The effect of pregnant and oestrous females on male testosterone and behaviour in the tammar wallaby

Tammar wallaby females (Macropus eugenii) are seasonally breeding marsupials with a post-partum oestrus after a highly synchronised birth period when testosterone concentrations rise in males. Chemical communication appears to be important for mating, as males show checking behaviour, sniffing the urogenital opening (UGO) and the pouch of females. This study investigates whether the presence of pregnant and oestrous females directly influences testosterone in males and if oestrous odours or secretion from the pouch or UGO are attractive. Concentrations of plasma testosterone were measured in males housed with pregnant and oestrous females during two consecutive cycles in the breeding season, and an artificially induced cycle in the non-breeding season. Males were also tested for their interest in swabs taken from the urogenital opening (UGO) or pouch of oestrous females. Testosterone increased sharply in males in the presence of pregnant and oestrous females during all cycles in both seasons, but there was no change when males were exposed to non-cycling females in lactational or seasonal diapause. Males had no preference for either oestrous or non-oestrous samples taken from the pouch or from the UGO from oestrous females. This study confirms that the increase in plasma testosterone in tammar males can be induced through the presence of pregnant and oestrous females, regardless of season and that the increase began when the females were in late-pregnancy. This confirms that the male's reproductive state is dependent on a signal from females and is not blocked through seasonal effects.     

Anandamide Levels Fluctuate in the Bovine Oviduct during the Oestrous Cycle

Mammalian oviduct acts as a reservoir for spermatozoa and provides an environment in which they may compete for the opportunity to fertilize the oocyte. Whilst in the oviduct spermatozoa undergo capacitation essential for fertilization. Sperm-oviduct interaction is essential for sperm capacitation and is a tightly regulated process influenced by the local microenvironment. Previously we reported that the endocannabinoid anandamide (AEA) regulates sperm release from epithelial oviductal cells by promoting sperm capacitation. The aims of this work were to measure the AEA content and to characterize the main AEA metabolic pathway in the bovine oviduct and determine how these change through the oestrous cycle. In this study, the levels of AEA and two other N-acylethanolamines, N-oleoylethanolamine and N-palmitoylethanolamine, were measured in bovine oviduct collected during different stages of oestrous cycle by ultra high performance liquid chromatography tandem mass spectrometry. Results indicated that intracellular oviductal epithelial levels of all three N-acylethanolamines fluctuate during oestrous cycle. Anandamide from oviductal fluid also varied during oestrous cycle, with the highest values detected during the periovulatory period. Endocannabinoid levels from ipsilateral oviduct to ovulation were higher than those detected in the contralateral one, suggesting that levels of oviductal AEA may be regulated by ovarian hormones. The expression and localization of N-acylethanolamines metabolizing enzymes in bovine oviduct were also determined by RT-PCR, Western blot, and immunohistochemistry but no change was found during the oestrous cycle. Furthermore, nanomolar levels of AEA were detected in follicular fluids, suggesting that during ovulation the mature follicle may contribute to oviductal AEA levels to create an endocannabinoid gradient conducive to the regulation of sperm function for successful fertilization.     

Contamination of livestock due to the operation of a small waste incinerator: a case incident in Skutulsfjörður,Iceland, in 2010

Background

Declining fertility is a major concern for dairy farmers today. One explanation is shorter and weaker expression of oestrus in dairy cows making it difficult to determine optimal time for artificial insemination (AI). Chemical communication is of interest in the search for tools to detect oestrus or to synchronise or enhance oestrous periods. Pheromones, used in chemical communication within species, can influence reproduction in different ways. The aim here was to investigate whether oestrous cycle length, and duration and intensity of oestrous expression in dairy heifers could be manipulated through exposure to pheromones in oestrual substances from other females.

Methods

Beginning on day 16 of two consecutive control oestrous cycles, ten heifers of the Swedish Red Breed (SRB) were exposed to water. During the two following cycles the heifers were exposed to urine and vaginal mucus, obtained from cows in oestrus. Cyclicity parameters were monitored through hormone measurements, oestrus detection and ultrasonographic examination.

