Toe Clipping of Amphibians and Reptiles: Science, Ethics, and the Law 1

Optimising recovery of DNA from minimally invasive sampling methods: Efficacy of buccal swabs, preservation strategy and DNA extraction approaches for amphibian studies

Studies in evolution, ecology and conservation are increasingly based on genetic and genomic data. With increased focus on molecular approaches, ethical concerns about destructive or more invasive techniques need to be considered, with a push for minimally invasive sampling to be optimised. Buccal swabs have been increasingly used to collect DNA in a number of taxa, including amphibians. However, DNA yield and purity from swabs are often low, limiting its use. In this study, we compare different types of swabs, preservation method and storage, and DNA extraction techniques in three case studies to assess the optimal approach for recovering DNA in anurans. Out of the five different types of swabs that we tested, Isohelix MS-02 and Rapidry swabs generated higher DNA yields than other swabs. When comparing storage buffers, ethanol is a better preservative than a non-alcoholic alternative. Dried samples resulted in similar or better final DNA yields compared to ethanol-fixed samples if kept cool. DNA extraction via a Qiagen™ DNeasy Blood and Tissue Kit and McHale's salting-out extraction method resulted in similar DNA yields but the Qiagen™ kit extracts contained less contamination. We also found that samples have better DNA recovery if they are frozen as soon as possible after collection. We provide recommendations for sample collection and extraction under different conditions, including budgetary considerations, size of individual animal sampled, access to cold storage facilities and DNA extraction methodology. Maximising efficacy of all of these factors for better DNA recovery will allow buccal swabs to be used for genetic and genomic studies in a range of vertebrates.

Comparing skin swabs, buccal swabs, and toe clips for amphibian genetic sampling, a case study with a small anuran (Acris blanchardi)

Multiple methods for collecting genetic samples from amphibians exist, each with their own implications for study design, animal welfare, and costs. Toe clipping is one common method, but there is ongoing debate regarding its potential detriment. Less invasive methods should be implemented, if efficacious, as amphibians are a particularly vulnerable vertebrate group. Skin and buccal swabbing are less invasive methods for genetic sampling, but the potential for contamination and a lower yield of DNA may exist. To compare these methods, we gathered skin swabs, buccal swabs, and toe clips from the same individuals of a relatively small anuran species, Blanchard's Cricket Frog (Acris blanchardi). We then compared DNA yield, DNA purity, amplification success rate, and genotypic data quality among sample types. We found toe clips and buccal swabs generated similar DNA yield and purity, with skin swabs yielding significantly less DNA of significantly lower purity than the other sample types. Amplification success rate was significantly higher using toe clips compared to the other sample types, though buccal swab samples amplified more readily than skin swabs. Genotypic data from toe clips and buccal swabs did not differ significantly in quality, but skin swab data quality was significantly lowest among sample types. Thus, skin swabbing could produce erroneous data in some situations, but buccal swabbing is likely an effective substitute to toe clipping, even for small species. Our results can help future researchers select which genetic sampling method might best suit their research needs.

Performance of different automatic photographic identification software for larvae and adults of the European fire salamander

