Anal Gland Secretion Research Articles

Meet the (burying) beetles

You probably know that hard-working dung beetles keep the Serengeti Plain and cow pastures clean, but even most biologists are unaware of the efforts of another diligent group of beetles: the burying beetles of the genus Nicrophorus. Burying beetles play an important role in many ecosystems through their processing of small vertebrate carcasses. The reproductive cycle of such beetles is tied to the discovery of a recently deceased small animal (Scott, 1998; Trumbo, 1997). When beetles discover a carcass, they dig a hole beneath the body and cover it with dirt. They next remove the fur or feathers. The process is complete when the denuded corpse is covered with a layer of anal gland secretions. If more than two beetles find the carcass, males fight against males and females against females until a single pair is in control. Oviposition occurs within a day of the discovery of a carcass. The female lays her eggs in the soil; the larvae hatch about 4 days later and crawl to the carcass, which serves as nest and food source. For the first 2 days on the carcass, both parents feed the larvae regurgitated carrion and defend the carcass against other burying beetles. After this time, the larvae are able to feed themselves directly from the carcass, and the parents’ role is primarily defensive (Fetherston et al., 1990). The bout of parental behavior ends with the departure of the adult beetles from the nest: the female will remain until the larvae leave the carcass in preparation for pupation (6–8 days), while the male typically leaves a little sooner. A set of larvae can be raised successfully by a single parent as well as by a pair, with males able to compensate fully for the disappearance of the female after oviposition (Fetherston et al., 1994). Burying beetles therefore provide an uncommon example of extended, facultative biparental care in insects, of interest to entomologists, ecologists, and evolutionary biologists.

Putative Chemosignals of the Ferret (Mustela furo) Associated with Individual and Gender Recognition

Quantitative stir bar sorptive extraction methods, both in the aqueous and headspace modes, followed by thermal desorption gas chromatography-mass spectrometry were used to investigate individual variations in the volatile components of male and female ferret (Mustela furo) urine. The urinary profiles were further compared with volatile profiles of anal gland secretions of breeding male and female ferrets. Thirty volatile compounds were quantified in male and female urine. Among them, 2-methylquinoline was unique to male urine. Four ketones (4-heptanone, 2-heptanone, o-aminoacetophenone, and a dimethoxyacetophenone) and several nitrogen compounds (e.g., 2,5-dimethylpyrazine, quinoline, 4-methylquinazoline) and low levels of three unidentified nonsulfur compounds were significantly more abundant in males than in females. Quantitative comparison of 30 volatile urinary compounds showed several statistically significant differences between the sexes and individuals of the same sex. These findings suggest that ferrets may use urine marking for sex and individual recognitions. Ten of the 26 compounds identified in anal gland secretions from females and males were also found in urine. However, most of the major compounds (thietanes, dithiolanes, and indole) in anal glands were not present in urine. This suggests that urine may convey specific signals that differ from those of anal glands. Additionally, 10 volatiles (two aldehydes, five ketones, benzothiazole, 2-methylquinoline, and 4-methylquinazoline), not previously identified, were found in ferret anal gland secretions. Among the new compounds, o-aminoacetophenone was found only in males, while only traces of this compound were found in females. Similar results were previously obtained in anal glands of three other Mustela species. These findings provide new information about the constituents of urine and volatile components of anal gland secretions in ferrets.

Volatile Compounds from Anal Glands of the Wolverine, Gulo gulo

Dichloromethane extracts of wolverine (Gulo gulo, Mustelinae, Mustelidae) anal gland secretion were examined by gas chromatography-mass spectrometry. The secretion composition was complex and variable for the six samples examined: 123 compounds were detected in total, with the number per animal ranging from 45 to 71 compounds. Only six compounds were common to all extracts: 3-methylbutanoic acid, 2-methylbutanoic acid, phenylacetic acid, alpha-tocopherol, cholesterol, and a compound tentatively identified as 2-methyldecanoic acid. The highly odoriferous thietanes and dithiolanes found in anal gland secretions of some members of the Mustelinae [ferrets, mink, stoats, and weasels (Mustela spp.) and zorillas (Ictonyx spp.)] were not observed. The composition of the wolverine's anal gland secretion is similar to that of two other members of the Mustelinae, the pine and beech marten (Martes spp.).

