Captive Husbandry Research Articles

A RETROSPECTIVE ANALYSIS OF MORBIDITY AND MORTALITY IN THE CAPTIVE LEADBEATER'S POSSUM (GYMNOBELIDEUS LEADBEATERI) POPULATION FROM 1970 TO 2021.

The Leadbeater's possum (Gymnobelideus leadbeateri) is a critically endangered nocturnal marsupial with a restricted range in the Central Highlands of Victoria, Australia. There are two genetically distinct populations divided by location: highland and lowland. Lowland possums exist in one remnant swamp forest and entered captivity in 2012 when ∼60 individuals remained. Today, with less than 20 lowland individuals remaining, any information that informs the yet-unsuccessful breeding program is critical. This study encompasses a retrospective analysis of the causes of mortality and significant histological lesions in captive highland and lowland individuals across seven institutions internationally from 1970 to 2021. During this time, 245 possums lived in captivity. Postmortem records exist for 99 animals, including 349 histopathology diagnoses from 80 reports and 264 gross necropsy diagnoses from 78 reports. Diagnoses were assigned into two categories based on the importance to the individual (causing death or morbidity to a single animal [n = 194]), or importance to the wider population (causing death or morbidity to more than one animal or was related to reproduction [n = 155]). Individual animals had multiple diagnoses, which were tallied as individual data points. Renal disease was diagnosed 57 times; the most common finding was chronic nephropathy (43/57). Cardiovascular disease was diagnosed 33 times; atherosclerosis associated with obesity was common (n = 10/33). Both categories suggest causal association with captive husbandry but elicit no comment on the lack of success of the breeding program. Reproductive disease was diagnosed 36 times in 24 animals (14 females and 10 males). In females, 11 cases of uterine inflammation and associated clinical signs were associated with ascending infection or neoplasia. Of the seven lowland male possums with mortality data, five were infertile (azoospermia or testicular atrophy). More investigation into the reproductive health of this population is indicated to understand the lack of success in the current breeding program.

Friend or foe? Using eye-tracking technology to investigate the visual discrimination ability of giant pandas.

The role that visual discriminative ability plays among giant pandas in social communication and individual discrimination has received less attention than olfactory and auditory modalities. Here, we used an eye-tracker technology to investigate pupil fixation patterns for 8 captive male giant pandas Ailuropoda melanoleuca. We paired images (N = 26) of conspecifics against: 1) sympatric predators (gray wolves and tigers), and non-threatening sympatric species (golden pheasant, golden snub-nosed monkey, takin, and red panda), 2) conspecifics with atypical fur coloration (albino and brown), and 3) zookeepers/non-zookeepers wearing either work uniform or plain clothing. For each session, we tracked the panda's pupil movements and measured pupil first fixation point (FFP), fixation latency, total fixation count (TFC), and duration (TFD) of attention to each image. Overall, pandas exhibited similar attention (FFPs and TFCs) to images of predators and non-threatening sympatric species. Images of golden pheasant, snub-nosed monkey, and tiger received less attention (TFD) than images of conspecifics, whereas images of takin and red panda received more attention, suggesting a greater alertness to habitat or food competitors than to potential predators. Pandas' TFCs were greater for images of black-white conspecifics than for albino or brown phenotypes, implying that familiar color elicited more interest. Pandas reacted differently to images of men versus women. For images of women only, pandas gave more attention (TFC) to familiar combinations (uniformed zookeepers and plain-clothed non-zookeepers), consistent with the familiarity hypothesis. That pandas can use visual perception to discriminate intra-specifically and inter-specifically, including details of human appearance, has applications for panda conservation and captive husbandry.

Amphibian Dermatology.

Amphibians are susceptible to a multitude of skin disorders, many of which can appear grossly similar. The most common clinical presentations include hyperemia, discoloration, dermal mass, ulceration, and necrosis. Many amphibian skin diseases are related to captive husbandry. The diagnostic process starts with environmental evaluations, a full history, physical examination and sampling for direct observation, histology, polymerase chain reaction testing, and bacterial and fungal culture. This review emphasizes the main conditions encountered in amphibian dermatology.

