Zoo Biology最新文献

Ozark hellbender (Cryptobranchus alleganiensis bishopi, Grobman 1943) populations in Missouri and Arkansas have been federally listed as endangered since 2011. As part of the comprehensive recovery plan for the subspecies, the Saint Louis Zoo WildCare Institute's Ron and Karen Goellner Center for Hellbender Conservation, in collaboration with the Missouri Department of Conservation, Arkansas Game and Fish Commission, and the U.S. Fish and Wildlife Service, established a conservation breeding and head-starting program to augment and create self-sustaining wild populations. We examined how the river of origin and egg origin (i.e., Zoo-bred or wild-bred) influenced various growth and mortality responses of Zoo-reared Ozark hellbenders. River of origin significantly predicted most larval and long-term Zoo-reared Ozark hellbender growth responses, with our results concurring with observed differences in wild populations and known genetic relationships between Ozark hellbender populations. Mortality of Zoo-reared Ozark hellbenders was often predicted by river of origin and egg origin with Zoo-bred hellbenders having significantly higher proportional mortality responses relative to wild-bred hellbenders. Further exploration of this egg origin relationship revealed differences between the Zoo breeding group generations with higher proportional mortality rates for hellbenders from the less mature second-generation breeding group relative to hellbenders from the first-generation breeding group and wild-bred hellbenders. Ultimately, our results provide baseline data on Zoo-bred and wild-bred Ozark hellbenders in the program, help identify differences in growth and mortality responses between Ozark hellbender populations, and contribute to existing evidence supporting distinct populations of Ozark hellbenders in Missouri to aid in targeted conservation strategies.

Accurate collection of biometric data is important for understanding the biology and conservation of marine organisms, including elasmobranch and teleost fish, both in nature and controlled environments where monitoring marine specimens' health is mandatory. Traditional methods involving specimen capture and handling are invasive, stressful, and disruptive. Some techniques like underwater visual census or laser photogrammetry have been used for noninvasive data collection, but they have limitations and biases. The application of stereo-video photogrammetry through the use of diver-operated stereo-video systems (stereo-DOV) is a noninvasive method that overcomes these challenges, providing highly accurate measurements. It has become popular for species monitoring, studying anthropogenic impacts, and assessing length distributions. However, this technique is still uncommon and barely reported in aquarium settings. This study describes an innovative pilot study targeting multiple species carried out in a Public Aquarium, using a low-cost house-made device. The results revealed that measuring more than 100 individuals in approximately 1 day's work is possible. Total and fork lengths were estimated using specific software for 31 teleost and 16 elasmobranch species and compared with real measurements for the available species. Despite technical limitations that must be reviewed for application in future studies that resulted in high root mean square (RMS) values (> 20 mm), differences between methodological approaches revealed a minimal discrepancy (1.37%-5% in large sharks and rays and 1.8%-5.5% in teleost fish). This technique has time and cost requirements, but might represent a major advance in husbandry and in the contribution to conservation that ex situ studies can provide.

There is relatively little work examining visitor outcomes of ambassador animal programs, such as whether these programs are educationally effective or unintentionally promote exotic pet ownership. We designed a two-way factorial experiment to test whether ambassador animals enhanced or detracted from the educational outcomes of a zoo exhibit. We surveyed 312 visitors at the Oakland Zoo at a static exhibit focused on the illegal wildlife trade. Participants were surveyed either before or after visiting the exhibit, with or without a trainer presenting either an ambassador ball python (Python regius) or yellow-naped Amazon parrot (Amazona auropalliata). The survey assessed attitudes toward conservation, knowledge of conservation behavior, and the suitability of various species, including the ambassador species, as pets. We used an ANOVA to examine 299 complete surveys for differences between experimental groups' mean responses. There were no significant differences in conservation attitudes. Subjects demonstrated more knowledge of conservation behavior after leaving the exhibit, regardless of whether or not an animal was present. While the exhibit reduced favorable attitudes toward parrots as pets, ambassador animal presence neither positively nor negatively impacted on this effect. Participants who viewed a python were more likely to indicate that they viewed a python as a good pet. However, the sample expressed overall negative attitudes toward exotic pet ownership. This study suggests that ambassadors neither enhanced learning nor unintentionally promoted exotic pets. Further research is needed to understand the role of interpretive messaging when using ambassadors in an educational context.

