Zoo Biology最新文献

This essay briefly presents the perspectives of multiple stakeholders regarding the care of captive marine mammals. Based on extant literature and professional experiences, the expectations, biases, and obstacles are described for the following perspectives: facilities, staff, guests, activists, scientists, third-party accreditations, governmental agencies, and marine mammals. All identified human stakeholders advocate for the animals, but the stakeholders have differing perspectives. The purpose of the article is to identify areas of impasse and areas of overlap to identify possible compromises to move toward a less contentious dichotomy. A summary of a recent case study involving the recently deceased killer whale, Tokitae, in managed care for 50+ years and the late-life transfer planned to return her to the Pacific Northwest provides an opportunity to illustrate the roles of each stakeholder involved. Also, several other cetacean examples are briefly summarized to illustrate the differing perspectives. Ultimately, compromises may be difficult given the disparate values and mindsets of the stakeholders. It seems that science should be allowed to weigh into this debate rather than allowing media attention, half-truths, and emotional appeals to govern policy and business models.

Previous observations of Rio Sao Francisco piranhas (Pygocentrus piraya) at Cleveland Metroparks Zoo revealed frequent aggressive interactions, which were associated with the injury and death of some individuals. Fishes are known to increase aggressive behavior when available space is limited. We compared the behavior of the piranhas longitudinally across three different space/density conditions: (1) in a group held in a small aquarium before the death of one individual, (2) in the same group after the death of one individual, (3) and in one individual of the group after it was later moved into a larger, multispecies aquarium. In the smaller aquarium, individuals maintained stable positions in the tank and remained inactive except to behave aggressively toward each other, retreat, or feed when food was offered. After the death of one individual, aggression decreased significantly but so did overall activity, including swimming behavior. After one individual was moved to a larger aquarium, it exhibited a striking increase in the amount of time spent swimming. Our data suggest that the well-being of P. piraya, and possibly other species of piranhas, might be better in large aquariums than in the small single-species exhibits often used in zoos and public aquariums. This study takes an important step in addressing the psychological and social well-being of bony fishes, an underrepresented area of research in zoos and aquariums.

Incubation of pink pigeon (Nesoenas mayeri) eggs under foster doves is an important element of the captive breeding program for this threatened species, and determining optimal species-specific incubation conditions could help to maximize hatchability. We analyzed 7 years of records (n = 104 eggs) from a captive collection to investigate whether the existing guideline for optimal total weight loss of 15% is appropriate for the pink pigeon. Successfully hatched eggs lost on average 14% of their initial mass during incubation, while a weight loss of 15.5% was associated with embryo mortality, and successful eggs lost slightly less weight per day, both as raw weight and as percentage of fresh weight. Eggs weighing at least 14 g at laying were significantly more likely to hatch than lighter eggs, indicating that low fresh weight may be the most useful predictor of embryo death in pink pigeons.

Management of African wild dogs (Lycaon pictus) in zoos involves several challenges, including the difficulty of providing appropriate stimulation and enrichment for naturally wide-ranging, energetic, cursorial hunters. Perhaps consequently, zoo packs can exhibit bouts of extreme intra-pack aggression rarely seen in the wild. As with other species, considerable efforts are required to balance the retention and exhibition of wild-type behaviors, against ensuring that the nutritional and welfare needs of individual group-living animals are met. While some behaviors, such as hunting and wide-ranging movements are impossible to mimic in zoos, the provision of food may be refined to allow natural feeding behavior to be displayed. We conducted a feeding experiment on a breeding pack of nine African wild dogs at Taronga Western Plains Zoo in Australia, presenting food in three treatments (individual pieces, butchered carcasses, and whole carcasses) to determine whether: (1) natural age-related patterns of feeding behavior were observed; (2) food type or presentation affected feeding behavior, duration, and interactions. Free-ranging African wild dogs exhibit an age-based feeding structure at kill sites that is rare in other species. We found that carcass and butchered carcass feeds more closely exhibited the age-based feeding observed in the wild. The pack spent twenty times as long consuming carcasses than food presented as individual pieces, with consumption times matching those in the wild. Carcass and butchered carcass feeds also increased the number and rate of interactions over food compared to individual pieces, with a high proportion of interactions resulting in sharing outcomes. This suggests that carcass feeds allow the exhibition of natural patterns of behavior without increasing the risk of negative social interactions. Our results highlight the importance and possibility of managing socially complex carnivores through husbandry that balances the display of natural behavior with positive animal welfare.

Human interference reduces wild felid populations. Somatic cell nuclear transfer and the use of induced pluripotent stem cells are potential conservation strategies. To improve the efficiency of these strategies, it is essential to establish adequate protocols for the synchronization of cells in the G₀/G₁ phase of the cell cycle. Cell cycle synchronization can arrest cell cycle progression by inhibiting factors involved in cell duplication. However, this step varies among wild felids and has not been successful in some species. In addition, the effect of this step on cell applications remains unclear. Therefore, this review highlights the primary differences among wild felids that can cause this variability, the most promising results, and the methods used. Finally, the importance of cell cycle synchronization in biotechnologies involving the nuclear reprogramming of somatic cells in wild felid conservation is highlighted.