Feeding, mating and animal wellbeing: new insights from phylogenetic comparative methods.

Feeding, mating and animal wellbeing: new insights from phylogenetic comparative methods.

Risk factors for stereotypic behaviour in captive ungulates.

Behavioural needs are highly motivated actions critical to a species survival and reproduction. Prolonged restriction of these behaviours can lead to stereotypic behaviours (SB) in captive animals, and this is particularly common in ungulate species. While risk factors for SB have been suggested for some ungulates, no study has integrated these findings to identify which aspects of ungulates' wild behavioural biology and captive husbandry are potential drivers for SB across this clade. We collated SB data from 15 236 individuals across 38 ungulate species from 95 sources, and determined species wild/free-ranging behaviour from 559 additional studies. Bayesian-phylogenetic statistical methods showed that ungulate behavioural needs relating to foraging and mating are particularly affected by captive environments, with promiscuous and browsing species showing the greatest prevalence of SB. Concentrate-only diets and lack of ad libitum feed substrates were also associated with high SB prevalence. This study identifies which ungulates are better suited to captive environments and which species require targeted husbandry, enrichment and breeding protocols in order to meet their behavioural needs. Our approach of applying Bayesian-phylogenetic inference to factors influencing SB within a clade can be used to identify other intrinsic and extrinsic risk factors of reduced animal health and welfare.

Pdf 03. Sexually dimorphic growth and maturity in captive mountain chicken frogs Leptodactylus fallax

ABSTRACT - Sexual dimorphism is commonly encountered in amphibians. Its presence and its ontogeny in a given species has implications for ecology, conservation and captive husbandry. We monitored changes in length and mass of captive mountain chicken frogs Leptodactylus fallax. Initially, sexes were no different in snout-vent length or mass, but by about 17 months after metamorphosis females became significantly larger and heavier than males. Diverging growth trajectories between male and female frogs appeared to coincide with the development of secondary sexual characters in males, indicating sexual maturity, while female frogs did not produce nests until the following breeding season, suggesting later reproductive maturity. The absence of similar dimorphism in other large leptodactylids suggests that its presence in L. fallax may be linked to its unique and energy-intense reproductive strategy, which involves extended maternal provisioning of their young.

Assessment of conservations actions for the critically endangered spotted handfish (Brachionichthyidae), following curation of data collected by multiple investigators into a long-term time-series

Multi-decadal datasets for endangered species that track both populations and performance of management interventions are rare. One such dataset is for the critically endangered Spotted handfish, a species which has been used as a conservation model for the most endangered of the marine bony fish families the Brachionichthyidae. We assessed a 23-year, multi-site, time-series of population density surveys for the spotted handfish as well as a conservation intervention, the planting of ∼ 14,000 artificial spawning habitats (ASH). Data ownership spanned multiple Principal Investigators (PIs) and key data and covariates, such as monitoring and interventions, were often documented within personal files and difficult to access grey literature. We consolidated and curated these data, identifying gaps in the time-series and their causes and isolating confounding factors before we assessed population trends and the effectiveness of ASH planting. Both funding gaps and the 2020 Covid-19 lockdown produced breaks in the time-series. Breeding season observations mostly occurred in the early part of the dataset and there was also a change in method that needed to be considered when interpretating the time-series. There was an overall decline in fish observed between 1997 and 2019 but, at least since 2014, there has been stabilisation of the population. Local populations of spotted handfish can either be highly dynamic or relatively stable but population increases were linked to the long-running, conservation intervention of planting ASH. As local populations can be dynamic, the functional life span of the ASH is limited and threats to the species - chronic, stochastic and climate - are ongoing, spotted handfish may be a ‘conservation reliant’ species that require annual site-specific monitoring, insitu interventions and existu captive husbandry.