For many species, population sizes are unknown despite their importance for conservation. For population size estimation, capture-mark-recapture (CMR) studies are often used, which include the necessity to identify each individual, mostly through individual markings or genetic characters. Invasive marking techniques, however, can negatively affect the individual fitness. Alternatives are low-impact techniques such as the use of photos for individual identification, for species with stable distinctive phenotypic traits. For the individual identification of photos, a variety of different software, with different requirements, is available. The European fire salamander (Salamandra salamandra) is a species in which individuals, both at the larval stage and as adults, have individual specific patterns that allow for individual identification. In this study, we compared the performance of five different software for the use of photographic identification for the European fire salamander: Amphibian & Reptile Wildbook (ARW), AmphIdent, I3S pattern+, ManderMatcher and Wild-ID. While adults can be identified by all five software, European fire salamander larvae can currently only be identified by two of the five (ARW and Wild-ID). We used one dataset of European fire salamander larval pictures taken in the laboratory and tested this dataset in two of the five software (ARW and Wild-ID). We used another dataset of European fire salamander adult pictures taken in the field and tested this using all five software. We compared the requirements of all software on the pictures used and calculated the False Rejection Rate (FRR) and the Recognition Rate (RR). For the larval dataset (421 pictures) we found that the ARW and Wild-ID performed equally well for individual identification (99.6% and 100% Recognition Rate, respectively). For the adult dataset (377 pictures), we found the best False Rejection Rate in ManderMatcher and the highest Recognition Rate in the ARW. Additionally, the ARW is the only program that requires no image pre-processing. In times of amphibian declines, non-invasive photo identification software allowing capture-mark-recapture studies help to gain knowledge on population sizes, distribution, movement and demography of a population and can thus help to support species conservation.

Differential recovery ability from infections by two blood parasite genera in males of a Mediterranean lacertid lizard after an experimental translocation

Different blood parasites can co-infect natural populations of lizards. However, our knowledge of the host's ability to recover from them (i.e., significantly reduce parasitemia levels) is scarce. This has interest from an ecological immunology perspective. Herein, we investigate the host recovery ability in males of the lizard Psammodromus algirus infected by parasite genera Schellackia and Karyolysus. The role of lizard hosts is dissimilar in the life cycle of these two parasites, and thus different immune control of the infections is expected by the vertebrate host. As Schellackia performs both sexual and asexual reproduction cycles in lizards, we expect a better immune control by its vertebrate hosts. On the contrary, Karyolysus performs sexual reproductive cycles in vectors, hence we expect lower immune control by the lizards. We carried out a reciprocal translocation experiment during the lizards' mating season to evaluate both parasitemia and leukocyte profiles in male lizards, being one of the sampling plots close to a road with moderate traffic. These circumstances provide a combination of extrinsic (environmental stress) and intrinsic factors (reproductive vs. immune trade-offs) that may influence host's recovery ability. We recaptured 33% of the lizards, with a similar proportion in control and translocated groups. Karyolysus infected 92.3% and Schellackia 38.5% of these lizards. Hosts demonstrated ability to significantly reduce parasitemia of Schellackia but not of Karyolysus. This suggests, in line with our predictions, a differential immune relationship of lizards with these parasites, at time that supports that parasites with different phylogenetic origins should be analyzed separately in investigations of their effects on hosts. Furthermore, lizards close to the road underwent a stronger upregulation of lymphocytes and monocytes when translocated far from the road, suggesting a putative greater exposure to pathogens in the latter area.

Plastron color patterns allows for individual photo-identification in two different chelonian species

Natural marks have increasingly been used as a tool for individual identification in capture-mark-recapture techniques. Photo-identification is a non-invasive alternative to traditional marking techniques, allowing individual recognition of species through time and space. We tested the APHIS (Automatic Photo Identification) software as a software capable of identifying individuals of Testudo hermanni (Gmelin, 1789) and Emys orbicularis (Linneaus, 1758) in different populations during capture-release sessions in the field based on plastron color patterns, since they can be used as natural marks for identification. For this individual identification, SPM (Spot Pattern Matching) and ITM (Image Template Matching) procedures were tested; achieving 100 % success of individuals recognized in both procedures and visually verified comparing the images. However, ITM procedure was more efficient at recognizing recaptures than SPM because ITM allowed faster recaptures verification, since most of the matches were directly placed on the first position on the candidates list. Previous studies have used photo-identification on freshwater or sea turtles, but never with terrestrial tortoise species. Consequently, it can be corroborated that APHIS is a competent and efficient software considering photo-identification of T. hermanni and E. orbicularis and can be applied with close species with similar and unique individual color patterns in their plastron.