Ferret odor as a processive stress model in rats: neurochemical, behavioral, and endocrine evidence.

Predator odors have been shown to elicit stress responses in rats. The present studies assessed the use of domestic ferret odor as a processive stress model. Plasma corticosterone and adrenocorticotropin hormone levels were higher after 30 min of exposure to ferret odor (fur/skin) but not control odors, ferret feces, urine, or anal gland secretions. Behavioral differences were also found between ferret and the control odors as tested in a defensive withdrawal paradigm. In addition, c-fos messenger RNA expression in several brain areas previously associated with processive stress was significantly higher in ferret odor-exposed rat brains than in control odor-exposed brains. These results suggest that ferret odor produces a reliable unconditioned stress response and may be useful as a processive stress model.

Detecting danger—or just another odorant? Olfactory sensitivity for the fox odor component 2,4,5-trimethylthiazoline in four species of mammals

2,4,5-trimethylthiazoline (TMT) is a volatile component of the anal gland secretion of the red fox and elicits behavioral and physiological fear responses in the rat. Using instrumental conditioning paradigms, we determined olfactory detection thresholds for TMT in three rats, a natural prey species of the red fox, and compared their performance to that of three squirrel monkeys, three spider monkeys and four pigtail macaques, all non-prey species of the red fox. We found that the rats were able to discriminate concentrations between 0.04 and 0.10 ppt (parts per trillion) of TMT from the odorless solvent which is by far the lowest olfactory detection threshold for an odorant reported in rats so far. In contrast, the spider monkeys needed 0.14–1.38 ppb (parts per billion), the pigtail macaques 0.41–4.07 ppb, and the squirrel monkeys 4.07–13.80 ppb to detect TMT which does not rank among the lowest olfactory thresholds reported for these three primate species. Thus, these results support the assumption that the behavioral relevance of an odorant may be an important determinant of a species' olfactory sensitivity.

SEXUAL DIMORPHISM IN THE DEVELOPMENT OF SCENT STRUCTURES FOR THE OBLIGATE MONOGAMOUS EURASIAN BEAVER (CASTOR FIBER)

Scent marking is a common form of territorial demarcation in mammals and differential marking by the sexes may select for differences in scent gland developmental rates or size. Rates of marking reflect level of defense and so behavioral dimorphism in marking by the sexes may select for dimorphism in scent structures. Eurasian beavers (Castor fiber) are monogamous, territorial mammals that show some behavioral dimorphism in territoriality. Beavers have 2 primary scent structures, anal glands and castor sacs. Anal gland secretion appears to serve as a family or individual identifier. Castor fluid is the main source of chemical signals used for marking territories. We examined beavers collected from 3 different habitats, namely streams, creeks and tarns (small lakes), which varied in the density of beaver sites. The objectives of this study were to examine if morphological attributes of Eurasian beaver scent structures reflected differences in adult beaver territorial function or in the ontogeny of the sexes. We hypothesized that male beavers would have larger castor sacs and anal glands, and that beavers from sites of greater density, and thus greater rates of intrusion, would have larger castor sacs and anal glands. Our results showed that investment did not differ by habitat type. Although the combined weight of the scent structures did not differ between the sexes, males developed significantly larger anal glands but somewhat smaller castor sacs than females. Total investment to scent structures may be limited but allocation is flexible. Males patrol the territory more extensively and may benefit by releasing anal gland secretion to signal their identity to potential intruders. Higher rates of marking may decrease castor sac size by reducing the amount of stored scent material. Hence, even in monogamous mammals, sexual dimorphism can arise from behavioral dimorphism.

