Territorial Scent Marking Research Articles

Territorial scent-marking and proestrus in a recolonizing wild Gray Wolf (<i>Canis lupus</i>) population in central Wisconsin

Gray Wolf (Canis lupus) uses scent-marking to communicate breeding status, dominance, and territorial boundaries. Despite its importance for reproduction and pack dynamics, information on scent-marking and proestrus in wild wolf populations is limited to a handful of locations. We estimated the rate of territorial scent-marking and the probability of proestrus in a recolonizing Gray Wolf population near the species southern range extent in eastern North America. An analysis of 221 pack-winters of tracking data show that the incremental addition of one wolf pack increased marking rates by 3.4%, whereas increasing the number of wolves in a pack decreased marking rates by 12.1%. Scent-marking rates subsequently increased from 1.9 times/km during recolonization to 3.0 times/km once the population was saturated. We observed evidence of proestrus from 19 December to 14 March with the highest probability of proestrus occurring around 6 February, after peak marking rates around 26 January. Repeated observations of bloody urinations within individual packs suggest proestrus averages 27.9 days. Our study reveals the role of population growth on territorial behaviours and provides a foundation for studies exploring the role of geographic and temporal variation on territorial and reproductive behaviours in wolves.

Extended and cumulative effects of experimentally induced intergroup conflict in a cooperatively breeding mammal

Conflict between rival groups is rife in nature. While recent work has begun exploring the behavioural consequences of this intergroup conflict, studies have primarily considered just the 1–2 h immediately after single interactions with rivals or their cues. Using a habituated population of wild dwarf mongooses (Helogale parvula), we conducted week-long manipulations to investigate longer-term impacts of intergroup conflict. Compared to a single presentation of control herbivore faeces, one rival-group faecal presentation (simulating a territorial intrusion) resulted in more within-group grooming the following day, beyond the likely period of conflict-induced stress. Repeated presentations of outsider cues led to further changes in baseline behaviour by the end of the week: compared to control weeks, mongooses spent less time foraging and foraged closer to their groupmates, even when there had been no recent simulated intrusion. Moreover, there was more baseline territorial scent-marking and a higher likelihood of group fissioning in intrusion weeks. Consequently, individuals gained less body mass at the end of weeks with repeated simulated intrusions. Our experimental findings provide evidence for longer-term, extended and cumulative, effects of an elevated intergroup threat, which may lead to fitness consequences and underpin this powerful selective pressure.

Involvement of serotonin and oxytocin in neural mechanism regulating amicable social signal in male mice: Implication for impaired recognition of amicable cues in BALB/c strain.

Social signals play a primary role in regulating social relationships among male mice. The present series of experiments investigated the neural mechanisms underlying an induction of amicable cues that facilitate social approach in male mice of the C57BL/6 (B6) and BALB/c (BALB) strains. Male mice exhibit approach behavior and suppression of territorial scent marking toward amicable counterparts. Exposure of a group-housed mouse that maintains an amicable relationship induced social approach in B6 recipient mice, as expressed by increased preference of stay in proximity and decreased scent marks relevant to those of a single-housed mouse. Nasal administration of oxytocin (OT) to stimulus mice appeared to enhance social approach in B6 recipient mice. Systemic administration of buspirone (5-HT1A agonist) to stimulus mice also increased approach in B6 recipient mice, whereas a nasal OT antagonist infusion followed by systemic buspirone injection of stimulus mice blocked this buspirone-induced approach in B6 recipient mice. BALB mice likely possess an intact signaling system as shown in B6 mice, in which the 5-HT → OT pathway is a primary modulator for social amicable signals. However, BALB mice could not exhibit signal-dependent change in approach behavior. No impairment in olfactory discrimination or approach behavior toward social stimuli was found in BALB mice. It is concluded that social cues for facilitating social approach are eliminated via the 5-HT → OT pathway, and BALB mice as a low social strain have a deficit in recognition of specific signals associated with amicability. (PsycINFO Database Record

In Space and Time: Territorial Animals are Attracted to Conspecific Chemical Cues.