Linking agricultural practices to lizard trophic behaviour: An ecological approach

Among intensive agricultural practices, pesticides, mowing, and heavy agricultural machineries have become an important tool to maximize harvesting and secure animal husbandry. However, they are also cause of agricultural ecosystem decline, often leading to degradation of key micro-habitat features for many species, higher predation risk and lower food availability. We investigated the diet and foraging ecology of the Italian wall lizard in agricultural areas to determine whether different management practices (conventional, organic, and control) can affect (i) the structure of the trophic niche of the species; (ii) prey diversity, the degree of individual specialization, and the overall population feeding strategy; (iii) lizards' health status. Faecal pellets were collected for diet composition analyses, while prey diversity in the environment was estimated by placing adhesive traps. Lizards' body condition did not differ among management type although males from control field resulted slightly larger than those from conventional and organic areas. The species showed a generalist (conventional and organic areas) and mixed (control area) feeding strategy with a preference for coleopterans. Although a different prey diversity was found in control areas compared to organic and conventional ones, diet composition and the importance of specific food items was similar among management types. This may suggest that management activities may have affected the overall prey availability and indirectly influenced lizard trophic behaviour. Our study provides a comprehensive knowledge on the feeding ecology of P. siculus in managed habitats, which may have useful implications for the overall conservation of lizards in agricultural environments.

Age structure and growth pattern of a high-altitude lizard population based on age determination by skeletochronology

Age determination provides crucial data regarding the life history of a species. Skeletochronology is considered to be a reliable method for age determination but is seldom applied to the genus Phrynocephalus (Agamidae) as it requires careful bone histological analysis to determine the formation of the lines of arrested growth (LAGs). We analyzed LAGs in different bones of Phrynocephalus vlangalii, a small, high-altitude lizard, and demonstrated that the phalanges are the best materials for skeletochronology in this species. We also found that the proximal half of the phalangeal diaphysis exhibits the most complete LAGs because of the unidirectional longitudinal growth of the phalange. Histologically, as the embryo bone that developed during the embryonic period was preserved even in very old individuals, no LAGs were eroded by endosteal resorption in the phalanges. The maximum age was 4 years for males and 5 years for females. It was determined that the age at maturity was 3 years for males and 2 or 3 years for females. On the basis of age determination, the age structures of both sexes were compared, and age-specific growth differences between the sexes were also analyzed. No differences in the snout-vent length were observed between sexes in any age group. However, the tail length of males aged 3 and above was significantly longer than that of females. Thus, the use of phalanges in the age determination of P. vlangalii is effective and can be widely applied to the ecological studies of this species as well as other small lizards.

Longitudinal effects of habitat quality, body condition, and parasites on colour patches of a multiornamented lizard

Abstract

Ontogeny is expected to be a determinant factor affecting production of colour patches in lizards, while immune challenges or sudden weight loss may impair the maintenance of pigment-based coloration within a breeding season. We translocated males of the lizard Psammodromus algirus between two sampling plots that differed in distance to a road, vegetation structure, and predator abundance. We analysed variation in spectral reflectance of their colour patches the same and the following year. The change in the reflectance of the lizard colour patches within the first breeding season was explained by the interaction between plot and treatment, but not body condition. The maintenance of the breeding coloration was impaired only in those males translocated close to the road, probably reflecting that it is a poor-quality habitat for P. algirus. The following year, lizards that produced a more elaborate coloration were those that increased their body condition and controlled some parasitic infections, although suffered an increase of others. This study shows that colour patch production is plastic in P. algirus. Lizards increasing parasites or losing weight reduced pigmentation, although habitat quality can cushion these negative effects on pigmentation. However, not all parasites constrain the investment in coloration. In fact, some increased in those lizards that allocated more pigments to colour patches. In conclusion, longitudinal studies following experimental manipulation can contribute to understand pigment allocation rules in lizards.