Contribution of anal scent gland and urinary odorants to mate recognition in the ferret

Previous research [J. Neurosci. 21 (2001) 5832–5840] showed that ferrets of both sexes require olfactory signals to identify opposite-sex mating partners at a distance. The present experiments assessed the contributions of anal scent gland and urinary odorants to these preferences. Sexually experienced, ovohysterectomized female and castrated male ferrets were injected daily with estradiol benzoate and testosterone propionate, respectively. When tested in an airtight Y-maze, subjects of both sexes preferred to approach volatile odors emitted from opposite- versus same-sex stimulus ferrets that were anesthetized and placed in the goal boxes, regardless of whether the anal scent glands of stimulus ferrets had been surgically removed or left intact. Subjects of each sex showed an equal preference to approach volatile odors emitted from anesthetized opposite-sex ferrets that were scent-gland intact as opposed to descented. Female subjects preferred to approach volatile anal scent gland odorants, as well as urinary odorants from male, as opposed to female conspecifics. Male subjects preferred to approach volatile anal scents from females versus males; however, males showed no preference for female over male urinary odorants. Our results suggest that anal scent gland odorants are sufficient, but not required, for mate recognition in the ferret. Instead, a combination of body odorants including, but not restricted to, those derived from anal scent gland secretions apparently underlie olfactory sex discrimination and partner preference in this carnivore.

Subspecies discrimination in the Scandinavian beaver (Castor fiber): combining behavioral and chemical evidence

Geographic isolation is one of several models that has been proposed to explain the evolutionary course of speciation. In this study, we examined how geographical isolation may affect subspecies discrimination in the free-ranging Scandinavian beaver (Castor fiber fiber L., 1758) by simulating a territorial intrusion by using scent (castoreum and anal gland secretion) from a con-subspecific (N = 8 for castoreum and N = 7 for anal gland secretion) and a hetero-subspecific (Castor fiber albicus Matschie, 1907; N = 2 for both castoreum and anal gland secretion). Direct observations of 33 families during evenings showed that beavers (i) sniffed castoreum but not anal gland secretion from C. f. fiber significantly longer than from C. f. albicus and (ii) responded aggressively (i.e., stood on the mound on their hind feet, pawing and (or) overmarking) significantly longer to castoreum but not anal gland secretion from C. f. fiber than from C. f. albicus. When experimental scent mounds were allowed to remain overnight, the response was significantly stronger to castoreum but not to anal gland secretion from C. f. fiber than from C. f. albicus. Gas chromatographic comparisons of castoreum and anal gland secretion from the two subspecies supported our behavioral observations for castoreum but not for anal gland secretion. These findings suggest that geographical isolation has developed discriminatory abilities in C. f. fiber. We further suggest that the proximate factors involved are of environmental origin.

Effect of concentration of anal gland scent lures on the capture rate of ferrets (Mustela furo) in winter and spring

We tested scent lures made from the anal gland secretions of male and female ferrets (Mustela furo L.) at 0.1–2% concentration in “Albert”, a solid, long‐life, casein‐based formulation, as attractants for feral ferrets in winter and spring. Live traps at 10 study sites in Canterbury and Otago lured with 2% female scent caught significantly more ferrets (1.00 per 100 corrected trap nights) than those lured with a fish‐based paste (0 per 100 CTN), and at least twice as many as those lured with male scent or lower concentrations of female scent. The traps lured with the 2% female scent caught both male and female ferrets in approximately equal numbers, at a time of year when it is sometimes difficult to capture females. Capture rates of female ferrets increased with increasing female scent lure concentration, but this response was not shown by male ferrets, nor was it shown by either sex to increases in concentration of male scent lures. The results of this study have confirmed the findings of previous studies about the potential of ferret anal gland secretions as lures for ferrets. Further research is needed, using radio‐telemetry, to determine what proportion of the ferret population is attracted to these lures compared with traditional rabbit meat lures, and whether this varies seasonally.