Results

We found no difference in cycle length or in duration of standing oestrus between control and treatment. We did, however, find a tendency of interaction between type of exposure (control or treatment) and cycle number within type of exposure for cycle length (p = 0.068), with the length differing less between the treatment cycles. We also found a tendency of effect of type of exposure on maximal concentration (p = 0.073) and sum of concentrations (p = 0.063) of LH during the LH surge, with values being higher for the control cycles. There were also significant differences in when the different signs of oestrus occurred and in the intensity of oestrous expression. The score for oedema and hyperaemia of external genitalia was significantly higher (p = 0.004) for the control cycles and there was also a significant interaction between type of exposure and time period for restlessness (p = 0.011), with maximum score occurring earlier for treatment cycles.

Conclusions

No evidence of altered oestrous cycle length or duration of oestrus after exposure of females to oestrous substances from other females was found. Expression of oestrus, and maybe also LH secretion, however, seemed influenced by the exposure, with the effect of treatment being suppressive rather than enhancing.     

Mate searching behaviour of elephant bulls in a semi-arid environment

In the wet season, African elephant (Loxodonta africana Blumenbach) bulls switched from a strategy associated with feeding to one where the travelled long distances in search of oestrous females. Bulls which associated with cows behaved quite differently from other bulls. In sparse elephant populations a bull may have a greater chance of associating with an oestrous female if he lives permanently with a group of cows (the traditional concept of the herd bull) instead of searching for receptive cows during the mating season.     

Plasma Ghrelin Concentrations Were Altered with Oestrous Cycle Stage and Increasing Age in Reproductively Competent Wistar Females

Changes in appetite occur during the ovarian cycle in female mammals. Research on appetite-regulatory gastrointestinal peptides in females is limited, because reproductive changes in steroid hormones present additional experimental factors to control for. This study aimed to explore possible changes in the orexigenic (appetite-stimulating) gastrointestinal peptide hormone ghrelin during the rodent oestrous cycle. Fed and fasted plasma and stomach tissue samples were taken from female Wistar rats (32–44 weeks of age) at each stage of the oestrous cycle for total ghrelin quantification using radioimmunoassay. Sampling occurred during the dark phase when most eating takes place in rats. Statistical analysis was by paired-samples t-test, one-way ANOVA on normally distributed data, with Tukey post-hoc tests, or Kruskal-Wallis if not. GLM univariate analysis was used to assess main effects and interactions in ghrelin concentrations in the fed or fasted state and during different stages of the ovarian cycle, with age as a covariate. No consistent fed to fasted ghrelin increases were measured in matched plasma samples from the same animals, contrary to expectations. Total ghrelin concentrations did not significantly change between cycle stages with ANOVA, in either fed or fasted plasma or in stomach tissue. This was despite significantly decreased fasted stomach contents at oestrus (P = 0.028), suggesting decreased food intake. There was however a significant interaction in ghrelin plasma concentrations between fed and fasted proestrus rats and a direct effect of age with rats over 37 weeks old having lower circulating concentrations of ghrelin in both fed and fasted states. The biological implications of altered ghrelin plasma concentrations from 37 weeks of age are as yet unknown, but warrant further investigation. Exploring peripheral ghrelin regulatory factor changes with increasing age in reproductively competent females may bring to light potential effects on offspring development and nutritional metabolic programming.     

Mate Choice in Female Red-necked Pademelons,Thylogale thetis (Marsupialia: Macropodoidea)

Changes in the behaviour of captive female red-necked pademelons, Thylogale thetis, before, during and after oestrus were observed relative to the location of potential male mates. A penned female was presented with four adjacent, individually caged males representing the size classes large, medium, small and subadult. The female's behaviour was videotaped for 8–9 d spanning oestrous (3 d), post-oestrous (3 d) and normal (3 d) sessions of time. Changes in the activity, orientation and location of six penned females, relative to the caged males, were transcribed from videotape. A model of female pademelon behaviour pattern was developed. Results suggest that the females spent a significantly greater amount of time directly in front of the largest available male, relative to the other three smaller males during the oestrous period only, and that a significant proportion of this time was spent involved in active behaviours (grooming and locomotion, compared with inactive behaviours of sitting and scan/sniffing). Although there was a significant preference for females to orientate their bodies away from the location of the males, they faced the males significantly more during oestrus than any other session. Furthermore, the females faced the large male significantly more frequently than any other male. This study provides evidence for mate choice by female red-necked pademelons.     

The oestrous cycle of the brown lemur, Lemur fulvus.

Examination of vaginal smears and observations of the colour and tumescence of the genitalia and discharge of mucus of 9 brown lemurs indicated that the oestrous cycle lasted for 30 days and that cycles occurred between September and July. The timing of cycles of females housed in visual isolation differed from that of females able to see other lemurs, indicating that the oestrous cycle in this species can be influenced by different housing conditions.     