Overlooked and Under-Studied: A Review of Evidence-Based Enrichment in Varanidae

Enrichment has become a key aspect of captive husbandry practices as a means of improving animal welfare by increasing environmental stimuli. However, the enrichment methods that are most effective varies both between and within species, and thus evaluation underpins successful enrichment programs. Enrichment methods are typically based upon previously reported successes and those primarily with mammals, with one of the main goals of enrichment research being to facilitate predictions about which methods may be most effective for a particular species. Yet, despite growing evidence that enrichment is beneficial for reptiles, there is limited research on enrichment for Varanidae, a group of lizards known as monitor lizards. As a result, it can be difficult for keepers to implement effective enrichment programs as time is a large limiting factor. In order for appropriate and novel enrichment methods to be created, it is necessary to understand a species’ natural ecology, abilities, and how they perceive the world around them. This is more difficult for non-mammalian species as the human-centered lens can be a hinderance, and thus reptile enrichment research is slow and lagging behind that of higher vertebrates. This review discusses the physiological, cognitive, and behavioral abilities of Varanidae to suggest enrichment methods that may be most effective.

Captive husbandry and breeding of the Nguru spiny pygmy chameleon Rhampholeon acuminatus

The Nguru spiny pygmy chameleon (Rhampholeon acuminatus) is endemic to the Nguru mountains in Tanzania. It is assessed as Critically Endangered and is collected from the wild for the pet trade. An ex-situ population of this species was recently established at The Wild Planet Trust, Paignton Zoo, in the hope of learning more about the husbandry and biology of this species. We report on the captive husbandry of adults and the successful breeding, hatching and rearing of juveniles. Females carried four eggs but laid them in pairs. When eggs were incubated at 19.2-22.8 °C, hatchlings emerged roughly 180 days after laying. The hatchlings had a total length of about 30 mm and weighed 0.2-0.3 g. To our knowledge, this is the first published account of captive breeding for this species. The husbandry methods described could be used to establish populations of this and other Rhampholeon species in captivity, which in turn would reduce the demand for wild caught (Rhampholeon), as well as inform future conservation breeding programmes for this species.

FIRST REPORT ON THE FEEDING BEHAVIOR OF EARLESS MONITOR, LANTHANOTUS BORNEENSIS AND ITS PREDATION ON RICE FIELD FROG, FEJERVARYA LIMNOCHARIS IN A CAPTIVE ENVIRONMENT

Being endemic to Borneo, the Earless monitor, Lanthanotus borneensis (Steindachner, 1878) is rarely found in its habitats due to its cryptic behavior. We provide care for confiscated animals in the Reptile House of Museum Zoologicum Bogoriense (MZB) in Cibinong, West Java, Indonesia since 2014. Little is known on its natural prey but from scattered descriptive reports. This study is aimed at documenting the feeding behavior of ten captive Earless monitors and events of predation on frogs. We set up two experiments, one with meat of Rice Field Frog, Fejervarya limnocharis, and the other with live frog of the same species. Our recorded observations ran for four weeks for the frog meat feeding experiment and followed by the frog predation experiment. Our results showed that lizards constantly accepted frog meat. Lizards tended to feed before sunset for a short period of time on the muddy soil surface, although a few individuals inconsistently fed under water. The average body mass for these lizards increased by 4.29 g and average SVL by 0.45 cm. We recorded predation on frogs in three out of ten individuals observed during this study. If F. limnocharis is confirmed to occur in the natural habitats of L. borneensis, it is possible that this frog species is among the natural prey for Earless monitors. Further studies on its natural diets should be conducted to gain in-depth knowledge essential for generating effective captive husbandry for this nationally protected species in Indonesia.