Significance statement

Pigments involved in colour patches of animals are limiting resources that can be reallocated off the skin to other functions. However, longitudinal evidence of this phenomenon is scarce in reptiles. We designed a manipulative mark-recapture experiment to investigate effects of habitat and parasitic infections on colour patch maintenance (within-year variation) and production (between-year variation) in male free-ranging lizards that were reciprocally translocated between two patches of habitat that differed in quality. During the first year, lizards translocated to the habitat with more predators and worse vegetation impoverished their coloration, while lizards translocated to the more favourable habitat maintained it despite all translocated lizards loose body condition. The next year we detected different effects on the coloration of three different parasites investigated, suggesting that coloration can reflect the virulence of the infections.

Phenological and intrinsic predictors of mite and haemacoccidian infection dynamics in a Mediterranean community of lizards

Ectotherms are vulnerable to environmental changes and their parasites are biological health indicators. Thus, parasite load in ectotherms is expected to show a marked phenology. This study investigates temporal host–parasite dynamics in a lizard community in Eastern Spain during an entire annual activity period. The hosts investigated were Acanthodactylus erythrurus, Psammodromus algirus and Psammodromus edwardsianus, three lizard species coexisting in a mixed habitat of forests and dunes, providing a range of body sizes, ecological requirements and life history traits. Habitat and climate were considered as potential environmental predictors of parasite abundance, while size, body condition and sex as intrinsic predictors. Linear models based on robust estimates were fitted to analyse parasite abundance and prevalence. Ectoparasitic mites and blood parasites from two haemococcidian genera were found: Lankesterella spp. and Schellackia spp. Habitat type was the only predictor explaining the abundance of all parasites, being mostly higher in the forest than in the dunes. The results suggest that particularities in each host–parasite relationship should be accounted even when parasites infect close-related hosts under the same environmental pressures. They also support that lizard parasites can be biomarkers of environmental perturbation, but the relationships need to be carefully interpreted for each host–parasite assemblage.

Fluctuating asymmetry as biomarker of pesticides exposure in the Italian wall lizards (Podarcis siculus)

The extensive use of pesticides in agricultural environments produces drastic effects on wildlife, hence the need for less invasive indicators of environmental stress to monitoring the impact of agriculture treatments on biological systems. Fluctuating asymmetry (FA), as measure of developmental instability, has recently been proposed as reliable biomarker of populations stress due to environmental disturbance. We investigate femoral pores (FP) and dorsal head shape (HS) traits in populations of the Italian wall lizard inhabiting agricultural environments to examine whether different pesticide exposures (conventional, organic and control) can cause distinctive degree of FA. High-resolution photographs of FP and HS were taken in the field with a digital camera. The number of FP were counted twice on both sides and HS was analysed using geometric morphometrics with 25 landmarks and 12 semilandmarks. Individuals under conventional management showed higher levels of FA compared to control ones, and females exhibited higher FA levels than males for the FP. However, no significant difference was found for the HS trait. Our study provided evidence that FA may have a real potential as biomarker of population stress in wall lizards, highlighting the importance in the choice of the experimental design and the traits adopted for estimating DI.

Age structure of a lizard along an elevational gradient reveals nonlinear lifespan patterns with altitude

Lifespan is one of the main components of life history. Shorter lifespans can be expected in marginal habitats. However, in the case of ectotherms, lifespan typically increases with altitude, even though temperature—one of the main factors to determine ectotherms’ life history—declines with elevation. This pattern can be explained by the fact that a shorter activity time favors survival. In this study, we analyzed how lifespan and other life-history traits of the lizard Psammodromus algirus vary along a 2,200 m elevational gradient in Sierra Nevada (SE Spain). Populations at intermediate altitudes (1,200–1,700 m), corresponding to the optimal habitat for this species, had the shortest lifespans, whereas populations inhabiting marginal habitats (at both low and at high altitudes) lived longest. Therefore, this lizard did not follow the typical pattern of ectotherms, as it also lived longer at the lower limit of its distribution, nor did it show a longer lifespan in areas with optimal habitats. These results might be explained by a complex combination of different gradients along the mountain, namely that activity time decreases with altitude whereas food availability increases. This could explain why lifespan was maximum at both high (limited activity time) and low (limited food availability) altitudes, resulting in similar lifespans in areas with contrasting environmental conditions. Our findings also indicated that reproductive investment and body condition increase with elevation, suggesting that alpine populations are locally adapted.

