Predicting Sex in White Rhinoceroses: A Statistical Model for Conservation Management.

Ensuring the effective management of every rhinoceros population is crucial for securing a future for the species, especially considering the escalating global threat of poaching and the challenges faced in captive breeding programs for this endangered species. Steroid hormones play pivotal roles in regulating diverse biological processes, making fecal hormonal determinations a valuable non-invasive tool for monitoring adrenal and gonadal endocrinologies and assessing reproductive status, particularly in endangered species. The purpose of this study was to develop a statistical model for predicting the sex of white rhinoceroses using hormonal determinations obtained from a single fecal sample. To achieve this, 562 fecal samples from 15 individuals of the Ceratotherium simum species were collected, and enzyme immunoassays were conducted to determine the concentrations of fecal cortisol, progesterone, estrone, and testosterone metabolites. The biological validation of the method provided an impressive accuracy rate of nearly 80% in predicting the sex of hypothetically unknown white rhinoceroses. Implementing this statistical model for sex identification in white rhinoceroses would yield significant benefits, including a better understanding of the structure and dynamics of wild populations. Additionally, it would enhance conservation management efforts aimed at protecting this endangered species. By utilizing this innovative approach, we can contribute to the preservation and long-term survival of white rhinoceros populations.

Preliminary Findings on How Different Management Systems and Social Interactions Influence Fecal Glucocorticoid Metabolites in White Rhinoceros (Ceratotherium simum).

White rhinoceroses (Ceratotherium simum) are the most social and gregarious species of all rhinoceroses known worldwide. One of the most critical effects of elevated glucocorticoid concentrations, especially in threatened species, is its relation to chronic stress, which could potentially lead to immunosuppression and reduced reproductive activity. Our aim is to determine how different social environments and management systems might be influencing the secretion of fecal glucocorticoids in white rhinoceroses. We have analyzed the concentration of fecal glucocorticoid metabolites in 658 fecal samples from 14 white rhinoceroses, seven free-ranging rhinos, and seven rhinos from two different managed captive populations. HPLC techniques were used to determine the main glucocorticoid metabolite found in this species, and a competitive EIA was used to establish fecal 5α-pregnan-3 3ß, 11ß, 21-triol-20-oneglucocorticoid metabolite (fGCM) levels. Our results reveal that management systems and social interactions had an influence on fGCM levels, suggesting that the more restrictive the management and social conditions are, the higher the glucocorticoid concentrations that are found. Additionally, sex was also found to influence fGCM levels, as in females, fGCM concentrations were higher than in males. We conclude that the analysis of glucocorticoids in relation to other factors is a powerful tool to assess adrenocortical response in white rhinoceros in order to broaden the knowledge of their reproductive biology and improve the management of the species.

Caretaker Score Reliability for Personality Assessment of Bottlenose Dolphin (Tursiops truncatus).

The evaluation of zoo animals' personalities can likely lead to a range of benefits, including improving breeding success, creating stable social groups, and designing and developing environmental enrichment programmes. The goal of this study was to use caretakers scores to evaluate personality in bottlenose dolphins and to assess the reliability of scores within each rater and among raters from each centre. To this end, 24 caretakers from 3 countries (Spain, France, and Argentina), including a total of 5 dolphinariums and 6 groups of dolphins, used a questionnaire based on the Five-Factor Model of Personality to score bottlenose dolphins on a number of personality traits in three different contexts. Each caretaker evaluated the animals under their care twice, ensuring that raters did not share thoughts nor impressions with other raters. Our findings showed a good degree of agreement between each rater's scores and a fair degree of agreement among scores of raters from the same centre. We also identified which raters and centres had significant mean score differences and detected that 4 out of 24 raters from two different centres showed such differences systematically. The evaluation of raters' reliability and the identification of particular inconsistent raters and centres is critical to make more appropriate and realistic management decisions that, in turn, directly impact animals' welfare.

Taenia crassiceps cysticercosis in a ring-tailed lemur (Lemur catta).

Subcutaneous and intraperitoneal cysticercosis due to Taenia crassiceps was diagnosed in a 5-yr-old male ring-tailed lemur (Lemur catta) in the Madrid Zoo-Aquarium (Madrid, Spain). Under laparoscopic examination, several septated fibrous cystic structures and numerous masses of small transparent vesicles (ca. 3 mm in diameter) were observed subcutaneously and inside the peritoneal cavity. Most of the structures were extirpated but, after 2 days of postsurgical intensive care, the animal died. The loss of body weight of the animal after surgical extirpation (566 g) represented 22% of the total weight (body weight before mass removal, 2582 g). The vesicles were identified under light microscopic examination as cysticerci and by molecular diagnosis as Cysticercus longicollis, the larval form of T. crassiceps. The present report represents the first detection of T. crassiceps in the prosimian genus Lemur.

Complicated urethral rupture and scrotal urethrostomy in a Bongo antelope (Tragelaphus eurycerus isaaci).

A 4-yr-old, 300-kg male Bongo antelope presented a fluctuant swelling on the ventral abdomen surrounding the penis, which was confirmed later as compatible with urethral rupture. Initial treatment included broad-spectrum antibiotic and radical surgical debridement. Total prepuce and partial penile amputation with orchidectomy was performed and normal micturition was restored. At a later stage, when the extent of the lesion was controlled, a permanent scrotal urethrostomy was performed. Complete healing by second intention was achieved 2 mo after the last surgery. Although the outcome was very good, considering the extent and severity of the tissue damage, prompt permanent urethrostomy when urethral rupture was first suspected would have prevented deterioration of the condition and prevented the need for extensive surgery.

Reintroduction of the Eurasian otter (Lutra lutra) in northeastern Spain: trapping, handling, and medical management.

In 1993 a reintroduction project for the Eurasian otter (Lutra lutra) was initiated in northeastern Spain (Girona, Catalonia) to restore extirpated populations. Between 1996 and 2000, 43 otters were captured from southwestern and northern Spain and from Portugal with modified foot-hold traps and transported to Barcelona Zoo. Lesions produced by capture were classified into four categories of increasing severity. Thirty four (79%) animals had category I, three (7%) had category II, five (12%) had category III, and only one (2%) had category IV injuries. During captivity five (11%) animals died, including one from a precapture problem. Radiotransmitter devices were implanted i.p. into 36 otters to monitor postrelease movement and survival. At least three radio-implanted otters have bred successfully in Girona province, Catalonia, after release in that area.