Wolf scent marking with raised-leg urination

Raised-leg urinations were performed almost exclusively by dominant male and female wolves (Canis lupus). The alpha male and female in two captive groups showed full raised-leg urinations (RLUs) throughout the year. Each alpha male and female sniffed and marked on one another's marks frequently; however, the pair that bred did more marking and more double marking. They increased their marking frequency prior to and during the breeding season, decreased it at the time of parturition, while the female was in the den, and then increased to a moderate level when the female took part in pack activities again. Because the alpha pair was the principal sender and receiver of the message within the group, it is likely that double marks function to maintain and advertise the pair bond. Because the group that did not breed also did not double mark frequently, the presence of double marking in a captive group may be diagnostic of the viability of the group as a pack.     

The role of scent marking in Lemur catta agonistic behavior

Certain forms of marking behavior in Lemur catta have been considered to be aggressive in nature but had not been analyzed specifically in this respect. This study examines the relationship between the occurrence of all forms of marking behavior displayed by a captive group of lemurs and their physical and nonphysical aggressive interactions. All forms of marking behavior, especially males' tail mark and tail wave displays, were found to correlate with aggressive behavior including female-instigated agonism. In comparison, allogrooming, a behavior thought not to have an agonistic component, was not significantly correlated with any marking nor agonistic category. The data suggest that in intersexual interactions male marking behavior is an aggressive but nonphysical substitute for physical aggression toward females who have generally been regarded as dominant to males in this species.     

Raccoon dog scent marking by scats and its significance in social behaviour

Utilization pattern of latrines by raccoon dogs,Nyctereutes procyonoides viverrinus, was studied on a small island in western Kyushu, Japan. Seventy-eight latrines were spread over the study areas, these were mainly formed on the flat surface in woody areas. Although the site and number of latrines were fairly stable throughout the year, distribution of the utilized latrines and number of scats per latrine were changed seasonally. Latrines were grouped into several clusters and communal utilization of latrines by several animals was observed within the cluster. Seasonal changes of utilization pattern observed in communal utilization rate and cluster formation was assumed to be caused by the changing of the social unit of raccoon dogs. Familiarization within the home range and information site to conspecifics may be concluded as the function of latrines.     

Chemical scent constituents in feces of wild Iberian wolves (Canis lupus signatus)

In spite of the importance of feces in scent marking and intraspecific chemical communication of many mammals, only a few studies have examined the chemical constituents of feces that could have a signaling function. We described here the chemicals found in feces recently deposited in the wild by adult and pup Iberian wolves (Canis lupus signatus). By means of analyses using gas chromatography–mass spectrometry (GC–MS), we identified 77 compounds in feces of adult wolves, mainly heterocyclic aromatic organic compounds, such as indole or phenol, but also steroids, such as cholesterol, carboxylic acids and their esters between n-C₃ and n-C₁₈, aldehydes, alcohols and significant quantities of squalene and α-tocopherol, which would increase the chemical stability of feces on humid substrates. Some of the odoriferous compounds are very likely originated in the anal-sac secretions, and later incorporated onto feces during defecation. However, the abundance of the main odoriferous compounds in feces could be explained by the result of the bacterial action on food components. Feces of pups only had 26 compounds, most of these were also found in adults’ feces, but four compounds were only found in pups’ feces, and there were also age-related differences respect to the proportions of shared chemicals. These differences could be partly due to the absence of anal-sac glands in pups, which would not need to scent mark substrates.     

Olfactory preferences, scent marking, and "proceptivity" in female hamsters

Two appetitive sexual behaviors of female hamsters, attraction to odors of males and vaginal scent marking, were investigated and the correlations of each to reproductive states were determined. Both estrous and diestrous females were more attracted to the odors of intact males than to the odors of females or castrated males; this differential attraction was more pronounced for estrous females. Lactating females, but not pregnant females, were also preferentially attracted to odors of intact males. Thus, odors alone provided sufficient information to allow sexual discrimination by females, and estrous, diestrous, and lactating females were preferentially attracted to odors of intact males whereas pregnant females were not. Reproductive condition had no influence on responses to odors of castrated males or diestrous females. Vaginal scent marking was strongly influenced by reproductive state: Marking frequency was low in estrous, pregnant, and early lactation females, but high in late lactation and diestrous females, suggesting a function of advertisement of approaching receptivity. Thus sexual preferences based on olfactory cues and vaginal scent-marking frequency differed in their relationships to reproductive conditions. It is suggested that in other species such relationships between appetitive sexual behaviors and reproductive condition will depend on the species social organization, ecological niche, and taxonomic group, and consequently that the concept of preceptive behaviors should be broadened to include all appetitive sexual behaviors of females, not just those that are correlated with the hormonal state characterizing estrus.     

