The environment matters: season and female contact affect the behavior of captive Addax nasomaculatus male antelope.

The addax antelope (Addax nasomaculatus) is a species under serious threat of extinction, as it is more abundant in captivity than in the wild. However, little is known about its basic biology. The aims of this study were to determine how locomotor, feeding, aggressive, marking, and sexual behavior of male addax allocated in all-male groups vary with season and with female contact (i.e., biostimulation). The study was conducted in captive conditions, in two groups of adult males: one with no-physical contact with females, aside from visual and olfactory interactions (CF group, n = 4), and another group completely isolated from females (IF group, n = 4). The frequency of behaviors was recorded during the daytime, 4 days per season (total time of observation = 256 h). Lying, standing, walking, aggressive, marking, grazing, and ruminating behaviors as well as water and supplement consumptions varied with season (all p < 0.05). The lying, walking, marking, grazing, and ruminating behaviors were more frequently observed for CF than IF males (all p < 0.05). Also, all behaviors, except for marking, varied with the interaction between the group and seasons (all p < 0.05). Sexual behavior was extremely scarce, so it was not possible to analyze how it varied with seasons and the group. The present study suggests that management program and housing conditions, especially in ex situ breeding plans, should consider the influence of the season and the sociosexual context on the behavior of addax males.

Androgen and oestrogen receptors in the growing antlers velvet of adult and yearling pampas deer (Ozotoceros bezoarticus) males.

To determine the presence, quantity and distribution of androgen (AR) and oestrogen receptors (ER) in the antler velvet (AV), samples were collected from adult and yearling pampas deer males, as well as skin from the ventrolateral abdominal area (ASK). Samples were analysed with ligand-binding assays for AR and ER activity and processed for AR and ERß immunohistochemistry. There was more content of AR in adults than in yearling males (p = 0.02), as well as a category and type of tissue interaction (p = 0.03). There was more ER content in adults than in yearling males (p = 0.005) and in the AV than in the skin (p = 0.0001). The AR-positive score (PS) was greater in AV than in ASK in the surface stroma (p = 0.0007). In the intermediate epidermis, the AR PS was greater in adults than in yearling males (p = 0.04) and in the ASK than in the AV (p < 0.0001). There was a male category and type of tissue interaction for AR PS in the sebaceous glands (p = 0.014). The ERß PS in the surface stroma was greater in ASK than in AV (p = 0.004) and tended to be greater in yearling than in adult males (p = 0.093). The ERß PS in the intermediate epithelium and the sebaceous glands was greater in adults than in yearlings (p = 0.004 and p = 0.007, respectively). In conclusion, we reported for the first time the presence of AR and ER in the velvet skin of growing antlers in pampas deer males. Therefore, the velvet skin is sensitive to both androgens and oestrogens. Furthermore, the greater content of oestrogen receptors in the velvet of adult males suggests that adults are more sensitive to this hormone than yearlings, and thus, oestrogens have greater importance in velvet activity regulation in adult males.

To beat or not to beat: Behavioral plasticity during the antler growth period affects cortisol but not testosterone concentrations in red deer (Cervus elaphus) males.

Out of rut, male red deer (Cervus elaphus) associate themselves in bachelor groups where animals compete for rank position via agonistic interactions. In a previous study on red deer, males were recognized either as "Non-Fighters" (NF, low frequency of attacks) or "Fighters" (F, high frequency of attacks). This study, therefore, aims to verify the consistency of the inter-individual differences in fighting attitude across different social contexts and investigate whether they could be considered an individual characteristic. Behavioral consistency was presumed across three different sampling seasons, assuming that NF would have lower cortisol (C) and testosterone (T) concentrations than the F males. In 2015 the males were kept in one large group and labelled NF and F. In 2016, the herd was divided into two subgroups ("NF" and "F") based on the frequency of attacks. Finally, in 2017, the males were divided into two randomly composed subgroups. Data about agonistic behavior and concentration of C and T were collected during each season. In 2015 the individuals differed only for the fighting attitude. After the division, the frequency of the attacks always increased, being consistently lower in NF than in F. Unexpectedly, a slight increase in the concentration of C was detected in the NF in 2016, compared to the F who experienced no difference neither in 2015 nor 2017. No significant differences were found in T. We concluded that, even though the males had shown behavioral plasticity, their diversified interaction-prone attitude had been maintained despite the modifications of the social environment.