The secretarybird (Sagittarius serpentarius) is a threatened African raptor species, and as such requires conservation attention. While the species is managed under a European Association of Zoos and Aquaria (EAZA) Ex-situ Programme (EEP), no studies of mortality are currently available. A retrospective mortality project was therefore conducted to identify the most common causes of death in captive secretarybirds, with a view to informing management decisions. Data were collected by requesting the postmortem reports from zoos where secretarybirds had died and combining this with the existing data recorded in the Zoological Information Management System. Overall, 167 birds were recorded as having died within the EEP population, of which post-mortem information was available for 51 (30.54%) individuals. Trauma was the most common cause of death identified (22 birds, 13.17%), with infection appearing as the second most prevalent cause (15 birds, 8.98%). One incidental finding at postmortem was that many (9) birds showed evidence of liver damage, with reports of bacterial hepatitis, staphylococcal infection, lesions, and dark coloration. Further research into liver complications and diet composition for secretarybirds may therefore have value in reducing mortality. Similarly, investigating strategies to reduce trauma caused by other enclosure occupants or conspecifics may have value in lengthening lifespans for this endangered species.

"An elephant never forgets" is a popular phrase that refers not only to the elephant's extraordinary ability to remember migration routes but also to its pronounced social long-term memory (SLTM). Previous studies have shown intra- and interspecies SLTM performance, but the ability of elephants to have memories of individual humans has not yet been investigated. We tested this interspecific SLTM using auditory, olfactory, and visual stimuli, each from familiar and unfamiliar persons, in two African savanna elephant (Loxodonta africana) cows living in a zoo. The two-choice object tests revealed a higher interest in sensory stimuli from familiar keepers they had not seen for 13 years than in unfamiliar people. Statistically significant differences were found for olfactory stimuli. In addition, there was significantly more interest in visual stimuli from current keepers than in stimuli from unfamiliar people. Contrary to the results of a previous study with elephants, this was not observed for olfactory stimuli. Due to the small sample size and magnitude of the influencing factors, that is, outdoor experiment, only spatial separation of the animals, these results only represent indications of the possible interspecific SLTM. Nevertheless, we were able to provide the first empirical evidence that L. africana stores information about specific people over a long period of time. Further studies with larger sample sizes, cross-modal testing, and people disliked by the elephants could provide more insights.

Despite serum ferritin's potential as an iron status indicator, its concentrations vary significantly throughout a black rhinoceros's (Diceros bicornis) life, sometimes irrespective of iron load. We explored acute phase response-related biomarkers, serum amyloid A (SAA) and ceruloplasmin (Cp), to better understand the mechanisms influencing serum ferritin changes in managed black rhinoceroses. The objective was to evaluate the relationships between circulating levels of ferritin, SAA, and Cp in black and white rhinoceroses (Ceratotherium simum). We analyzed banked serum samples collected serially from 11 black (n = 222) and 7 white (n = 134), rhinoceroses (rhinos) and classified samples based on SAA values: clinically healthy (< 1 mg/L), subclinical (1-7 mg/L), or clinically abnormal (> 7 mg/L). In black rhinos, serum ferritin was not different between health status categories (p = 0.5292), nor was it correlated with SAA (p = 0.4164). However, Cp activity was significantly lower in clinically healthy sera (p < 0.0001) and had a moderate positive association with SAA (r = 0.477, p < 0.0001). Among the white rhino samples, only five had SAA values greater than 1 mg/L, limiting the assessment of ferritin and Cp activity in the health context. Minor, yet significant, relationships were observed between serum ferritin and Cp activity, negative in black rhinos (r = -0.206; p = 0.0022) and positive in white rhinos (r = 0.289, p = 0.0008). Cp activity may aid in diagnosing illness in black and white rhinos, based on values observed in sera collected near the time of death. However, acute inflammatory processes do not appear to be one of the primary drivers of the high ferritin concentrations detected in some black rhinos.

