Reptiles are held at wildlife parks and zoos for display and conservation breeding programs and are increasingly being kept as pets. Reliable indicators of welfare for reptiles need to be identified. Current guidelines for the captive management of reptiles utilize resource-based, rather than animal-based indicators; the latter being a more direct reflection of affective state. In this paper we review the literature on welfare assessment methods in reptiles with a focus on animal-based measures. We conclude that, whilst a number of physiological and behavioral indicators of welfare have been applied in reptiles, there is need for further validation of these methods across the diversity of species within the Class. Methods of positive welfare state assessment are comparatively understudied and need elucidation. Finally, we examine some widely-used welfare assessment tools in mammals and explore the application of the Welfare Quality^® Protocol to the endangered pygmy blue-tongue skink, Tiliqua adelaidensis. We propose that this framework can form the basis for the development of taxon-specific tools with consideration of species-specific biology.

Zoos are increasingly implementing formalized animal welfare assessment programs to allow monitoring of welfare over time, as well as to aid in resource prioritization. These programs tend to rely on assessment tools that incorporate resource-based and observational animal-focused measures. A narrative review of the literature was conducted to bring together recent studies examining welfare assessment methods in zoo animals. A summary of these methods is provided, with advantages and limitations of the approaches presented. We then highlight practical considerations with respect to implementation of these tools into practice, for example scoring schemes, weighting of criteria, and innate animal factors for consideration. It is concluded that there would be value in standardizing guidelines for development of welfare assessment tools since zoo accreditation bodies rarely prescribe these. There is also a need to develop taxon or species-specific assessment tools to complement more generic processes and more directly inform welfare management.

There is an increasing focus on evidence-based welfare assessment by animal care staff in zoos, along with a strong interest in animal welfare by the zoo-visiting public, to the extent that this can influence their choice of institutions to visit. Regulatory oversight of animal welfare standards continues to strengthen across many jurisdictions. Zoos are increasingly formalizing their practices with the development and refinement of evidence-based welfare assessment tools. There has been a drive for welfare assessment tools to comprise both resource-based and animal-based measures. However, animal-based indicators are not always well characterized, in terms of their nature and whether they infer a positive or negative affective state. This is especially so for reptiles, which are often considered behaviorally inexpressive and are under-researched. In this study, a Delphi consultation approach was used to gather expert opinion on the suitability of potential animal-based indicators of welfare for inclusion in a welfare assessment tool across four families of reptiles: Agamidae, Chelidae, Pythonidae, and Testudinidae. Two rounds of online surveys were conducted eliciting responses from a global group of professionals who work with reptiles. In the first survey, respondents were provided with an author-derived list of potential animal-based indicators for consideration of their validity and practicality as welfare indicators. The indicators were refined for the second survey including only those indicators that were considered valid or practical on the first survey (≥4 on a 5-point Likert scale), and that achieved ≥70% consensus amongst experts. In the second survey, respondents were asked to re-evaluate the reliability and practicality of the indicators and to rank them on these facets. Eight to ten assessment indicators for each family of reptiles were identified from Survey 2. These indicators were often health related, for example, presence of oculo-nasal discharge or wounds. However, some true behavioral indicators were identified, such as showing species-specific interest and alertness. These indicators should now be incorporated into taxon-tailored welfare assessment tools for trial and validation in captive reptile populations. This study provides a next step towards developing reptile-specific animal welfare assessment tools for these often-overlooked animals.

Macropod progressive periodontal disease (MPPD) is a necrotizing, polymicrobial, inflammatory disease commonly diagnosed in captive macropods. MPPD is characterized by gingivitis associated with dental plaque formation, which progresses to periodontitis and then to osteomyelitis of the mandible or maxilla. However, the underlying microbial causes of this disease remain poorly understood. In this study, we collected 27 oral plaque samples and associated clinical records from 22 captive Macropodidae and Potoroidae individuals that were undergoing clinical examination at Adelaide and Monarto Zoos in South Australia (15 healthy, 7 gingivitis and 5 periodontitis-osteomyelitis samples). The V3-V4 region of the 16S ribosomal RNA gene was sequenced using an Illumina Miseq to explore links between MPPD and oral bacteria in these animals. Compositional differences were detected between the microbiota of periodontitis-osteomyelitis cases compared to healthy samples (p-value with Bonferroni correction < 0.01), as well as gingivitis cases compared to healthy samples (p-value with Bonferroni correction < 0.05) using Permutational Multivariate Analysis of Variance (PERMANOVA). An overabundance of Porphyromonas, Fusobacterium, and Bacteroides taxa was also identified in animals with MPPD compared to healthy individuals using linear discriminant analysis effect size (LEfSe; p = < 0.05). An increased abundance of Desulfomicrobium also was detected in MPPD samples (LEfSe; p < 0.05), which could potentially reflect differences in disease progression. This is the first microbiota analysis of MPPD in captive macropods, and these results support a polymicrobial pathogenesis of MPPD, suggesting that the microbial interactions underpinning MPPD may be more complex than previously documented.

In the 2019–2020 Australian bushfires, Kangaroo Island, South Australia, experienced catastrophic bushfires that burnt approximately half the island, with an estimated 80% of the koala population lost. During and after the event, rescued koalas were triaged at a designated facility and a range of initial data were recorded including rescue location and date, sex, estimation of age, body condition and hydration, and assessment of burn severity (n = 304 records available). Koalas were presented to the triage facility over a span of 10 weeks, with 50.2% during the first 14 days of the bushfire response, the majority of which were rescued from regions of lower fire severity. Burns were observed in 67.4% of koalas, with the majority (60.9%) classified as superficial burns, primarily affecting the limbs and face. Poor body condition was recorded in 74.6% of burnt koalas and dehydration in 77.1%. Negative final outcomes (death or euthanasia, at triage or at a later date) occurred in 45.6% of koalas and were significantly associated with higher mean burn score, maximum burn severity, number of body regions burnt, poor body condition score, and dehydration severity. The findings of this retrospective study may assist clinicians in the field with decision making when triaging koalas in future fire rescue efforts.

A sarcomatoid carcinoma was diagnosed in the lung of a 10-year-old captive Egyptian fruit bat (Rousettus aegyptiacus). Both carcinomatous and sarcomatous cytologic phenotypes were identified histologically. Cells of both types stained positive for pancytokeratin and S-100. Stromal cells stained positively for muscle actin. No staining for vimentin was noted in either neoplastic or normal internal control tissues. To the authors' knowledge, this is the first report of a pulmonary sarcomatoid carcinoma in a bat, and only the third report of sarcomatoid carcinoma outside the human literature.