Effects of sex hormones and gender on attraction thresholds for volatile anal scent gland odors in ferrets

Body odors contribute to mate recognition and sexual partner preference in many mammals, including ferrets. We used a habituation/dishabituation procedure to test whether sex steroid hormones influence whether ferrets will approach and investigate different concentrations of volatile anal scent gland odors from male and female conspecifics. When tested with high concentrations of anal scent gland secretions in oil vehicle, gonadectomized male and female ferrets that received no sex steroids reliably discriminated anal scents from male and female conspecifics. This discrimination most likely reflects gender recognition rather than individual recognition because gonadectomized, sex steroid-treated ferrets discriminated between anal scents of males and females but not between anal scents of individual males or females. Treatment with either the estrogen receptor agonist, estradiol benzoate (EB), or the androgen receptor agonist, 5-α dihydrotestosterone proprionate (DHTP), increased investigation of low concentrations of anal scent by gonadectomized ferrets. These data suggest that ferrets could use anal scent gland secretions in mate recognition and that seasonal increases in circulating sex steroid hormones increase ferrets' responsiveness to low concentrations of these odors.

Effects of weasel odor on behavior and physiology of two hamster species

This study examined the behavioral and physiological effects of long-term exposure to overdose of aversive odor (predator odor) in two species of hamsters. About 0.05 mg of anal gland secretions of Siberian weasels ( Mustela sibirica) was smeared at the oronasal groove of wild male ratlike hamsters ( Cricetulus triton) (natural prey) and laboratory golden hamsters ( Mesocricetus auratus) once every day for 4 weeks. After 28 days, the experimental groups of both hamster species displayed higher cortisol level, larger adrenal gland (in ratlike hamsters only), smaller thymus and flank gland, and lower aggression level than the conspecific control group (presented with water). Thus, the long-term presence of overdose of the anal gland secretion of the Siberian weasel could lower the aggression and social rank and suppress the immunity in the hamsters. The reproductive conditions of these prey species, however, seemed not to be affected. In addition, the similarities in the behavioral and physiological responses to the predator odor between the two species of hamsters showed that the responses to predator odor might be innate.

Possible coding for recognition of sexes, individuals and species in anal gland volatiles of Mustela eversmanni and M. sibirica.

With a combination of solvent extraction and gas chromatography-mass spectrometry, we found eight new compounds in the two sympatric Mustela species, M. eversmanni and M. sibirica. These compounds had not been detected by headspace sampling with solvent desorption. Two of the newly detected compounds are nitrogen-containing compounds, indole and o-aminoacetophenone and the remaining are sulfur-containing volatiles. By comparing same and opposite sexes between the two Mustela species, we found that qualitative differences in the anal gland secretion are most likely to be used to code for information about species, corresponding to the idea of digital coding. In the Siberian weasel (M. sibirica), both presence or absence of sex-specific compounds (Z-2-ethyl-3-methylthietane only in females) and relative abundance of some compounds between males and females could be used to code for information about sex, corresponding to the idea of digital and analog coding, respectively. In the steppe polecat (M. eversmanni), only quantitative differences provided the possibility for inter-sexual communication. Thus coding for information about sex appeared to be digital. Coding for individual information could also be either digital or analog or both through the presence or absence of certain compounds and/or the difference in the relative abundances of certain compounds among individuals. Comparing with other Mustela spp., we failed to find a congruence between the chemical composition of anal gland secretions and the phylogenetic relationship among the species in this genus.

Long-chain fatty acids in the anal gland of the red panda, Ailurus fulgens

1. Subjects and sourceThe red panda (Ailurus fulgen) is reddish brown, long-tailed mammal, found inthe mountain forests of the Himalayas and adjacent areas of eastern Asia, whichsubsists mainly on bamboo (Choudhury, 2001). This species as with most Carnivora,possesses paired anal glands used by both sexes to scent-mark. Red pandas emit amusky odor from these glands when excited (Nowak, 1991), and according to Rob-erts and Gittleman (1984) secretions from these anal glands, in addition to urine andfeces, are used to mark territories.2. Previous workThere are no previous reports on the composition of the anal gland secretions ofA. fulgen (family Ailuridae). This secretion has been analysed for other members ofthe Musteloidea, including the families Mephitidae (Wood, 1990; Wood et al., 1991;Wood et al., 1993; Wood et al., 2002), Procyonidae (Schildknecht and Ubl, 1985),and Mustelidae (Crump, 1980a; 1980b; Crump and Moors, 1985; Davies et al., 1988;