Adult and yearling pampas deer stags (Ozotoceros bezoarticus) display mild reproductive seasonal patterns with maximum values in autumn.

The pampas deer is an endangered species, from which reproductive biology little is known. We aimed to describe and compare the reproductive seasonal patterns of adult and yearling pampas deer stags throughout the year, including morphological traits, testosterone concentration, sperm morphology and cryoresistance pattern changes. Six adult (AS) and five yearling (YS) stags were captured with anesthetic darts once in winter, spring, summer and autumn to study morphological variables, serum testosterone and semen. Adult males were heavier, their neck girth tended to be greater and their testosterone concentration was higher than in YS. Animals were heavier in summer and autumn. Neck girth and testosterone concentration were greater in autumn. Scrotal circumference, testicular volume and gonado-somatic index varied with seasons, decreasing from winter to spring, increasing in summer and remaining in greater values in autumn. Sperm quality had maximum values from summer to winter. However, the cryoresistance ratio of motility score was greater in spring. In conclusion, in the captivity conditions, pampas deer stags seems to present a light seasonal reproductive pattern, with maximum testis size, testosterone secretion and fresh semen quality in autumn. Nevertheless, sperm cryoresistance ratio seemed to remain stable along the year. Although YS were still growing, they achieved similar semen quality than AS.

Aggressive interactions among female, semi-captive pampas deer (Ozotoceros bezoarticus) increase within the hierarchy and after short-term removal of the male.

Two trials were carried out to determine: (a) if there is a positive relation between the frequency of aggressive interactions among female pampas deer and their position within the hierarchy (HI), (b) if short-term removal of the male triggers an increase in the frequency of aggression, and (c) if the magnitude of this increase is related to the individual rank position of the female. Each of 19 breeding groups comprised one adult male and from four to six adult females. The HI was determined for each female and all aggressive interactions were recorded. These were recorded while the male was present (i.e., all of Trial 1 and the "with male" period in Trial 2) and after removal of the male (i.e., the "without male" period in Trial 2). The individual percentage change in the frequency of aggressive interactions after male removal was calculated. In Trial 1 the HI, the frequency of different types of aggressive interaction and the total of aggressive interactions were positively related (all: p < .001; General Linear Mixed Model [GLMM]). In Trial 2, the frequency of total aggressive interactions increased after male removal (F(1, 27) = 3.5; p < .001; GLMM). The individual percentage changes in aggressive interaction between periods were positively related to HI (F(6, 24) = 2.56; p = .05; GLMM). For female pampas deer maintained in breeding groups, we conclude that the frequency of aggressive interactions increases within the hierarchy. Aggression also increases after the short-term removal of the male, mainly among females of higher social status.

Reproductive biology of the pampas deer (Ozotoceros bezoarticus): a review.

The pampas deer (Ozotoceros bezoarticus) is a South American grazing deer which is in extreme danger of extinction. Very little is known about the biology of the pampas deer. Moreover, most information has not been published in peer-reviewed scientific journals, and is only available in local publications, theses, etc. Therefore, our aim was to update and summarize the available information regarding the reproductive biology of the pampas deer. Moreover, in most sections, we have also included new, unpublished information. Detailed descriptions are provided of the anatomy of both the female and the male reproductive tract, puberty onset, the oestrous cycle and gestational length. Birthing and the early postpartum period are described, as are maternal behaviour and early fawn development, seasonal distribution of births, seasonal changes in male reproduction and antler cycle, reproductive behaviour, semen collection, and cryopreservation. Finally, an overview is given and future directions of research are proposed.