Knowledge of the radiographic anatomy of rodent skulls is essential for accurately interpreting extra-oral radiographs, a non-invasive diagnostic tool commonly used in veterinary practice. Due to the complexity of the skull and the potential for distortion in two-dimensional views, a systematic evaluation of anatomical structures is necessary. This study identifies the most clinically relevant anatomical landmarks on standard extra-oral radiographic views of the skull and mandible in various rodent species, including a cane rat, two woodchucks, and seven common mole rats. Specimens were evaluated with bone and soft tissue intact, as well as dried skulls, to identify key anatomical features. The findings highlight distinct species-specific variations despite general similarities in skull structure. These landmarks were catalogued to aid veterinary professionals in interpreting rodent radiographs. Improved recognition of these structures enhances diagnostic accuracy, enabling better assessment of normal anatomy and potential pathological conditions in rodent patients.

Providing nutritionally balanced diets is a key aspect of successful husbandry and can help support sustainable ex situ populations. This study focuses on the diets of zoo-housed colobus monkeys (Colobus angolensis and C. guereza) and langurs (Trachypithecus cristatus and T. francoisi) across AZA institutions. We utilized survey responses from 34 institutions to (1) document the extent of dietary variation with regard to food categories and macronutrients offered, (2) assess interspecific variation in diets offered, and (3) identify important aspects of browse provisioning among institutions. A total of 95 different food items and 229 common-name browse types were offered across institutions. Leafy greens was the only food category offered at every institution. The proportion of root and non-root vegetables in the diet was highly variable. Nonstructural carbohydrates were the most variable macronutrient, and their concentrations were considerably higher than those food items consumed by free-ranging colobines. Conversely, neutral detergent fiber and acid detergent fiber contents were more consistent across institutions but were notably lower than those of free-ranging colobine food items. There were no significant interspecific differences in diets with regard to food categories or macronutrients offered. There was substantial variation in how frequently browse was offered, how it was regarded across zoos (either as diet, enrichment, or both), and whether or how it was quantified. This study provides context for future studies examining whether and how diet and macronutrient intake impact the behavior, health, and welfare of these populations.

The Sichuan golden snub-nosed monkey (Rhinopithecus roxellana) is a rare and endangered species endemic to China that occupies a particularly important position in the evolutionary history of Rhinopithecus species. Oral health is a crucial aspect of overall well-being in both humans and nonhuman primates. We review the current limited literature on the dental characteristics and dental pathologies related to the golden snub-nosed monkey, based on skeleton data and morphological evidence. The results indicated that this species possesses dental characteristics that are remarkably different from that of other primates such as larger-sized molars with blunt cusp crests, tiny incisor teeth, and strong mandibles with well-developed masticatory muscles. From limited research, dental diseases include caries, periodontal diseases, tooth loss, tooth wear, and other diseases, which can be found in most primates, including golden snub-nosed monkeys. In conclusion, these physiological features have gradually adapted to different environments to meet the requirements of their function. Understanding the tooth characteristics and dental health status of R. roxellana can provide valuable insights into their evolutionary history, dietary habits, and overall health, which is of great significance for the conservation of the entire population. An epidemiological survey and safe and effective inspection methods of the dental health of golden snub-nosed monkeys should be conducted to facilitate conservation behaviors that presented in the future. It is also recommended that zoos link diet and dental health to improve animal welfare.

Southern Ground-hornbills (SGHs) are listed as Vulnerable globally, and Endangered in South Africa, Namibia and Swaziland, due to poisoning, habitat loss and persecution. Successful conservation breeding and rearing of redundant second-hatched chick protocol has been established to supplement natural SGH populations in an attempt mitigate a declining population. However, captive rearing is costly and susceptible to loss of birds through conspecific aggression. Maximising the efficacy of reproductive output in captive settings and ensuring successful reintroductions of captive-reared birds to wild populations is of paramount importance if this species is to persist. Therefore, it is important to untangle the predictors of what drives mortalities in captive birds, particularly, through conspecific aggression. Using a database of captive SGH mortalities collected over 46 years we investigated whether variables such as season, age, relatedness, sex and husbandry predicted the occurrence of conspecific aggression in SGH. Aggression among adult, non-related birds particularly during SGH breeding season (austral spring) was the most predictable form of conspecific aggression. It was inferred that aggression is normally directed at non-related birds outside of already established social groups or at younger, related birds that are not dispersing from groups when reaching sexual maturity. Variables such as season, age, relatedness and husbandry were therefore all useful for predicting the potential and avoidable occurrence of an aggression event. Male birds were most often the aggressors. Making use of such variables to manage birds in a captive setting, move birds before sexual maturity and maintaining birds in known and accepted social structures could greatly improve management in SGH breeding facilities and optimise the efforts for re-establishing natural SGH populations.

A zoo-based, 11-year-old, uniparous southern black rhinoceros (Diceros bicornis minor) failed to conceive after weaning a calf. Behavioral observation and fecal progestagen monitoring confirmed irregular estrous cycles. Serial transrectal reproductive ultrasound examination revealed the cause to be recurrent anovulatory hemorrhagic follicles (AHFs). After four consecutive abnormal cycles dominated by AHFs, rational hormone therapy was implemented. Injectable prostaglandins, progesterone, estradiol, and a GnRH analog were given strategically to disrupt AHFs, boost normal estrus behavior, and promote ovulation. Oxytocin was added to the treatment regimen when transient accumulations of intraluminal uterine fluid consistent with endometritis were observed ultrasonographically. Oral diazepam was given judiciously for anxiolysis after the animal developed an aversion to injection. Treatment, which proceeded over eight cycles, was eventually associated with the restoration of normal behavioral estrus and ovulation. The rhinoceros conceived after natural mating and induced ovulation, delivering a healthy calf 490 days later, the longest reported gestation for the species.