Habitat modification when scent marking: shrub clearance by roe deer bucks

Marking activities in many ungulate species involve some aggression directed towards the vegetation which usually affects the understorey layer. Roe deer bucks (Capreolus capreolus) usually defend mating territories within the forest, where they mark the vegetation and the ground by using chemical signals which are typically associated with the visual ones used. Here we describe the presence of roe-made clearings of about 2700 m² average size which contained a clump of marks. Roe bucks affected the vegetation mainly by means of fraying and scratching with antlers around the stem of bushes, and defoliation by leaf-biting. The analysis of these activities suggests that their evolution may have been moulded by the effect of shrub clearing. Defoliation affecting more than 50% of leaves was only found within clearings. Also, fraying affected the whole perimeter of the stem and hence desiccated the bushes at higher rates within the clearings than outside. We found only one cleared area per male range, selectively located in a concave land formation. Producing a clump of scent marks within the mating territory may reduce the costs of scent marking, improve the effectiveness of scent guarding and fits well with the hypothesis of reliable scent matching by recipients. The concave shape of the clump, coupled with the cleared vegetation, may improve the perception of visual signals allowing for the location of scents. It is proposed that selection may favour the modification of the habitat as a component of roe deer marking behaviour, via its benefits in improving the broadcasting of visual signals associated with chemical ones.     

Hormonal control of precopulatory sebaceous scent marking and ultrasonic mating vocalizations in male rats

The effects of testosterone (T) and its major metabolites, estradiol (E2) and dihydrotestosterone (DHT), on the restoration of sebaceous scent marking and 50-kHz ultrasonic vocalizations in male rats were measured in two studies (Experiments 1 and 2) employing different hormone levels. Silastic capsule administration of high and low doses of T (10 and 20 mm) or E2 (5%; 5 and 10 mm) completely restored marking to precastration levels. Both doses of DHT (30 and 40 mm) or no hormone replacement were without effect when tested in presence of estrous odor cues. In our testing paradigm, males appeared to mark glass objects with a sebaceous secretion rather than urine. Only the high dose of T (20 mm) restored vocalizations to intact levels, while animals receiving the high or low dose of E2 or DHT showed no restoration of behavior. In Experiment 3, habituation to estrous odor cues over weekly tests was not observed for marking or vocalizations. These results are discussed with respect to similarities and differences in the hormonal control of signaling behaviors by androgen metabolites in male rodents.     

Female prairie voles do not choose males based on their frequency of scent marking

We conducted an experiment to test three alternative hypotheses for the function of frequency of scent marking in male prairie voles, MICROTUS OCHROGASTER: (1) sexual attraction (to advertise male quality for mating); (2) reproductive competition; and (3) self-advertisement or individual identity. In laboratory experiments, males deposited scent on all areas of a bare substrate, and more in an area next to a stimulus animal than other areas, regardless of the stimulus animal's sex. Females did not choose mates based on their frequency of scent marking and scent marking did not antagonize or stimulate aggression between males. The frequency of scent marking by males supports the individual identity hypothesis, and is less consistent with the sexual attraction or reproductive competition hypotheses. Mate choice is likely based on a complex suite of characters, but at least in prairie voles, the frequency of scent marking by males does not appear to be one of them.     

Behavioural responses of desert gerbil, Meriones hurrianae after removal of scent marking gland

The desert gerbil, M. hurrianae scent marks the general substratum in its territory with the sebum exudation of mid abdominal gland and urine. Having assessed number of functions, which scent marking plays in the social life of these rodents, the scent marking behaviour was studied in animals, in which the gland was surgically removed and was compared with that of intact rodents. After recovery from the operation, the scent marking frequency of both male and female M. hurrianae declined significantly and was maintained at a low level. Surprisingly, scent marking with urine also declined considerable with time. After 5 months of the operation, desert gerbils were given a choice to respond to male and female sebum odours. The frequency of their scent marking with either sebum or urine did not show any significant enhancement as compared to their initial marking rate. However, the duration of their stay and scent marking frequency near the source of the sebum odour was more that in the clean side of the cage. The role of such altering behaviors of M. hurrianae and their impact on social organization are discussed.     