Two additional specimens of Naja (Boulengerina) nana (Serpentes: Elapidae) with notes on captive husbandry and behaviour

Two additional specimens of Naja (Boulengerina) nana (Serpentes: Elapidae) with notes on captive husbandry and behaviour

Investigating the effect of social grouping on the behaviour of captive leopards

Big cats are both popular and well represented in zoological collections worldwide, and there is considerable interest in evidence-based studies to develop best practice husbandry guidelines. The majority of big cat species, including the leopard Panthera pardus are typically solitary in the wild, whereas in zoos they are sometimes maintained as pairs or larger groups. This study investigates the behaviour of six leopards housed as a trio, a pair, and singleton in the Parco Faunistico Valcorba, Italy. Behavioural data were collected using instantaneous focal sampling at one-minute intervals with continuous recording for events, and Electivity Index was used to assess the use of each enclosure zone by individual leopards. Poisson regressions were used to determine whether individual leopard, weather and decibel levels were predictors of behaviour change. Overall, the Poisson regressions were significant for all behaviours except allogrooming. Both affiliative and aggressive behaviours were observed most frequently in the recently mixed trio, and these were often initiated by the male. By contrast, the pair of leopards rarely interacted with one another. Irrespective of condition, leopards tended to overutilize a few key zones in their exhibits and did not use their enclosures evenly. However, there were differences in zone overlap: the pair housed leopards appeared to use different zones to one another, whilst the trio of leopards appeared to use similar zones. These data suggest that group housing may be a viable housing strategy for leopards, provided that the animals are given the opportunity to avoid each other should they choose to do so. However, personality and compatibility of leopards is likely to be a confounding factor that must be considered when developing group-housing husbandry strategies. Further studies with a focus on group housing of other felid species would be valuable to evidence-base their captive husbandry.

Full Spectrum Lighting Induces Behavioral Changes and Increases Cortisol Immunoreactivity in Captive Arachnids

ABSTRACT The use of full spectrum illumination, including ultraviolet (UV), during captive husbandry of arachnids is common practice. The effect of this on captive arachnids has not been previously investigated. Comparison of key behavioral changes and hemolymph cortisol immunoreactivity was undertaken with and without full spectrum lighting. King baboon spiders, Pelinobius muticus and Indian giant scorpions, Heterometrus swammerdami were selected for the study. Both organisms spent all their time hidden when exposed to full spectrum light compared to low-level ambient light except for one instance. There was no significant difference in burrowing and webbing in P. muticus when exposed to full spectrum lighting. There was a decrease in the number of behaviors or postures expressed in full spectrum lighting compared to ambient light for both species. Cortisol immunoactivity of both species were significantly elevated after exposure to full spectrum lighting. This study provides the first evidence of detectable cortisol immunoactivity in arachnid hemolymph. These levels changed in response to full spectrum illumination and were linked to behavioral changes. This suggests that a common husbandry practice may be detrimental to arachnids.

Cranial morphology of captive mammals: a meta-analysis

BackgroundCaptive facilities such as zoos are uniquely instrumental in conservation efforts. To fulfill their potential as bastions for conservation, zoos must preserve captive populations as appropriate proxies for their wild conspecifics; doing so will help to promote successful reintroduction efforts. Morphological changes within captive populations may be detrimental to the fitness of individual animals because these changes can influence functionality; thus, it is imperative to understand the breadth and depth of morphological changes occurring in captive populations. Here, we conduct a meta-analysis of scientific literature reporting comparisons of cranial measures between captive and wild populations of mammals. We investigate the pervasiveness of cranial differences and whether cranial morphological changes are associated with ecological covariates specific to individual species, such as trophic level, dietary breadth, and home range size.ResultsCranial measures of skull length, skull width, and the ratio of skull length-to-width differed significantly between many captive and wild populations of mammals reported in the literature. Roughly half of captive populations differed from wild populations in at least one cranial measure, although the degree of changes varied. Carnivorous species with a limited dietary breadth displayed the most consistent changes associated with skull widening. Species with a more generalized diet displayed less morphological changes in captivity.ConclusionsWild and captive populations of mammals differed in cranial morphology, but the nature and magnitude of their cranial differences varied considerably across taxa. Although changes in cranial morphology occur in captivity, specific changes cannot be generalized for all captive mammal populations. The nature of cranial changes in captivity may be specific to particular taxonomic groups; thus, it may be possible to establish expectations across smaller taxonomic units, or even disparate groups that utilize their cranial morphology in a similar way. Given that morphological changes occurring in captive environments like zoos have the potential to limit reintroduction success, our results call for a critical evaluation of current captive husbandry practices to prevent unnecessary morphological changes.