Odor-Induced Variation in Anxiety-Like Behavior in Mice is Associated with Discrete and Differential Effects on Mesocorticolimbic Cholecystokinin mRNA Expression

The present investigation assessed alterations in mesocorticolimbic cholecystokinin (CCK) mRNA following novel predator and non-predator odor exposure and light-dark testing in CD-1 mice. In brief, acute exposure of CD-1 mice to the predator odor, 2,5-dihydro-2, 4,5-trimethylthiazoline (TMT; the major component of the anal gland secretions of the red fox), or the control odor, butyric acid (BA), suppressed rearing behavior during odor presentation, subsequently induced anxiety in the light dark test, and was associated with increased mesocorticolimbic CCK mRNA relative to saline treated mice. Only mice exposed to TMT displayed elevated freezing behaviors during odor treatment. In the light-dark test, mice exposed to either BA or TMT took longer to reenter the light section of the apparatus and spent less cumulative time in the light relative to mice exposed to saline. The decreased time spent in the light as well as light dark transitions were exaggerated among mice exposed to fox odor. Odor presentation was associated with increased CCK mRNA in mesocorticolimbic sites. Butyric acid was associated with enhanced CCK gene expression in the VTA, while both BA and TMT were associated with increased medial prefrontal cortex (mPFC) CCK mRNA levels. Increased CCK mRNA within the VTA and mPFC was evident among mice despite testing in the light-dark box. In contrast, basolateral nucleus of the amygdala (BLA) CCK mRNA was enhanced following odor exposure among mice in the light dark test relative only to saline treated mice which demonstrated a natural decrease in BLA CCK mRNA following the light dark test. The differential pattern of CCK mRNA associated with discrete psychogenic stressor manipulations and the provocation of anxiety-like behavior associated with such experiences is discussed.

A test of the dear enemy phenomenon in the Eurasian beaver

We tested the hypothesis that Eurasian beavers, Castor fiber, display the dear enemy phenomenon; that is, they respond less aggressively to intrusions by their territorial neighbours than to intrusions by nonterritorial floaters (strangers). This ability could be advantageous in facilitating differential treatment of wandering strangers versus established neighbours. Territorial beavers were presented with scent from neighbouring and stranger adult males. Thirty-nine different active beaver families, 18 in 1998 and 21 in 1999, were presented with a two-way choice between two pairs of experimental scent mounds; mounds with castoreum from a neighbour and a stranger, and mounds with anal gland secretion from a neighbour and a stranger. Direct observations of the families during evenings showed that: (1) beavers sniffed both castoreum and anal gland secretion from a stranger significantly longer than from a neighbour, and (2) beavers responded aggressively (stood on the mound on their hind feet, pawing and/or overmarking) significantly longer to castoreum, but not to anal gland secretion, from a stranger than from a neighbour. When experimental scent mounds were allowed to remain overnight and the beavers' responses were measured the following morning, the beavers' responses were significantly stronger to both castoreum and anal gland secretion from a stranger than from a neighbour. These findings indicate that Eurasian beavers can use scent to discriminate between neighbours and strangers, thereby supporting existence of the dear enemy phenomenon in this species. Copyright 2002 The Association for the Study of Animal Behaviour. Published by Elsevier Science Ltd. All rights reserved.

Do Eurasian beavers smear their pelage with castoreum and anal gland secretion?

The scent-matching hypothesis postulates that scent marks provide an olfactory link between a resident owner and his territory, and that this enables intruding animals to recognize the chance of escalated conflicts. However, it is unclear if Eurasian beavers (Castor fiber) mark their own pelage with castoreum from their castor sacs (i.e., the same material used in territorial marking); and/or if beavers mark their pelage with anal gland secretion (AGS) from the anal glands to waterproof the pelage and to act as a "living-scent mark." Chemical analysis (gas chromatography and mass spectrometry) of hair samples from 22 live-trapped beavers revealed that castoreum compounds were not present in any samples, AGS compounds were found from 3 animals (13.6%) around the cloaca, and the compound squalene was found in all the samples. Beavers may release castoreum directly into the water when it meets an intruder. Thereby, the "scent mark" in the water can provide an olfactory link between a resident owner and his territory. Squalene, in contrast to AGS, may be essential for keeping beaver pelts water-repellant.