Immune response declines with age in a wild lizard

The immune system allows animals to survive the constant attacks of pathogens. Although it is essential for survival and fitness, the performance of the immune system can decline with age (a process known as immunosenescence), which may be responsible for the increased mortality of older individuals. Only a few studies have investigated the effect of age on the immune system in reptiles, and no evidence of immunosenescence has yet been reported in lizards. In a wild population of Dickerson’s collared lizards (Crotaphytus dickersonae), we evaluated the effect of age (estimated by skeletochronology) on the male’s immune response to a novel antigen (phytohaemagglutinin). We found a strong negative relationship between immune response and age, the first evidence of immunosenescence in a lizard. Our results show that immunosenescence can occur even in relatively short-lived reptiles and underline the importance of age on performance in fitness-related traits.

High detectability with low impact: Optimizing large PIT tracking systems for cave-dwelling bats

Passive integrated transponder (PIT) tag technology permits the "resighting" of animals tagged for ecological research without the need for physical re-trapping. Whilst this is effective if animals pass within centimeters of tag readers, short-distance detection capabilities have prevented the use of this technology with many species. To address this problem, we optimized a large (15 m long) flexible antenna system to provide a c. 8 m2 vertical detection plane for detecting animals in flight. We installed antennas at two roosting caves, including the primary maternity cave, of the critically endangered southern bent-winged bat (Miniopterus orianae bassanii) in south-eastern Australia. Testing of these systems indicated PIT-tags could be detected up to 105 cm either side of the antenna plane. Over the course of a three-year study, we subcutaneously PIT-tagged 2,966 bats and logged over 1.4 million unique detections, with 97% of tagged bats detected at least once. The probability of encountering a tagged bat decreased with increasing environmental "noise" (unwanted signal) perceived by the system. During the study, we mitigated initial high noise levels by earthing both systems, which contributed to an increase in daily detection probability (based on the proportion of individuals known to be alive that were detected each day) from <0.2 (noise level ≥30%) to 0.7-0.8 (noise level 5%-15%). Conditional on a low (5%) noise level, model-based estimates of daily encounter probability were highest (>0.8) during peak breeding season when both female and male southern bent-winged bats congregate at the maternity cave. In this paper, we detail the methods employed and make methodological recommendations for future wildlife research using large antennas, including earthing systems as standard protocol and quantifying noise metrics as a covariate influencing the probability of detection in subsequent analyses. Our results demonstrate that large PIT antennas can be used successfully to detect small volant species, extending the scope of PIT technology and enabling a much broader range of wildlife species to be studied using this approach.

Cryptic diversity in Lithobateswarszewitschii (Amphibia, Anura, Ranidae)

Lithobateswarszewitschii is a species of ranid frog distributed from southern Honduras to Panama. This species suffered severe population declines at higher elevations (above 500 m a.s.l.) from the 1980s to early 1990s, but there is more recent evidence of recovery in parts of its range. Here we advocate for the status of Lithobateswarszewitschii as a candidate cryptic species complex based on sequence data from mitochondrial genes CO1 and 16S. Using concatenated phylogenies, nucleotide diversity (K2P-π), net between group mean distance (NBGMD) (πnet) and species delimitation methods, we further elucidate cryptic diversity within this species. All phylogenies display polyphyletic lineages within Costa Rica and Panama. At both loci, observed genetic polymorphism (K2P-π) is also high within and between geographic populations, surpassing proposed species threshold values for amphibians. Additionally, patterns of phylogeographic structure are complicated for this species, and do not appear to be explained by geographic barriers or isolation by distance. These preliminary findings suggest L.warszewitschii is a wide-ranging species complex. Therefore, we propose further research within its wider range, and recommend integrative taxonomic assessment is merited to assess species status.