Betaine Elevates Ovarian Antioxidant Enzyme Activities and Demonstrates Methyl Donor Effect in Non-Pregnant Rats

Chronic alcoholism leads to infertility in male and female rats, and antioxidant enzymes form the first line against oxidative stress in organisms. In recent years, betaine has shown beneficial effects on various tissues, and this study has attempted to clarify antioxidant and methyl donor properties of betaine in the rat ovary. For this purpose, the sexually matured Sprague-Dawley female rats were divided into Control, Ethanol (EtOH), Betaine, and Betaine?+?EtOH groups. Administration of betaine in Betaine?+?EtOH group significantly increased CAT activity when compared to the other groups (P?<?0.05). GPx activity increased significantly in Betaine and Betaine?+?EtOH groups as compared to controls (P?<?0.05). Interestingly, GPx and CAT activities insignificantly increased (in order compensatory) in EtOH group to suppress oxidative stress. In contrast, SOD activity decreased insignificantly in EtOH group compared to Betaine?+?EtOH and control groups (P?>?0.05). TBARS concentration (as a lipid peroxidation marker) significantly increased in ethanol-treated rats as compared to controls, while total homocysteine concentration significantly decreased in betaine-treated rats in comparison with EtOH group. Regarding to oestrous cycles, ethanol-treated animals had irregular estral cycle and persistent oestrous phase compared to controls and betaine-treated rats. In conclusion, these results demonstrate for the first time the antioxidant and methyl donor properties of betaine in the rat ovary. Thus, betaine might be used as a potential therapy in hyperhomocysteinemia and partial infertility mediated by oxidative stress in females.     

Dynamics of male residence and female oestrus during a breeding season of blue monkeys in the Kakamega Forest, Kenya

Blue monkeys (Cercopithecus mitis stuhlmanni) are seasonal breeders with a dynamic mating system in which typical one‐male social units are regularly disrupted and replaced by multi‐male ones. The number of males in the group is correlated with the number of oestrous females. We used observations of male presence and female oestrus on individual days during a 6‐month period to assess whether the presence of multiple males in a group stimulates female oestrus or whether oestrous females attract multiple males to the group. We confirmed prior observations with our finding that the number of males in a group was significantly correlated (r_s = 0.435, P < 0.0001) with the number of oestrous females across 126 observation days. A transition matrix did not show an obvious relationship between day‐to‐day changes in the numbers of oestrous females and males. However, cross‐correlation analysis provided stronger support for the idea that the number of oestrous females attracts males to a group than for the idea that the influx of strange males stimulates oestrus in female blue monkeys. Autocorrelation analysis showed that while female oestrus appeared to show a high degree of synchrony, as expected in a seasonal breeder, there was no evidence that the number of males accompanying a group of females influenced the likelihood of other males joining or leaving the group. Overall, our results confirm that female oestrous behaviour stimulates changes in male residence patterns. However, other observations suggest that changes in male residence may also stimulate female oestrus in some circumstances.     

Social correlates of variation in urinary cortisol in wild male bonobos (Pan paniscus)

Cortisol excretion in males of group living species is often associated with social rank and competition for oestrous females. Rank-related patterns of cortisol levels can be used to study mechanisms of rank maintenance and costs associated with mate competition. Bonobos (Pan paniscus) are interesting because males form a linear dominance hierarchy but are not dominant over females and therefore aggressive male-male competition over access to females alone is not considered to be a successful reproductive strategy. In this study on social correlates of urinary cortisol in wild male bonobos, we investigated the relationship between cortisol levels and several aspects of mate competition, including male rank, aggression rates, and association time with oestrous females. We found that cortisol levels correlated positively with dominance rank when oestrous females were present, but not when they were absent. This result is consistent with the idea that aggressive behaviour plays a minor role in maintenance of high rank. While aggression received from males and females explained within-individual variation in cortisol levels, it was the time spent in association with oestrous females that best explained between-individual variation in male cortisol levels. The observed increase in male cortisol may be associated with spatial proximity to oestrous females and could result from anticipated aggression from other group members, reduced feeding time in the males, or a combination of both.     

