhythms during the dark winter months.
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  • Hyperphagia is essential for bears to build fat reserves before hibernation, with different diets influencing their metabolism.
  • The study compared heart rates between Asian black bears in Japan and Eurasian brown bears in Sweden, revealing that black bears experienced a significant heart rate increase during hyperphagia.
  • The findings highlight how variations in food availability affect the physiological responses of two bear species facing the same seasonal challenges.
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Postmortem body temperature is used to estimate time of death in humans, but the available models are not validated for most nonhuman species. Here, we report that cooling in an adult female moose () equipped with a rumen temperature monitor was extremely slow, with a rumen temperature of 27-28 C as late as 40 h postmortem.

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Human disturbance can affect animal life history and even population dynamics. However, the consequences of these disturbances are difficult to measure. This is especially true for hibernating animals, which are highly vulnerable to disturbance, because hibernation is a process of major physiological changes, involving conservation of energy during a resource-depleted time of year.

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Background: Sarcoptic mange, a parasitic disease caused by the mite Sarcoptes scabiei, is regularly reported on wolves Canis lupus in Scandinavia. We describe the distribution and transmission of this parasite within the small but recovering wolf population by analysing 269 necropsy reports and performing a serological survey on 198 serum samples collected from free-ranging wolves between 1998 and 2013.

Results: The serological survey among 145 individual captured Scandinavian wolves (53 recaptures) shows a consistent presence of antibodies against sarcoptic mange.

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