Zoo Biology最新文献

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.

In Thailand, tigers are more numerous in captivity than they are in the wild, with 51 facilities housing approximately 1962 tigers. As charismatic fauna, tigers are popular with tourists, and the majority of facilities offer a variety of entertainment activities with controversial reports towards the animals' welfare. The aim of this research was to investigate tiger welfare in Thai zoos to identify specific welfare issues. We assessed 34 tourism facilities holding tigers in Thailand in 2019 using a 25-point welfare assessment that utilizes the Five Domain model (incorporating all five domains: nutrition, physical environment, health, behavioural interactions and mental state). The mental domain score was derived from the scores of the other four domains. Additional data were collected from each facility, including the number of tigers, any colour variants, types of human interaction and admission cost. Welfare scores for each domain were calculated by totalling the scores per domain and dividing by the number of points allocated to that domain. A multiple regression was used to identify any significant predictors of mental domain score. The results revealed that the provision of a suitable physical environment scored the lowest, while nutrition scored the highest though this was still a low score overall. The multiple regression showed that 45.4% of the variance for the mental domain score was significantly affected by the number of colour variants housed and the types of human interaction available with facilities, with more of both these factors contributing to a more negative score. Our results demonstrate the need for urgent, comprehensive infrastructural, species-appropriate environment and design and animal management improvements to increase animal welfare. Informed institutional change toward the breeding and use of tigers for public interactions is also required. This is the first assessment completed of captive tiger welfare of tiger facilities in Thailand and shows that the welfare concerns encountered are within a high proportion (67%) of Thailand's facilities. This supports the need for the creation and enforcement of effective and clear captive wildlife operational standards to provide a sustained solution for captive tiger welfare and can provide a considered approach to ex-situ tiger management that, in conjunction with in-situ efforts, can improve much needed conservation efforts of this species.

Hand-reared animals are invaluable and irreplaceable in studies of wildlife nutrition. Hand-rearing protocols provide insights into dietary and training programs, but less information is available on disease management. In young ruminants, thiamin (Vitamin B1) deficiency is a particularly important disease that is treatable early in the disease process, but otherwise can be fatal. In this husbandry report, we describe a case of suspected thiamin deficiency in a hand-reared calf (Rangifer tarandus granti) that resulted in clinical signs of polioencephalomalacia and persisted for > 3 months. We attempted treatment with thiamin injections; injections resolved clinical signs of disease, but clinical signs of disease returned once injections stopped. After > 2 months of thiamin injections, the caribou calf received a rumen transfaunation from a fistulated moose (Alces alces) housed at the same facility. Following rumen transfaunation, we did not observe signs of thiamin deficiency. The calf outgrew other females in the cohort initially and shows no long-term effects of thiamin deficiency or polioencephalomalacia. We recommend rumen transfaunation when thiamin deficiency is suspected and does not resolve with thiamin injections alone. We also recommend heterospecific donors if conspecific donors are not available.

Conservation breeding programs can save species from extinction by establishing assurance populations that provide individuals for achieving species recovery goals in the wild. However, keeping animals in human care can result in the selection of phenotypes that may be suboptimal for post-release survival and reproduction. It is therefore essential that conservation breeding programs provide animals with naturalistic conditions that facilitate the performance of species-typical behaviors, an endeavor that is also a vital aspect of animal welfare. Here, we describe how we established a conservation breeding program for the 'Akikiki (Oreomystis bairdi), a Hawaiian honeycreeper that is facing imminent extinction in the wild. We share how we utilized the species' native habitat as a template for developing husbandry practices with a primary focus on how we simulate wild environmental conditions in enclosures, mimic naturalistic foraging experiences, and facilitate pair bonding and parental breeding behaviors.

For large felids in the wild, intervals between feeding events are irregular since these depend on prey availability and individual hunting success. In contrast, many zoos feed their large felids on fixed schedules. Predictable feeding schedules could induce food anticipatory behavior, like pacing, and randomizing feeding schedules may reduce this anticipatory behavior. Furthermore, random feeding schedules create more variability in the animals environment, which may reduce frustration or boredom. This case study aimed to investigate the effects of a random feeding schedule on pacing behavior of captive Asiatic lions (Panthera leo persica) in the Rotterdam Zoo, The Netherlands. Study animals were observed directly under two treatments: "fixed feeding" (i.e., two fixed feeding days per week) and "random feeding" (i.e., two semi-randomly picked feeding days per week). Under the random feeding schedule, the mean pacing proportion of lions significantly decreased compared to the fixed feeding schedule. These findings suggest that a random feeding schedule could reduce pacing, either of anticipatory or stereotypic nature, in Asiatic lions. Random feeding schedules do pose a few logistic challenges, such as zookeeper schedules and transport or storage of feed. Nevertheless, random feeding could be a relatively inexpensive strategy to reduce pacing.

Maintaining a diverse gene pool is important in the captive management of zoo populations, especially in endangered species such as the pink pigeon (Nesoenas mayeri). However, due to the limited number of breeding individuals and relaxed natural selection, the loss of variation and accumulation of harmful variants is inevitable. Inbreeding results in a loss of fitness (i.e., inbreeding depression), principally because related parents are more likely to transmit a copy of the same recessive deleterious genetic variant to their offspring. Genomics-informed captive breeding can manage harmful variants by artificial selection, reducing the genetic load by avoiding the inheritance of two copies of the same harmful variant. To explain this concept in an interactive way to zoo visitors, we developed a sonification game to represent the fitness impacts of harmful variants by detuning notes in a familiar musical melody (i.e., Beethoven's Für Elise). Conceptually, zoo visitors play a game aiming to create the most optimal pink pigeon offspring in terms of inbreeding depression. They select virtual crosses between pink pigeon individuals and listen for the detuning of the melody, which represents the realised load of the resultant offspring. Here we present the sonification algorithm and the results of an online survey to see whether participants could identify the most and least optimal offspring from three potential pink pigeon offspring. Of our 98 respondents, 85 (86.7%) correctly identified the least optimal offspring, 73 (74.5%) correctly identified the most optimal, and 62 (63.3%) identified both the most and least optimal offspring using only the sonification.