Territorial animals lay scent marks around their territories to broadcast their presence, but these olfactory signals can both attract and repel con-specifics. Attraction or aversion can have a profound impact in terms of space use and thereby influence an individual's access to resources and mates. Here, we test the impact of chemical signals on the long-term space use and activity of receivers, comparing the response of males and females, territory holders, and temporary visitors in Sceloporus undulatus lizards in the field. We placed either male femoral gland secretions (chemical) or blank (control) cues on resident male landmarks, repeatedly over 5 d, while monitoring the activity and location of all lizards in the vicinity. We found that resident males and females, but not non-resident males, were active on more days near landmarks treated with chemical cues than landmarks treated with control cues. Non-resident males remained closer to chemical than control cues. These results suggest that territorial scent marks are attractive to conspecifics and impact space use, but that the specific effects depend on receiver sex and residency status. Such subtle or gradual changes in behavior may frequently be overlooked by short-term choice experiments. Future studies investigating the behavioral significance of a communicative signal should consider these finer details of behavior for a more comprehensive assessment.

Will Trespassers Be Prosecuted or Assessed According to Their Merits? A Consilient Interpretation of Territoriality in a Group-Living Carnivore, the European Badger (Meles meles).

Socio-spatial interactions of Carnivores have traditionally been described using the vocabulary of territoriality and aggression, with scent marks interpreted as ‘scent fences’. Here, we investigate the role of olfactory signals in assumed territorial marking of group-living solitary foragers using European badgers Meles meles as a model. We presented anal gland secretions (n = 351) from known individuals to identifiable recipients (n = 187), to assess response-variation according to familiarity (own-group, neighbours, strangers) and spatial context (in-context: at a shared border; out-of-context: at an unshared border/ the main sett). Sniffing and over-marking (with subcaudal gland secretion) responses were strongest to anal gland secretions from strangers, intermediate to neighbouring-group and weakest to own-group members. Secretions from both, strangers and neighbours, were sniffed for longer than were own-group samples, although neighbour-secretion presented out-of-context evoked no greater interest than in-context. On an individual level, responses were further moderated by the relevance of individual-specific donor information encoded in the secretion, as it related to the physiological state of the responder. There was a trend bordering on significance for males to sniff for longer than did females, but without sex-related differences in the frequency of subcaudal over-marking responses, and males over-marked oestrous female secretions more than non-oestrous females. There were no age-class related differences in sniff-duration or in over-marking. Evaluating these results in the context of the Familiarity hypothesis, the Threat-level hypothesis, and the Individual advertisement hypothesis evidences that interpretations of territorial scent-marks depicting rigid and potentially agonistic discrimination between own- and foreign-group conspecifics are overly simplistic. We use our findings to advance conceptual understanding of badger socio-spatial ecology, and the general context of territoriality and group-range dynamics.

Central oxytocin regulates social familiarity and scent marking behavior that involves amicable odor signals between male mice

The effect of oxytocin on social behavior and odor communication was investigated in male C57BL/6J mice. In three-male colonies, in visible burrow systems, icv oxytocin (OT) infusion before colony formation substantially increased huddling together over the initial 8h of grouping, accompanied by decreased expression of a number of social approaches associated with conspecific aggression and defense. OT antagonist infusion had little impact on expression of social approaches but decreased time engaging in social components including huddle over the initial 8h. These results demonstrate a linkage of social familiarity to OT availability in the brain. In a scent marking paradigm central infusion of OT reduced territorial marking towards male conspecifics, and this in turn reduced the scent marking of untreated stimulus males to OT-infused subjects. Infusion of an OT antagonist into stimulus mice who were confronted with OT-infused subjects prevented the reduction/suppression of scent marking that was normally seen following exposure of social odors released from OT-injected mice. Odor of pair-housed mice also induced a suppression of territorial scent marking in odor recipients, but OT antagonist administration into pair-housed mice blocked this suppressive effect of odor cue. These results indicate that central OT modulates release as well as detection of amicable signals facilitating/maintaining familiar relationships and suppressing territorial behavior between male mice. Overall, these findings suggest that OT plays a significant role in regulating social familiarity via changing qualities of conspecific odor cues.