The effects of two calcium supplementation regimens on growth and health traits of juvenile mountain chicken frogs (Leptodactylus fallax)

The mountain chicken frog (Leptodactylus fallax) is among the 42 % of amphibians threatened with extinction and is dependent upon ex situ populations to recover in the wild. Amphibian captive husbandry is not fully understood and empirical data are required to optimise protocols for each species in captivity. Calcium metabolism and homeostasis are areas of importance in captive husbandry research and have been identified as a challenge in maintaining ex situ populations of L. fallax. We trialled two frequencies (twice and seven times weekly) of calcium supplementation via dusting of feeder insects in two groups of L. fallax juveniles and measured growth and health effects through morphometrics, radiography, ultrasonography and blood and faecal analysis over 167 days, followed by a further 230 days of monitoring on an intermediate diet informed by the initial dataset. We showed that supplementation treatment did not affect growth or health status as measured through blood analysis, radiography and ultrasonography. More frequent supplementation resulted in significantly more radiopaque endolymphatic sacs and broader skulls. Frogs fed more calcium excreted twice as much calcium in their faeces. The intermediate diet resulted in previously lower supplementation frogs approximating the higher supplementation frogs in morphometrics and calcium stores. Comparison with radiographic data from wild frogs showed that both treatments may still have had narrower skulls than wild animals, but mismatching age class may limit this comparison. Our data may be used to inform dietary supplementation of captive L. fallax as well as other amphibians.

Specialised for the Swamp, Catered for in Captivity? A Cross-Institutional Evaluation of Captive Husbandry for Two Species of Lechwe.

Simple SummaryLechwe are social antelope adapted to wetland environments that can perform a ritualised courtship display. Although commonly housed in zoos, there is little published information available to guide their management. This study aimed to understand current husbandry practice for southern and Nile lechwe housed in North American and European institutions. A survey was sent to holders of these species, with questions addressing group demographics, enclosure characteristics, diet, enrichment, and occurrence of abnormal behaviours. Results showed that captive lechwe herds consisted of a similar ratio of male to females compared to wild herds, but there may be a limit to the number of male animals available to females at any one time. Lechwe enclosures typically featured wetland areas but these were rarely managed and there were often limited areas of vegetation for cover. The diets provided to lechwe differed when compared to existing husbandry guidelines but did not significantly differ between sampled zoos (in terms of ingredients commonly used). Abnormal behaviours were reported at several zoos but no specific causal factor was identified. This research provides a starting point for further study of the husbandry requirements of these specialised ungulates and considers the role of ecological information to the management of captive wild animals.Lechwe are specialised wetland antelope that can have a strict social hierarchy or perform lekking during breeding. The southern lechwe (Kobus leche) and the Nile lechwe (K. megaceros) are both found in zoos globally, but little research is available to support husbandry decisions. The aim of this research was to investigate current housing and husbandry used for these lechwe across North American and European zoos. A survey was distributed to holders in 2018 and information on 33 herds (18 Nile and 15 southern) was collected. The survey focussed on population demographics, enclosure size, biologically relevant exhibit features, mixed-species holdings, nutrition, use of environmental enrichment and performance of abnormal repetitive behaviours. Results showed that lechwe were housed in herds with similar sex ratios to wild counterparts but with a potential lack of opportunity to lek. Many zoos provided wetland, but this was rarely actively managed, and not all zoos provided cover for hiding and retreat. Current feeding practice differed significantly compared to available antelope husbandry guidelines. No consistency in amounts of pellet, forage or produce provided to lechwe across institutions was found. Abnormal repetitive behaviour was noted by several zoos, but no significant predictor of such behaviour could be identified. Despite some identifiable recognition of ecology informing lechwe management, it is important that evidence-based husbandry decisions are made based on a species’ evolutionary pathway and ecological needs and some fundamental features of lechwe husbandry do not always correlate with the adaptive traits of a specialised wetland ungulate.

Integrating Gut Bacterial Diversity and Captive Husbandry to Optimize Vulture Conservation.