Relationships between intravaginal electrical resistance,cervicovaginal mucus characteristics and blood progesterone and LH

Measurements of intravaginal electrical resistance (Rv) were made on seven Hereford × Friesian heifers throughout a synchronised and a normal oestrous cycle. Measurements were taken at depths of 10, 20 and 25 cm in the vagina, using a hand-held probe with two gold ring electrodes connected to a resistance meter. Mucus samples were obtained at different stages of the oestrous cycle and analysed for Cl, Na, Ca and K. Ferning pattern values were also estimated. Progesterone and LH were determined in blood samples taken at different stages of the cycle.Rv and ferning values were more closely related to either Cl or Na than to either Ca or K. Measurements of Rv taken at a depth of 20 or 25 cm inside the vagina were more closely associated with changes in mucus components than those taken at a depth of 10 cm.Rv fluctuated throughout the dioestrous period but a pronounced fall of about 25% was seen at oestrus. The lowest value occurred early in the second half of the oestrous period and coincided with the time of the LH peak. Smaller variations during dioestrus and a larger drop in Rv at oestrus were obtained when measurements were taken at the anterior rather than posterior part of the vagina. A curvilinear relationship was obtained between serum progesterone and Rv measurements (r = 0.62).     

The effect of cloprostenol in non-pregnant and pregnant Norwegian semi-domestic reindeer (Rangifer tarandus tarandus L)

Two non-pregnant and five pregnant 1.5-year-old semi-domestic reindeer were used to study the effect of cloprostenol given during the luteal phase of the oestrous cycle, or at two stages of pregnancy (early December, n = 3, and mid-January, n = 2). Blood samples were collected at 3-hourly intervals from immediately prior to treatment until 6–8 days after treatment, after which blood samples were collected every second day. Prior to each blood collection, the animals were observed for signs of oestrus. Plasma progesterone, oestradiol-17β, luteinizing hormone (LH) and 15-ketodihydro-PGF_2α were analyzed to characterize variations in ovarian function.Treatment with cloprostenol resulted in an immediate and rapid decrease in plasma progesterone concentrations in all treated animals. The fall in plasma progesterone was associated with increase in 15-ketodihydro-PGF_2α. Oestrus, indicated by standing behaviour, was observed on three out of four occasions in the two non-pregnant animals. The average duration of standing behaviour (oestrus) was 27 h (range: 24–30 h).Of the pregnant females that were treated with cloprostenol in the beginning of December (n = 3), two aborted between 72 and 96 h after treatment. One of these developed pyometra after abortion. In one female the foetus died 2 days after treatment, but was retained within the uterus until slaughter 2.5 months later. One of the two females that were treated in mid-January aborted between 62–65 h after injection. The other female retained a live foetus until slaughter in February. There were few endocrinological differences between animals that aborted and those that did not, though aborting animals had lower progesterone concentrations for a longer period of time after treatment.It was concluded that cloprostenol can be used during the luteal phase of the oestrous cycle to induce luteolysis and oestrus. When given during pregnancy, cloprostenol can induce abortion, though undesired side effects make it inappropriate for practical use.     

Social influences on oestrous cycle length and plasma progesterone concentrations in the female lesser mouse lemur (Microcebus murinus)

Plasma progesterone concentrations were recorded during one breeding season in 19 lesser mouse lemur females living in different social conditions. The oestrous cycle length and the progesterone profile mainly depended on the social environment of the female. For totally isolated females, the oestrous cycle lasted 38 +/- 5.7 days and included a 25-30-days spontaneous luteal phase with a progesterone peak about 100 ng/ml between the 20th and 25th days after oestrus, and a prolonged preovulatory period of 10-15 days which could be considered equivalent to the follicular phase of a menstrual cycle. When females were able to communicate through olfactory, visual and auditory signals, the oestrous cycle was significantly lengthened (53.7 +/- 5.9 days). When females had tactile contacts, the oestrous cycle was further lengthened (62.7 +/- 0.8 days). This lengthening of the oestrous cycle was related to an extension of the luteal phase associated with a decrease in progesterone concentrations during this period. In females maintained with one male (paired) or with males and females (heterosexually grouped), large individual variations were shown in cycle lengths or in progesterone concentrations. In these females, cycle lengths and progesterone concentrations were inversely correlated to plasma cortisol concentrations.     