Basic emotional foundations of social dominance in relation to Panksepp's affective taxonomy

An examination of the chemistries and subcortical substrates of social “dominance” behavior has not been systematically reviewed in relation to the primary emotion circuitries described by Panksepp. This is a necessary first step toward untangling the affective foundations of social dominance, in order to determine whether it may legitimately be considered a discrete basic emotion. In this review, several classes of behavior are identified as potential expressions of dominance. They include intermale fighting, intimidation displays, and territorial scent marking. A review of the neurobiological evidence suggests a locus of control of dominance behaviors in a region defined by high density of testosterone and vasopressin (AVP) receptors surrounding the anterior hypothalamus. While many studies report findings regarding the elicitation of dominance behaviors from direct stimulation of these subcortical sites, there is nonetheless a great deal of inconsistency within the literature, as well as overlap with other basic emotion circuitries, making the identification of a consistently recognizable subcortical circuit across species a great challenge. Furthermore, the chemical control of dominance is probably more diverse than previously thought. Testosterone and AVP do not appear to be exclusively involved in dominance. These hormones regulate a variety of social behaviors linked to socio-sexual functioning. In light of these observations, it is unlikely that the coherence observed in the dominance phenotype is attributable to a distinct affective circuit, but it may instead reflect an interaction of several basic emotions operating together as a result of favorable outcomes during social development.

Secretions of pre-anal glands of house-dwelling geckos (Family: Gekkonidae) contain monoglycerides and 1,3-alkanediol. A comparative chemical ecology study

Abstract Squamate reptiles sense chemical stimuli carrying information about several biological properties of the sender. Despite the fact that sex recognition is often based on colour signals, such pheromone communication occurs in many species of lizards. Epidermal gland secretions of reptiles can have pheromone properties and might play an important role in sexual signalling and territorial scent marking. The house-dwelling geckos Hemidactylus turcicus , Hemidactylus flaviviridis , and Cyrtopodion scabrum are good examples of geckos having pre-anal glands in males only. We used GC–MS chemical analysis of gland secretions, compared secretions of different species, and compared secretions from two populations of H. turcicus . Surprisingly, we detected monoglycerides of fatty acids, and one 1,3-alkanediol. These compounds have been detected once before in reptiles. In addition, carboxylic acids, alcohols, steroids, alkanes, amides, one aldehyde, carboxylic acid esters, hydrocarbons, and squalene occurred. Polyol glycerol seems to play a role in the composition of the secretions probably as an adhesive of some kind for the secretion as a whole. The data supports our hypothesis that geckos can potentially use femoral gland secretions in chemical communication. Further studies are needed to test activities of these compounds in behavioural assays to eventually identify their possible role in communication.

Potential amplification of territorial advertisement markings by black-backed jackals (Canis mesomelas)

AbstractOptimality theory suggests that territorial scent marks are under selective pressure through the information they provide about competitive quality/reproductive status and so should be situated to maximize their detection to alert conspecifics that they are intruding upon the territory of a resident. Factors that increase mark detectability are consequently beneficial to both resident and intruder by allowing tactical withdrawal by intruders and, thus, reducing the costs of conflict. We tested whether black-backed jackals (Canis mesomelas) preferentially deposited territory marks on substrates (rocks or faeces) in two separate sites in South Africa's Addo Elephant National Park. Elephant (Loxodonta africana) dung piles were preferentially defecated upon by jackals in both sites. Where black rhinoceros (Diceros bicornis) was present at relatively high density, rhino middens were also preferentially marked by jackals; however, jackals resorted to defecating on elevated surfaces, such as rocks, where rhinos were scarce. We hypothesize that the odour of elephant and rhino dung may increase the detectability of jackal markings while providing an additional olfactory signal component, while rocks and elephant dung provide visual amplification. Manipulative experimentation will be necessary to confirm our multimodal amplification hypothesis.