Clouded leopards are notoriously difficult to manage under human care due to their tendency toward high stress, intersex aggression, and limited reproductive success. This case study investigated the endocrinological interplay between adrenal and ovarian steroids and describes a positive correlation between concentrations of fecal estrogen and glucocorticoid metabolites in a female clouded leopard. The female was monitored through two sampling periods approximately 16 months apart, and each data set yielded similar results using a simple linear regression model. The finding of a significant positive correlation between the two steroids represents a novel finding in felids and a hitherto unidentified potential interplay between adrenal and ovarian steroid activity. It also adds to our collective understanding of the effects of estrus on female clouded leopards, impacting conservation efforts as we encourage reproduction in this vulnerable species.

Amphibians are facing an extinction crisis, with ex situ programs increasingly being used as a tool for their conservation. However, conservation efforts are often limited because we do not understand the ecological, behavioral, and life history traits of many amphibian species. Here, we report on the seasonal breeding patterns, egg-laying behavior, clutch size, and development of 11 frog species maintained at a conservation breeding facility in Andasibe, Madagascar. The frogs exhibited diverse breeding strategies aligned with life history theory. Counting the eggs in 1239 egg masses across these 11 species, we found endotrophic microhylids and terrestrial-breeding species had the smallest clutch size yet completed metamorphosis quickly, whereas species that laid eggs above or in water with exotrophic larvae had larger clutch sizes and took longer to develop. Most reproduction in captivity occurred during the warm, rainy season and followed seasonal patterns in temperature variation. Yet, Mantidactylus betsileanus bred throughout the year, and Heterixalus betsileo required additional environmental stimuli to trigger reproduction. Notably, we confirmed that Gephyromantis mitsinjo lays eggs on land with tadpoles developing terrestrially within jelly, a behavior previously theorized but which until now remained unobserved. Such observations show how captive breeding programs can be used to gain valuable data on the life history traits of species that are otherwise challenging to observe in nature. Our findings can be used to assess threats to closely related species, helping inform conservation efforts in a country harboring exceptional amphibian species richness and endemism.

Populations of Ozark hellbenders (Cryptobranchus alleganiensis bishopi, Grobman 1943) in Missouri and Arkansas are federally listed as endangered. The Saint Louis Zoo WildCare Institute's Ron and Karen Goellner Center for Hellbender Conservation, in collaboration with the Missouri Department of Conservation and US Fish and Wildlife Service, has developed a sustainable conservation breeding and head-starting program, a priority for species recovery. Using 9 years of program data, we examined various egg production, egg development, and mortality responses of Zoo-bred Ozark hellbenders. Our results identified river of origin and breeding location as important predictors of egg production responses including average breeding female total lengths as well as brooding male clutch size, total egg count, and the estimated number of female clutches, respectively. We found that breeding group generation was a significant predictor of Zoo-bred hellbender egg development responses with hellbenders from the first breeding group generation ovipositing later and producing eggs that hatch later and develop longer than hellbenders from the second-generation breeding group. These responses are consistent with females from the first breeding group generation being larger at the time of reproduction. Breeding group generation was also a significant predictor of proportional egg and total mortality, while the proportion of hatchling mortality was best predicted by breeding location, and the proportion of larval mortality was best predicted by river of origin. Ultimately, our results provide baseline metrics for the program and identify areas for further inquiry to maximize the success of future conservation breeding and head-starting efforts at the Zoo.

Humans were long thought to be the only mammal to experience menopause, the permanent cessation of reproduction followed by a long post-reproductive lifespan. More recently, evidence has been found for the existence of menopause in other long-lived mammals, including chimpanzees and gorillas. However, orangutans, which have the longest interbirth interval of any primate, have rarely been studied in this period of their lives. In this paper, we describe clinical, ultrasound, endocrine, and histological evidence consistent with a natural menopause in a captive, previously fertile, Sumatran orangutan (Pongo abelii), aged approximately 50. Consecutive serum samples showed low levels of estradiol and high levels of follicle-stimulating hormone. Transvaginal ultrasound revealed an atrophic uterus with an antero-posterior diameter of 2.36 cm, an endometrial thickness of 2 mm, and inactive ovaries. Following this female's death from a subdural hematoma, histological examination of the ovaries showed a dense stroma with corpora albicantia, in comparison to the numerous primordial follicles seen in the ovaries of a stillborn infant female orangutan. These multiple lines of evidence suggest that Sumatran orangutans can now be added to the list of mammals which undergo a true menopause, which may ensure that females' final offspring can be reared to independence.