Spatial working memory in rats: no differences between the sexes

In a number of mammalian species, males appear to have superior spatial abilities to females. The favoured explanations for this cognitive difference are hormonal, with higher testosterone levels in males than females leading to better spatial performance, and evolutionary, where sexual selection has favoured males with increased spatial abilities for either better navigational skills in hunting or to enable an increased territory size. However, an alternative explanation for this sex difference focuses on the role of varying levels of oestrogen in females in spatial cognition (the 'fertility and parental care' hypothesis). One possibility is that varying oestrogen levels result in variation in spatial learning and memory so that, when tested across the oestrous cycle, females perform as well as males on days of low oestrogen but more poorly on days of high oestrogen. If day in the oestrous cycle is not taken into account then, across an experiment, any sex differences found would always produce male superiority. We used a spatial working memory task in a Morris water maze to test the spatial learning and memory abilities of male and female rats. The rats were tested across a number of consecutive days during which the females went through four oestrous cycles. We found no overall sex differences in latencies to reach a submerged platform in a Morris water maze but, on the day of oestrus (low oestrogen), females took an extra swim to learn the platform's location (a 100% increase over the other days in the cycle). Female swim speed also varied across the oestrous cycle but females were no less active on the day of oestrus. These results oppose the predictions of the fertility and parental care hypothesis.     

The corpora lutea proangiogenic state of VEGF system components is turned to antiangiogenic at the later phase of the oestrous cycle in cows

Blood vessel expansion and reduction in the corpus luteum (CL) is regulated by the vascular endothelial growth factor (VEGF) system and linked to the maintenance of the CL. The VEGF system has both angiogenic and antiangiogenic ligands and receptors. Our objective was to evaluate the relationship between the mRNA expression of angiogenic and antiangiogenic members of the VEGF system in the CL, throughout the luteal phase of the oestrous cycle in cows. The CL of 18 cows were collected by transvaginal surgery on days 4, 6, 9, 12, 15 and 18 of the oestrous cycle and the mRNA expression of VEGF system components was evaluated by quantitative real-time PCR. The mRNA expression of VEGF ligands and receptors increased (P<0.05) from the early- and mid-luteal phase (days 4 to 12) reaching its maximum expression on day 15 of the cycle. We found no expression of VEGF164b throughout the cycle. Expression of sVEGFR1 did not change during the oestrous cycle and exceeded that of the VEGFR1 by 100 times. Nonetheless, as VEGFR1 increased, the relationship between the soluble and membrane receptor decreased (P<0.01). In contrast, the expression of VEGFR2 was higher than that of its soluble isoform for all days studied, however, the ratio between the membrane-bound and its soluble counterpart decreased continuously throughout the cycle (P<0.01). Our results show that the expression levels for VEGF ligands, receptors and their antagonistic counterparts are adjusted during CL development and regression, to upregulate angiogenesis early in the oestrous cycle and restrict it at the time of luteolysis.     

Oestrus in the Julia Creek dunnart (Sminthopsis douglasi) is associated with wheel running behaviour but not necessarily changes in body weight,food consumption or pouch morphology

The Julia Creek dunnart (Sminthopsis douglasi) is an endangered carnivorous marsupial belonging to the family Dasyuridae. This study investigated the oestrous cycle of this species in terms of its reproductive physiology and behaviour to explore more efficient methods of oestrus detection. Ten sexually mature captive female dunnarts were monitored daily at David Fleay Wildlife Park, Burleigh Heads, Australia, from mid September to late December 2006 for changes in urogenital cytology within the urine (0, 1+, 2+ and 3+), running wheel activity, body weight, uneaten food, faecal steroid metabolites (progesterone and oestradiol) and pouch development. Periods of increased running wheel activity were associated (p = 0.004) with an increase in the proportion of cornified urogenital epithelial cells found in the urine; periods of decreasing weight (p < 0.001) and uneaten food (p < 0.001) were also associated with changes in urogenital cytology but not to the point where they would be useful for oestrus detection. Between 60.3% and 92.0% of peak distances (confidence interval 95%) occurred when the epithelial cell index was 2+ or 3+. Only 15.5–37.5% of peak weights (CI: 95%) and 28.1–49.9% of incidences of uneaten food (CI: 95%) occurred when the epithelial cell index was 2+ or 3+. There was no significant difference in the mean length of the oestrous cycle when measured by urogenital cytology (mean ± SD: 25.0 ± 5.7 days; n = 20) or peak distance travelled (mean ± SD: 25.4 ± 5.7 days; n = 20). Changes in the concentration of oestradiol metabolites in Julia Creek Dunnart faeces were not useful in characterising the oestrous cycle. Wheel running activity declined markedly with increased faecal progestagen concentration. The majority of the pouch variables examined showed maximum development during the inter-oestrus period but as there was considerable variation between animals, the pouch was not considered a useful index of oestrus.     

