Zoo Biology最新文献

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.

Birds of prey are renowned for their excellent visual acuity, but they are often not given visual access consistent with their natural behavior when housed under managed care. Often, these birds are housed under managed care after sustaining injuries, which prohibits their return to the wild. In addition, many of these rescued raptors do not have the same history of acclimation to human presence as other zoo animals due to being wild-hatched. These factors lead to a potential welfare concern for raptors under managed care, which may not appropriately address their natural and individual histories. We assessed how the removal of a visual barrier (two large doors) may have affected behavior and space use of two bald eagles (Haliaeetus leucocephalus) housed at Zoo Miami. Before the visual barrier being removed, the eagles could not see people approaching their habitat from one out of two possible sides. We found that for one individual, stress behaviors such as gular fluttering significantly decreased after the removal of the visual barrier, and resting significantly increased. The birds also utilized their habitat more evenly after the visual barrier was removed and were seen at higher, more species-typical altitudes within the habitat. These findings suggest that increased environmental visual access for zoo-housed raptors may be a simple way to improve their overall welfare.

The shell of crocodilian eggs is highly fragile, especially during the early stages of development, making them susceptible to cracking during laying or collection, often resulting in embryo mortality. While numerous studies have explored various techniques for artificially incubating eggs to improve hatching success, particularly concerning issues with eggshells, there is limited information available on this topic for crocodilians. The objective of this research was to assess the hatching and survival success of cracked eggs using the windowing method and ex ovo incubation of Caiman latirostris (C. latirostris) embryos in a culture vessel. We used fertile eggs with cracked shells for the windowing eggs (WE) and ex ovo incubation (EE) treatments, and fertile noncracked eggs shell as control treatment. To ensure contamination-free incubation, all eggs were cleaned with alcohol. In the WE treatment, an eggshell section was removed, while in the EE treatment, embryos were removed from the eggshells. Each treatment was incubated in a culture vessel containing an aqueous antimicrobial solution at 31 ± 1°C. After 38 days of incubation in the culture vessel, the hatching success rates were as follows: 66.67% for WE, 0% for EE, and 100% for the control. Subsequently, the survival of hatchlings from the WE and control groups was 100%. The results suggest that incubation in artificial culture vessels enhances the viability and hatching success of C. latirostris cracked eggs. It works as an effective antimicrobial barrier maintaining sterile conditions and does not interfere with embryonic development. Moreover, the WE method offers unique possibilities for the monitoring of developmental studies and other manipulations of crocodilian embryos. However, the EE method is not advisable, as it does not reproduce the conditions inside the egg.

Assessing steroid hormones through feces provides invaluable insight on the stress and reproductive physiology of wildlife, and has been broadly applied to monitor the health and welfare of wild animals managed under human care. This study utilized fecal hormone monitoring to evaluate adrenal and gonadal activity in 18 captive lions (Panthera leo) across five Spanish zoological institutions, focusing on how biological and management factors affect these metrics. We analyzed fecal glucocorticoid metabolites (FGM) concentrations and, additionally in females, fecal progesterone (FPM), estradiol (FEM), and androgen (FAM) metabolites in relation to their reproductive status. Results indicated significant variability in FGM levels among individuals, with no consistent trends influenced by sex or zoo environment, including changes in the frequency of providing environmental enrichment at two zoos. Importantly, reproductive status significantly impacted adrenal and gonadal hormone levels; ovariectomized lionesses showed lower concentrations of FGM, FPM, and FEM compared to intact and deslorelin-implanted females, the latter of which exhibited higher and more variable FAM levels. These findings advance our understanding of hormone patterns in lions and suggest implications for their management in captivity.

Captive management of endangered species is a common conservation strategy. Monitoring the endocrine response related to reproduction and the increase of fecal cortisol metabolites is key to evaluating reproductive well-being and condition. We noninvasively assessed the endocrine status of captive European minks (Mustela lutreola) housed at Foundation for Research in Ethology and Biodiversity [FIEB] (a Spanish biodiversity conservation center) by measuring fecal glucocorticoid cortisol metabolite levels and testosterone, and progesterone metabolite levels. Males showed higher fecal cortisol and testosterone metabolite levels while no differences in fecal progesterone metabolite levels were found between sexes. Fecal levels of the three hormones were positively correlated. Individuals born in FIEB had lower fecal cortisol metabolites than those born in other centers and their values did not increase due to captivity duration. Hormone values obtained in FIEB could serve as a reference for this species management. However, further studies are required to ensure the well-being and reproductive success of captive and wild populations.

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.

Captive-release programs are an increasingly popular conservation strategy to combat wild extinctions. However, it is critical to determine if translocating animals from captive colonies ("source populations") leads to the establishment of new wild populations that are both stable and self-sustaining. To fill this knowledge gap, we provide a case study from the dusky gopher frog (Lithobates sevosus) reintroduction program to serve as an example for other critically endangered amphibians. In this study, we provide quantitative information on the reintroduction and survivorship of zoo-bred individuals that are released into the wild. This unique opportunity is the culmination of close to 20 years of collective efforts across multiple agencies. By taking advantage of the key monitoring window shortly after initial releases, we can formally declare the first successfully reintroduced, breeding population of dusky gopher frogs founded solely from a captive-bred colony.

Little is known about the reproductive biology of the endangered spinetail devil ray (Mobula mobular). Here, we describe the reproductive behavior, estimates of age, size at maturity, embryonic development in the uterine cavity, and the morphology of a neonate produced by a male and female ray kept in Osaka Aquarium KAIYUKAN for 7.5 years. The reproductive behaviors observed included initiation, endurance, evasion, pre-copulation positioning, copulation, and separation. The disc widths (DW) of male and female rays displaying reproductive behaviors were 203 and 204 cm, respectively. The male was estimated to be 7.7 years old after elongation of claspers, while the female was estimated to be 8.9 years old at first mating. A neonate was born 464 days after successful copulation, weighing 11.32 kg, with a DW of 104 cm. These observations are consistent with those of previous studies conducted on wild individuals. This is one of the few reports on the reproductive behavior of spinetail devil ray. Research conducted on this species in captivity is expected to help fill the knowledge gaps for this poorly studied species.

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.