Social features of scent-donor mice modulate scent marking of C57BL/6J recipient males

Territorial male mice can form familiarity-dependent amicable relationships, suggesting that they manage their territorial aggressiveness based on individual recognition, which may be mediated by olfactory signals. The present study demonstrated modulatory effect of odorant cues from mice of different social/housing groups on territorial scent marking by C57BL/6J males. Pair-housed males deposited few scent marks in a novel situation without mouse odors, while singly-housed males marked more in the same situation (Experiment 1). However, when confronted by a conspecific, singly-housed males made fewer marks to pair-housed than to singly-housed stimulus males, while pair-housed males showed few marks to either stimulus animal (Experiment 2). Reduction in scent marking in singly-housed males was also seen on exposure to urine scent alone from a pair-housed male, indicating that the inhibitory cue is mediated by urinary odor (Experiment 3). This inhibitory odor was effective even when singly-housed males were placed in a no-odor environment following exposure to soiled bedding used by pair-housed males (Experiment 4). When singly-housed males were exposed to scent from subordinate males, they showed less marking than when the stimulus scent was from dominants or singly-housed males (Experiment 5). Scent marking was not influenced by the total amount of urine scent marks deposited on the substrates (Experiment 6), suggesting that it is a particular component in urinary odor rather than the magnitude of the odor, that plays a significant role in recipient behavior. Together, these experiments indicate that conspecific male odor signals modulate territorial scent marking behavior in mice.

Restricted ranging behaviour in a high‐density population of urban badgers

AbstractBy studying the responses of different species to urbanization, it is possible to understand the impact of this type of habitat modification and to explore, more generally, the link between variations in the environment and changes in behaviour. We radio collared 17 badgers Meles meles from six social groups in a 1 km2 urban study area in Brighton, UK, where local badger population density was high, and collected data on their ranging behaviour between 2005 and 2007. We aimed to determine how badgers adapt their behaviour to an urban environment and to assess the generality of previously reported differences in the ranging and territorial behaviour of urban and rural badgers. Analysis of habitat preferences and movement patterns suggested that garden habitat was principally used for foraging, while scrub and allotment habitats were important in allowing animals to travel from one part of their range to another. Group and individual home ranges were the smallest so far recorded for badgers (mean 100% minimum convex polygons=9.26 and 4.91 ha, respectively). Individual range size was negatively correlated with the availability of garden habitat, suggesting that the rich food resources provided by gardens enabled ranges to be small. Group ranges were mostly non‐contiguous and there was no evidence of territorial scent marking; rather, activity was mainly restricted to areas in the vicinity of main setts. It is clear that badgers can adapt successfully to urban habitats and that this process affects various aspects of their behaviour. However, our high‐density population of urban badgers displayed patterns of behaviour that differed not only from those of typical rural badgers, but also in some respects from those of a previously studied low‐density urban population. We conclude that generalizations about the effects of urbanization must be made with caution.

Sexual Dimorphism in Territorial Scent Marking by Adult Eurasian Beavers (Castor fiber)

Mammalian scent marking is often associated with territorial defense. However, males and females may demonstrate different activity patterns and play different roles. Female mammals nurture the young during lactation, while males purportedly perform other tasks more frequently, such as territorial maintenance and defense. This paper investigates the contribution made by mated pairs of adult males and females to territorial scent-marking in the obligate monogamous Eurasian beavers (Castor fiber). We hypothesized that both sexes should show territorial behavior, and predicted that they deposit a higher proportion of scent marks at borders. We also hypothesized that a sexual dimorphism exists due to reproductive constraints on the females, and predicted that males should invest significantly more in scent-marking behavior than females during summer. We obtained behavioral data by radio tracking six mated pairs of Eurasian beavers during spring and summer 2000-2001 on two rivers in southeastern Norway. Our results showed that both males and females clustered their scent marks near territorial borders, but males deposited a larger number of scent marks than females and spent more time at borders. Males were also found to have a higher scent marking rate and scent marks per night than females during summer, but not during spring. Overall, scent marks per night were higher in males than females. We conclude that both males and females Eurasian beavers carry out territorial behavior by scent marking, but males carry a larger part of the territorial defense during summer when females lactate. Our results are discussed in the light of the codefense hypothesis.

Effects of vomeronasal organ removal on olfactory sex discrimination and odor preferences of female ferrets.