Group mating among Norway rats I. Sex differences in the pattern and neuroendocrine consequences of copulation

The copulatory pattern of groups of rats (Rattus norvegicus) was studied in the laboratory in a seminatural environment. In a given mating session, every oestrous female copulated with each male; likewise, every male copulated with each oestrous female. While individual males and females experienced similar amounts of copulation, there were dramatic sex differences in sequence and temporal pattern. Males mated in a multiple intromission pattern and had more ejaculatory series when several females were in oestrus. In contrast, females received intromissions and ejaculations in a random order, not in the sequence of a male ejaculatory series. Males copulated at shorter intervals than females did, a temporal sex difference that was determined by the pattern of female solicitations and male approaches. These sex differences are used to discuss the different units of analysis that are appropriate for male and female sexual behaviour in this species. Furthermore, the sex differences in the temporal pattern of copulation which emerged during group mating parallel the known sex differences in the temporal parameters of the neuroendocrine reflexes which mediate successful reproduction in the domestic strain.     

Secretion of gonadotrophins change during the luteal phase of the bovine oestrous cycle in the absence of corresponding changes in progesterone or 17β-oestradiol

The hypothesis in the present study was that changes in circulating luteinizing hormone (LH) and follicle stimulating hormone (FSH) would occur during the luteal phase of the oestrous cycle (Days 4–19; Day 0, day of behaviourial oestrus) that were not related to corresponding changes in concentrations of progesterone and 17β-oestradiol. The stage of the oestrous cycle of cows (n = 18) was synchronised to obtain cows that were on alternate days of the cycle. Blood samples were collected every other day at 15 min intervals for 12 h from all cows: Days 4, 6, 8, 10, 12, 14, 16, 18 (n = 9) and Days 5, 7, 9, 11, 13, 15, 17, 19 (n = 9). Concentrations of LH, FSH, 17β-oestradiol and progesterone were determined in these samples. Data were compared across days to determine when significant changes occurred in concentrations or patterns of secretion of the gonadotrophins and ovarian steroid hormones during the oestrous cycle. There were significant changes in mean concentrations of FSH in circulation between Days 6 and 12. The most striking changes in secretion of gonadotrophins that could not be explained by changes in gonadal steroids were the fluctuations in amplitude of LH pulses between Days 7 and 12. Amplitude of LH pulses increased between Days 7 and 11 and subsequently decreased between Days 11 and 12 of the oestrous cycle. Some changes in gonadotrophin secretion that occurred in the present study can be explained by fluctuations in concentrations of progesterone and 17β-oestradiol in circulation. Other changes cannot be explained by fluctuations in circulating concentrations of these steroids. We accept our hypothesis because the concomitant changes in mean concentration of FSH between Days 6 and 11 and amplitude of LH pulses between Days 7 and 12 of the bovine oestrous cycle cannot be explained by changes in circulating concentrations of progesterone and 17β-oestradiol.     

The reproductive and heterosexual behaviours of adult patas monkeys in captivity

The reproductive, agonistic, and social interactions between the adult male and adult females of a patas monkey (Erythrocebus patas) harem were investigated. The occurrence of oestrus appeared to be influenced by both social and hormonal factors. Oestrus was not limited to the peri-ovulatory period, but also occurred at other times within the menstrual cycle and after conception. Mating behaviour was correlated with seasonal decreases in daylength and temperature. The male showed no clear preference for either non-pregnant or pregnant sexual partners. Female dominance rank appeared to have little influence on intrasexual competition for copulations. Of the non-reproductive behaviours studied, only two (female-to-male grooming and heterosexual sitting-close) showed significant fluctuations in frequency with changing female reproductive state. For both behaviours, non-pregnant oestrous females showed the highest frequencies.     

Marking behaviour of the bahaman hutia (Geocapromys ingrahami)

The marking behaviour of a rare hystricomorph rodent, the Bahaman hutia (Geocapromys ingrahami), was studied in captivity. Hutias were more likely to mark urine-scented sticks than to mark unscented controls. The odour of conspecific urine readily induced marking and the sight and/or odour of an animal marking often immediately led to marking by other animals. Marking was exhibited by both males and females regardless of whether females were in oestrus. Olfactory investigation and marking by males was more intense, however, in the presence of oestrous females or their scent. Marking appears to be primarily a non-agonistic, social behaviour which may be important in the social organization of this gregarious, nocturnal species.