Prenatal exposure to a low-frequency electromagnetic field demasculinizes adult scent marking behavior and increases accessory sex organ weights in rats

Pregnant Sprague-Dawley dams were exposed to a low-level, low-frequency pulsed electromagnetic (EM) field (15 Hz, 0.3 msec duration, peak intensity 8 gauss) for 15 min twice a day from day 15 through day 20 of gestation, a period in development that is critical for sexual differentiation of the male rat brain. No differences in litter size, number of stillborns, or body weight were observed in offspring from field-exposed dams. At 120 days of age, field-exposed male offspring exhibited significantly less scent marking behavior than controls. Accessory sex organ weights, including epididymis, seminal vesicles, and prostate, were significantly higher in field-exposed subjects at this age. However, circulating levels of testosterone, luteinizing hormone, and follicle-stimulating hormone, as well as epididymal sperm counts, were normal. These data indicate that brief, intermittent exposure to low-frequency EM fields during the critical prenatal period for neurobehavioral sex differentiation can demasculinize male scent marking behavior and increase accessory sex organ weights in adulthood.     

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.     

Communication impairments in mice lacking Shank1: reduced levels of ultrasonic vocalizations and scent marking behavior

Autism is a neurodevelopmental disorder with a strong genetic component. Core symptoms are abnormal reciprocal social interactions, qualitative impairments in communication, and repetitive and stereotyped patterns of behavior with restricted interests. Candidate genes for autism include the SHANK gene family, as mutations in SHANK2 and SHANK3 have been detected in several autistic individuals. SHANK genes code for a family of scaffolding proteins located in the postsynaptic density of excitatory synapses. To test the hypothesis that a mutation in SHANK1 contributes to the symptoms of autism, we evaluated Shank1(-/-) null mutant mice for behavioral phenotypes with relevance to autism, focusing on social communication. Ultrasonic vocalizations and the deposition of scent marks appear to be two major modes of mouse communication. Our findings revealed evidence for low levels of ultrasonic vocalizations and scent marks in Shank1(-/-) mice as compared to wildtype Shank1(+/+) littermate controls. Shank1(-/-) pups emitted fewer vocalizations than Shank1(+/+) pups when isolated from mother and littermates. In adulthood, genotype affected scent marking behavior in the presence of female urinary pheromones. Adult Shank1(-/-) males deposited fewer scent marks in proximity to female urine than Shank1(+/+) males. Call emission in response to female urinary pheromones also differed between genotypes. Shank1(+/+) mice changed their calling pattern dependent on previous female interactions, while Shank1(-/-) mice were unaffected, indicating a failure of Shank1(-/-) males to learn from a social experience. The reduced levels of ultrasonic vocalizations and scent marking behavior in Shank1(-/-) mice are consistent with a phenotype relevant to social communication deficits in autism.     

Home range size and population dynamic

A relationship between home range size and population density is developed. Dynamics of the adjustment of home range size to equilibrium are considered for two cases. When the equilibrial size is constant, actual home range size approaches the equilibrial value in an exponential fashion. When the equilibrial size is a variable determined jointly by many physical and biotic factors, home range size dynamics become complex. The dynamics are treated in the simplified case in which all factors affecting the equilibrial home range size are constant except population density. Equilibrial home range size as determined by population density is defined as the sum of the area available per animal and the per animal overlap of home ranges, with a quadratic function relating overlap to population density. During exponential population growth, home range size becomes constant as the population expands infinitely or contracts toward zero. Actually, home ranges might be disrupted at extreme high or low densities. With logistic growth, home range approaches a stable size between its maximal and minimal values if the carrying capacity lies in the range of population sizes for which the equilibrial home range size is variable.     

Effects of prepubertal ovariectomy on the development of scent glands, scent marking, and aggressive behaviors of female tamarin monkeys (Saguinus fuscicollis)

The effects of prepubertal ovariectomy on scent gland development, scent marking behavior, and on social interactions with strange adult conspecifics were studied in adult females cohabiting with intact males. Eight females were ovariectomized and eight underwent control surgery at 6 months of age. All were returned to their families after surgery and allowed to reach sexual maturity. At 18 months of age, each female was permanently paired with an adult, intact male. When the subjects were 21 months old, the social interactions of all pairs with strange adults were tested in a situation analogous to a territorial encounter. The scent marking activities of the subjects and their mates were studied during “territorial encounters,” in trial-free control situations, and in the presence of novel objects. Ovariectomy prior to puberty retarded the development of the scent gland but did not inhibit it completely. Social interactions with strange conspecifics were also affected. Ovariectomized females showed fewer threat displays than did control females, but there was no significant difference in the amount of injurious aggression both female groups directed at the strangers. Under all testing conditions, ovariectomized females tended to scent mark less frequently with the circumgenital-suprapubic gland than did controls. This difference was statistically significant only under some of the testing conditions. Intact females scent marked more frequently than their males but ovariectomized females did so only under trial-free testing conditions. The sternal scent gland was used very infrequently by all subjects and there was no difference in marking activity between males and females or between ovariectomized and control females.