Volatile compounds in anal gland of Siberian weasels (Mustela sibirica) and steppe polecats (M. eversmanni).

The volatile constituents in anal gland secretions of two sympatric Mustela species, the Siberian weasel (M. sibirica) and steppe polecat (M. eversmanni), were studied by the headspace technique, followed by gas chromatography-mass spectrometry (GC-MS) analysis. Nine sulfur-containing compounds were identified. They were 2,2-dimethylthietane, (Z)- or (E)-2,4-dimethylthietane, (E)-2,3-dimethylthietane, 2-ethylthietane, (E)-2-ethyl-3-methylthietane, (Z)-2-ethyl-3-methylthietane, 2-propylthietane, 3,3-dimethyl-1,2-dithiacyclopentane, and (Z)-3,4-dimethyl-2,2-dithiacyclopentane. Among them, (E)-2-ethyl-3- methylthietanes, (Z)-2-ethyl-3-methylthietanes, and (Z)-3,4-dimethyl-1,2-dithiacyclopentane were present in the polecat but not in the weasel. The predominant compound was 2,2-dimethylthietane in the weasel and (E)- or (Z)-2,4-dimethylthietane in the polecat. These differences were consistent between the two species, regardless of sex and age and, therefore, could possibly be used for species recognition. In the weasel, 2-ethylthietane was found only in the female, and the relative abundance of several compounds was significantly different between males and females. In the polecat, although no sex-specific volatile compounds were found, males and females differed in the relative abundance of several of the compounds. In both species, the relative abundance of some compounds varied with age. We conclude that these volatile compounds can be used to communicate information about species, sex, and age.

Investigations of Waterborne Pathogens in Eurasian Beaver (Castor fiber) from Telemark County, Southeast Norway