Endangered species recovery plans often include captive breeding and reintroduction, but success remains rare. Critical for effective recovery is an assessment of captivity-induced changes in adaptive traits of reintroduction candidates. The gut microbiota is one such trait and is particularly important for scavengers exposed to carcass microbiomes. We investigated husbandry-associated differences in the gut microbiota of two Old World vulture species using 16S RNA gene amplicon sequencing. Increased abundance of Actinobacteria occurred when vultures were fed quail but not rat or chicken. Conversely, diet preparation (sanitization) had no effect, although bacterial diversity differed significantly between vulture species, likely reflective of evolved feeding ecologies. Whilst the relative lack of influence of a sanitized diet is encouraging, changes in bacterial abundance associated with the type of prey occurred, representing a dietary influence on host–microbiome condition warranting consideration in ex situ species recovery plans. Incorporation of microbiome research in endangered species management, therefore, provides an opportunity to refine conservation practice.

Differentiating captive and wild African lion (Panthera leo) populations in South Africa, using stable carbon and nitrogen isotope analysis

The international trade in lion (Panthera leo) products, particularly bone, has increased substantially over the last decade. The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) has established a zero-export quota for wild-origin lion bones. Whilst the trade of lion bone is permittable from captive-bred South African populations, there is no established method to differentiate between captive and wild-sourced lion derivatives in trade. This study acts as a preliminary investigation, by examining the stable carbon (δ13C) and nitrogen (δ15N) isotope composition of hair from wild and captive lion populations as well as wild prey animals in South Africa, to judge the accuracy and applicability of this method for future bone analysis. Isotopic values for δ15N are found to be significantly enriched in some wild populations, however it is not possible to discriminate between captive and wild populations using δ13C analysis alone. Using the classification algorithm k-Nearest Neighbour, the origin of simulated data was identified with 70% accuracy. When using the model to test the origin of seized samples, 63% were classified as of wild origin. Our study indicates the potential for stable isotope analysis to discriminate between captive and wild populations. Additional study of captive husbandry, and analysis of bone samples from populations of a known origin and feeding regime is recommended to improve the utility of this method for maintaining transparency in trade.

Captive husbandry and breeding of the reticulated glass frog, Hyalinobatrachium valerioi (Anura: Centrolenidae)

The reticulated glass frog (Hyalinobatrachium valerioi) from Central and South America is a species that has been widely collected from the wild for the pet trade. An ex situ population of this frog was recently established at Slimbridge Wetland Centre, UK, in the hope of learning more about the husbandry and biology of this species. We report on the captive husbandry of adults and the successful breeding and rearing of larvae to metamorphosis. Clutch size was 28 eggs. The eggs hatched at 15-18 days after laying and tadpoles reached a total length of 34 mm. The first individuals started metamorphosis 147 days after hatching at water temperatures of 22-28 °C. Hyalinobatrachium valerioi is still being collected from the wild for the international pet trade and to our knowledge this is the first documented breeding of this species in the UK. The husbandry methods described here could be used to breed this and other Hyalinobatrachium species in captivity and so reduce collecting from wild populations.

Microhabitat preference of the critically endangered golden mantella frog in Madagascar

The golden mantella (Mantella aurantiaca) is a critically endangered (CR) frog, endemic to the eastern rainforestsof Madagascar. Although the species is very popular in the pet trade and widely bred in captivity, its specific habitat requirements in the wild are poorly understood. Ten forested sites in the Moramanga district of Madagascar were surveyed for microhabitat and environmental variables, and the presence or absence of golden mantellas in quadrats positioned along transects in the vicinity of breeding sites. Mixed models were used to determine which variables best explained microhabitat use by golden mantellas. Sites where golden mantellas were found tended to have surface temperatures of 20-23 ˚C, UVI units at about 2.9, about 30 % canopy cover, and around 30 % herbaceous cover. Within sites, golden mantellas preferred microhabitats that had 70 % leaf litter coverage and relatively low numbers of tree roots. This information can be used to improve the identification and management of habitats in the wild, as well as to refine captive husbandry needs.