Previous research suggests that body odorants, including anal scents and urinary odors, contribute to sex discrimination and mate identification in European ferrets of both sexes. We assessed the possible role of the vomeronasal organ (VNO) in these functions by surgically removing the organ bilaterally in sexually experienced female ferrets. Lesioned (VNOx) and sham-operated control (VNOi) females reliably discriminated between male- and female-derived anal scent gland as well as fresh urinary odors in habituation/dishabituation tests. However, VNOi females spent significantly more time than VNOx subjects investigating male urinary odors in these tests. Also, VNOi females, but not VNOx subjects, preferred to investigate day-old male versus female urine spots as well as wooden blocks that had previously been soiled by male versus female ferrets. Both groups of female ferrets preferred to approach volatile odors from a breeding male instead of an estrous female in Y-maze tests and both groups showed similar levels of receptive sexual behavior in response to a male's neck grip. The VNO is apparently not required for olfactory sex discrimination or mate recognition in this carnivore, but instead may play a role in promoting continued contact with nonvolatile body odors previously deposited by opposite-sex conspecifics during territorial scent marking.

Competitor Assessment and Area Defense by Territorial Salamanders

viously marked by a nonresident conspecific male. We found that intruders approached residents in both conditions, that residents resorted to significantly more threat behavior and significantly more nose-tapping (scent-mark sampling) in condition 1, and that intruders significantly increased their rates of gular pumping (sampling air-borne odors?) in condition 1. From the results of this and previous experiments, we pose a preliminary hypothesis for the function of territorial scent marks by P. cinereus. Such scent marks have little effect on repelling or intimidating intruders. They are important to the resident in identifying his defended area, provide information to intruders about the status (e.g., size) of the resident, and probably allow the intruder to identify correctly the resident (as compared to other simultaneous intruders). Thus, scent marking appears to function primarily in providing information to both resident and intruder that can be used in their decisions con

Salamander scent marks: site of production and their role in territorial defence

Abstract. Male red-backed salamanders, Plethodon cinereus, were used to test the hypothesis that the post-cloacal gland produces scents for territorial marking. Experiment 1 tested the reaction of intruders to substrates marked with the products of the post-cloacal gland, those of the granular glands from the thoracic region (sham control), and unmarked substrates. To ensure that only certain glands were capable of marking substrates, glands were blocked by applying a synthetic bilayer. Intruders preferred substrates marked by previous residents with products of the post-cloacal gland and granular glands of the thoracic region over substrates that had not been marked. In experiment 2, observations were made of the interactions of intruders and residents when intruders were introduced into the residents' areas. Residents were blocked so that their substrates could only be marked with products of either the post-cloacal gland or the granular glands from the thoracic region. Residents spent more time in aggressive postures in trials where they had marked the substrate with the products of the post-cloacal gland compared with trials in which they had marked the substrate with products of the granular glands of the thoracic region. In addition, intruders initiated contact for longer periods than residents in both types of trials. The results of these two experiments suggest that the post-cloacal gland produces territorial scent marks and that scent marks do not cause avoidance by conspecifics.

Prenatal lead exposure in the rat during the third week of gestation: Long-term behavioral, physiological, and anatomical effects associated with reproduction

Sprague-Dawley dams were administered lead acetate (0.1%) in their drinking water from Day 14 of gestation to parturition to determine whether exposure of the fetus to elevated lead (Pb) levels during a period of rapid differentiation of the hypothalamic-pituitary-gonadal (HPG) axis would disrupt HPG function in adulthood. At birth, offspring from 20 Pb-treated and 10 control dams were weighed and 2 litter representatives from each sex were fostered to untreated dams. Animals were weaned at 26 days of age and subsequently group housed by sex and treatment. Blood Pb levels in prenatally exposed pups were below the limits of detectability at weaning. Female offspring from Pb-treated dams were found to have a significant delay in the day of vaginal opening. In a sample of lead exposed females, 50% were found to exhibit prolonged and irregular periods of diestrous which was accompanied by an absence of observable corpora lutea when they were euthanized at 83 days of age. Male offspring from these dams were found to have decreased sperm counts at 70 and 160 days of age and to exhibit significantly less territorial scent marking and masculine sex behavior in adulthood compared to controls. Azoospermia was observed in 1 lead exposed animal at 70 days of age and 2 animals at 160 days. Enlarged prostates were observed in Pb-exposed males measured at 160 days, but other sex organ weights were normal. Volume of the sexually dimorphic nucleus of the preoptic area of the hypothalamus in adulthood was significantly reduced by approximately 35% in Pb-exposed males. Pulsatile release of gonadotropins, measured in castrated adult animals of both sexes, revealed irregular release patterns of both FSH and LH in some Pb animals which were not observed in controls. The overall pattern of results suggests that multiple levels of the HPG axis can be affected by exposure to Pb during a period of gestation when structures related to the HPG axis are undergoing rapid proliferation. These data indicate that lead exposure during this period places the exposed animal at significant risk for reduced reproductive capacity in adulthood.