The presence of pathogenic bacteria and parasites in drinking water is a well-known cause of human disease outbreaks [14,16]. There is however, a lack of knowledge of the contamination routes to water. In Norway, the supply of drinking water to the public and the food industry is primarily based on chlorinated surface water. Since the Eurasian beaver (Castor fiber) has a widespread distribution in southern Norway [18], and lives in water, it may excrete pathogens into drinking water sources. The present study was carried out to examine whether beaver in Norway might be a reservoir of parasites belonging to the protozoan genera Giardia and Cryprosporidium, or bacteria of the genera Campylobacter and Salmonella. Flagellates of the genus Giardia are common intestinal parasites of many mammals and are considered the most common cause of waterborne gastroenteritis in North America [7]. Giardia cysts are frequently found in Norwegian surface water sources [12] and the number of reported human cases of giardiasis is rising here [2]. In the USA, the prevalence of Giardia infection in beaver (C. canadensis) has been reported to be 7–16% [8] and the beaver is considered a potential health threat if inhabiting watersheds used as sources of drinking water [7]. The parasite is resistant to chlorination [17]. Cryptosporidium spp. are coccidian parasites causing intestinal infections in a wide range of mammals including man [19,24,29]. Cryprosporidium oocysts are frequently isolated from surface water sources in Norway [12] but the number of reported human cases of Cryptosporidiosis is low here [2]. The parasite is highly resistant to chlorination [9]. Cryptosporidium infection in beaver has been reported from Poland [4] and the USA [15]. Campylobacter spp. is the most common water and food-borne pathogen causing human enteritis in Norway [2]. The bacterium has been demonstrated in the intestinal contents of a wide variety of domestic and wild animal species [25] and is regularly isolated from river water in Telemark [26]. In Norway, human waterborne outbreaks have been traced to faecal contamination from gulls (Larus spp.), geese (Anser brachyrhynchus) and sheep [1,6,30]. [21] reported the absence of Campylobacter infection in 75 beavers examined in North America. Salmonella contamination and salmonellosis in humans and farm animals is an increasing problem in the industrialized countries [22]. In Norway however, Salmonella is a limited problem and most of the human clinical cases (80–90%) are infected abroad [5,11]. In spite of this, a waterborne outbreak of human S. typhimurium infection has been reported here [10]. Salmonella may infect a wide range of wild and domestic mammals and birds which may also act as carriers. Salmonella spp. have also been isolated from beavers in Germany and Russia [23]. Faecal samples were collected from beavers of different sex and age-classes living in the water systems of Bo, Sauherad and Nome municipalities (59° 17'–25'N, 09° 03'–17'E) in Telemark County, southeast Norway during the years 1997–1999 (Table ​(Table1).1). The animals were either live-trapped with landing nets [27], Hancock or Bailey live-traps, or shot during the hunting season (Table ​(Table1).1). The beavers were sexed by the colour of the anal gland secretion [28] or the presence of the os-penis [20] and partitioned into three age-classes based on body weight [13]: juveniles (≤ 12 months, 24 months, ≥ 15 kg). Table 1 The number of Eurasian beavers (Castor fiber) from Telemark County, Norway, analysed for the presence of the bacterias Campylobacter spp. and Salmonella spp., and the protozoens Giardia ... Campylobacter was isolated from faecal swab samples brought to the laboratory and streaked out onto a selective blood free agar [CCDA-modified Preston agar, Oxoid CM 739 and SR155 supplement] within 2 hours. The agar plates were incubated at 42°C in a micro aerobic athmosphere achieved by using the Oxoid, Campy Gen code CN025A and read after 24 and 48 hours. Salmonella was isolated by examining one gram of fresh or frozen faeces following the procedure described in NMKL 71 [3]. Giardia and Cryptosporidium detection. The ProSpectT® microplate assay for in-vitro diagnosis of Giardia and/or Cryptosporidium, Alexon inc., Sunnyvale, CA 94089, USA was used. Preliminary positive samples were followed up by individual assays. For confirmation of Giardia the ProSpectT® Giardia EZ microplate assay for in-vitro diagnosis of Giardia, Alexon-Trend, Inc Ramsey, MN 55303, USA was used. For confirmation of Cryptosporidium the ProSpecT® Cryptosporidium microplate assay, Alexon-Trend, Inc. Ramsey, MN 55303, USA was used. Neither Giardia, Cryptosporidium, Campylobacter nor Salmonella were detected in any of the samples examined. We conclude that the beaver does not seem to be involved in drinking water contamination with these pathogens in Telemark County.

Scent marking in Eurasian beaver Castor fiber during winter

The Eurasian beaver Castor fiber Linnaeus, 1758 deposit castor fluid (castoreum) and/or anal gland secretion at scent mounds in their territory year round.

Eurasian beavers (Castor fiber) behavioral response to simulated territorial intruders

Eurasian beavers (Castor fiber) live in family groups that defend territories against other conspecifics. Part of this territorial defence involves constructing scent mounds near the stream bank within territories and marking them with castoreum, a urine-based fluid from the castor sacs, and (or) anal-gland secretion. The aim of this study was to test the hypothesis that Eurasian beavers show one or more forms of territorial behavior when an intruder, simulated in the form of experimental scent mounds (ESMs), has scent-marked inside the territory. We predicted that beavers would show a stronger response to ESMs with castoreum than to those without. Results showed that 85% of all beaver families (N = 20) made one or more behavioral responses to ESMs marked with castoreum from foreign adult males, whereas no ESMs presented without castoreum received a response. We therefore conclude that a main function of territorial marking by beavers is to advertise spatially related dominance status, thereby providing opportunities for intruders to assess the presence of the owner and reducing the cost and risks of agonistic conflict for both the owner and intruders. Additionally, it appears to be the scent emitted from an ESM and not the sight of it to which beavers respond.