It has been suggested repeatedly that zoo-kept giant anteaters (Myrmecophaga tridactyla) have higher body masses than their free-ranging conspecifics. Here, we assess this hypothesis by comparing body mass data of 184 female and 173 male individuals kept in zoos to published and unpublished data of free-ranging animals (n = 215). In zoos, the average adult body mass of all individuals was 45.9 ± 9.6 kg (range 19.2-72.6 kg), whereas body mass for free-ranging specimens was 33.0 ± 2.3 kg (21-45.5 kg). Among those zoo animals in which a sufficient number of subsequent intra-annual measures had been taken, we assessed visually whether regular, annual fluctuations in body mass were evident. We observed regular, likely seasonal, cycles in body mass, which (i) may be plausibly attributed to ambient temperature changes that affect the body temperature of anteaters, and (ii) would likely not have occurred if the animals were affected by obesity. Additionally, we explain our hypothesis that in the case of giant anteaters, the discrepancy in body mass between natural habitats and zoos most likely is not indicative of a generally obese population in zoos, as is typically concluded in the case of similar comparisons in primates, but represents an unleashing of the full growth potential of the species by conditions of optimal energy and nutrient provision. Future recording of not only body mass but also body dimensions is recommended to better compare the body condition of free-ranging and zoo-managed individuals.

While translocations of white rhinoceroses have become an important conservation tool, dehydration during long-distance transports has been identified as a welfare concern. Intravenous (iv) fluid administration might therefore be useful to mitigate dehydration; however, special requirements need to be met to make iv fluid administration suitable for large, wild rhinoceroses during transport. Requirements include a portable and robust system that is capable of delivering high flow rates, is easy to set up, and remains patent and operating for long periods of time while allowing the animals to freely stand or lay down in the transport crates. Due to the lack of suitable fluid administration systems, we developed a custom-made system consisting of 8 L drip bags, a three-part, 4.4-m-long, large bore and partially coiled administration set, and a robust, battery-operated infusion pump, which allowed us to successfully administer iv fluids at a maintenance rate of 1-2 mL/kg/h to eight rhinoceroses for 24 h during a mock transport. While iv fluid administration in transported rhinoceroses is time intensive and the large amount of drip bags required during lengthy transports might pose a limitation, the developed system may be useful for the long-distance transport of small groups of rhinoceroses. Furthermore, this system would be of value for injured or sick rhinoceroses, which require parenteral fluid therapy when commercially available infusion pumps cannot provide the large fluid volumes needed.

While housing nonbreeding all-male social groups of African lion (panthera leo) is a necessary part of managing this polygynous species ex situ, resulting intraspecific agonistic behavior can negatively impact animal welfare and guest experience, undermining two primary objectives of modern zoological gardens. Improvest is a gonadotropin releasing factor analog-diphtheria toxoid conjugate marketed for temporary immunological castration which has proven successful in reducing aggression in other zoo-housed species. To the authors' knowledge, the use of this technique has not been described in male African lions; reticence to use GnRH agonists may stem from concern about phenotypic effects (mane loss) and zoo visitor perception. We describe the use of Improvest in conjunction with other management changes to manage agonism in a coalition of African lions (3.0) housed at the Oakland Zoo. Daily agonism scores were calculated via animal care staff records, fecal testosterone levels were measured, and monthly photos were taken to monitor phenotypic changes. While agonism scores varied seasonally in three pretreatment years, a significant (p < 0.05) reduction in the frequency of agonistic behavior began within 2 months of initial treatment. Two lions showed testosterone suppression within 2 months of receiving the first vaccine, while the third showed suppression beginning in the period 4 months after the first vaccine. Mane loss occurred in all three lions, and time to mane regrowth varied between individuals. Improvest, combined with other management strategies, decreased overall fecal testosterone and intraspecific agonism in these lions, and may be an effective tool in other male coalitions.

Over the past several decades, facultative parthenogenesis (FP)-the ability of a sexually reproducing species to reproduce asexually-in vertebrates has been removed from the realm of obscurity and placed firmly in a position where it warrants focused scientific attention. Likely fueled by increased recognition of the trait, the availability of molecular tools capable of disentangling FP from long-term sperm storage, and the availability of potential cases originating from both zoological and private collections, a wealth of papers has been published revealing the diversity of vertebrate systems in which FP occurs. Specifically, cases have been reported in squamate reptiles (lizards and snakes), crocodiles, birds, and elasmobranch fishes (sharks, rays, and skates). Nonetheless, gaps remain in species documentation, and it is important to analyze and report on new cases. In this paper, we provide a DNA-based analysis confirming FP in a zoo-maintained northern water snake, Nerodia sipedon, a viviparous natricine species that is common and widely distributed in North America. Additionally, we provide information on the sexual development and health of the male parthenogen. Encouragingly, zoological institutions, aquaria, university laboratories, and private collections continue to be rich sources for the further study and documentation of FP in vertebrate species, advancing our understanding of this reproductive trait.