Are the analgesic effects of social defeat mediated by benzodiazepine receptors?

Social conflict in mice is associated with at least two forms of analgesia. A long-lasting opioid reaction is evident in intruder mice exposed to prolonged attack, whilst an acute non-opioid analgesia is seen in response to either defeat experience per se or the territorial scent-marking of an aggressive conspecific. Recent work from this laboratory has suggested that the non-opioid analgesic reaction to defeat experience may be mediated via benzodiazepine receptor mechanisms. The present studies were designed to further test this tentative hypothesis. Results confirmed that defeat analgesia is dose-dependently blocked by Ro15-1788 (20–40 mg/kg) and diazepam (2–4 mg/kg), and also indicated partial antagonism of the reaction by CGS8216 (2.5 mg/kg). The partial agonists CGS9896 (2.5–20 mg/kg) and ZK91296 (2.5–20 mg/kg) were ineffective in blocking the reaction, a finding also obtained with the full agonist ZK93423 (0.05–10 mg/kg). However, the antagonist/weak inverse agonist ZK93426 was found to possess significant intrinsic analgesic activity (10 mg/kg) and to enhance defeat analgesia (5–10 mg/kg). Although several interpretative frameworks for the current pharmacological profile are considered, it is concluded that full clarification of the substrates of defeat analgesia must await further investigations.

Habituation to territorial scent marks in the field by Lemur catta

Ring-tailed lemurs ( Lemur catta ) were studied in a forest reserve of Berenty, Madagascar. The focus male showed a greater sniffing and scent-marking response to branches marked with the scent of lemurs from other troops than to unmarked branches. The response to any one branch habituated over a period of days. The habituation was not a function of aging of the scent but was clearly position-specific; a high response could again be elicited by moving the same branch. Since the scent marks are often associated with aggressive interactions and are potentially useful for territorial demarcation, it is suggested that this habituation may function to reduce aggression at territorial boundaries.

Suppression of reproduction in water-deprived mongolian gerbils (Meriones unguiculatus).

The effects of water deprivation on reproduction and territorial scent marking in the Mongolian gerbil were studied. It was found that water deprivation produced no long-term effects on body weight in the gerbils but it did completely stop reproduction when both members of a pair or when only the female were deprived. Water deprivation did reduce the size of the males testis seminal vesicle and ventral scent gland size but reproduction did continue when only the male was deprived. When water was provided again reproductive function was recovered. It is concluded from these results that seasonal variations in water consumption may regulate seasonal breeding patterns in the wild gerbil population and that the access to a limited supply of water may be related to territoriality in the Mongolian gerbil.

Steroid regulation of territorial scent marking in the Mongolian gerbil ( Meriones unguiculatus)

Mongolian gerbils ( Meriones unguiculatus) display a territorial scent marking response associated with a ventral sebaceous gland. In males, both the gland and behavior are androgen dependent and hormone control of marking is delimited to the preoptic area. The present study examines the effects of eleven steroids, injected subcutaneously or implanted into the preoptic area, on territorial marking in adult male castrates. Steroid effects on ventral gland function are also described. The neural target cells that mediate marking respond to a narrower range of steroids than do peripheral target cells in the ventral gland. Testosterone appears to be the only endogenous steroid capable of eliciting marking in males. Other steroids which share molecular commonalities with testosterone (a 17β-hydroxyl group and a double bond involving carbon 4) also induce marking behavior. Central receptors may recognize the relevant endogenous steroid, testosterone, by these features.