Phenotypic and genetic diversity in aposematic Malagasy poison frogs (genus Mantella)

Intraspecific color variation has long fascinated evolutionary biologists. In species with bright warning coloration, phenotypic diversity is particularly compelling because many factors, including natural and sexual selection, contribute to intraspecific variation. To better understand the causes of dramatic phenotypic variation in Malagasy poison frogs, we quantified genetic structure and color and pattern variation across three closely related species, Mantella aurantiaca, Mantella crocea, and Mantella milotympanum. Although our restriction site-associated DNA (RAD) sequencing approach identified clear genetic clusters, they do not align with current species designations, which has important conservation implications for these imperiled frogs. Moreover, our results suggest that levels of intraspecific color variation within this group have been overestimated, while species diversity has been underestimated. Within major genetic clusters, we observed distinct patterns of variation including: populations that are phenotypically similar yet genetically distinct, populations where phenotypic and genetic breaks coincide, and populations that are genetically similar but have high levels of within-population phenotypic variation. We also detected admixture between two of the major genetic clusters. Our study suggests that several mechanisms-including hybridization, selection, and drift-are contributing to phenotypic diversity. Ultimately, our work underscores the need for a reevaluation of how polymorphic and polytypic populations and species are classified, especially in aposematic organisms.

Fungal infection has sublethal effects in a lowland subtropical amphibian population

BACKGROUND

The amphibian chytrid fungus, Batrachochytrium dendrobatidis (Bd), has been implicated as a primary cause of decline in many species around the globe. However, there are some species and populations that are known to become infected in the wild, yet declines have not been observed. Here we conducted a yearlong capture-mark-recapture study and a 2-year long disease monitoring study of northern cricket frogs, Acris crepitans, in the lowland subtropical forests of Louisiana.

RESULTS

We found little evidence for an impact of Bd infection on survival; however, Bd infection did appear to cause sublethal effects, including increased capture probability in the field.

CONCLUSIONS

Our study suggests that even in apparently stable populations, where Bd does not appear to cause mortality, there may be sublethal effects of infection that can impact a host population's dynamics and structure. Understanding and documenting such sublethal effects of infection on wild, seemingly stable populations is important, particularly for predicting future population declines.

Fragmentation alters home range and movements of the Dunes Sagebrush Lizard (Sceloporus arenicolus)

Habitat fragmentation is a major driver of biodiversity loss and among reptiles has been attributed as a cause of species decline. The negative effect of habitat fragmentation has also been shown to be worse for species that are habitat specialists. The Dunes Sagebrush Lizard (Sceloporus arenicolus Degenhardt and Jones, 1972) is a species that specializes on the shinnery oak (Quercus havardii Rydb.) sand-dune landform of the Mescalero–Monahans Sandhills ecosystem in western Texas and eastern New Mexico, USA. This landform has been fragmented by roads and well pads used for the extraction of oil and gas resources. The effects of fragmentation on the home range and movements of this species can lead to the effective isolation of populations and increased risk of localized extirpations. We showed that home-range size was larger in an unfragmented area and that the mean distance of movements was greater. We also observed that roads in the fragmented areas restricted movements of S. arenicolus. We concluded that roads can be barriers to movements even though only narrow strips of habitat are altered.

Comparison of personality between juveniles and adults in clonal gecko species

The developmental perspectives of animal personality enhance our understanding of how personality structure changes in relation to life stage. Clonal animals are ideal models for developmental studies because personality differences can be solely attributed to environmental factors. Here, I investigated the presence of personality within a species of clonal gecko, Lepidodactylus lugubris, at different developmental stages. For juveniles and adult geckos, I measured exploration (reaction to a novel situation) and boldness (risk-prone tendency) and evaluated repeatability and correlation of these behavioural traits. Each gecko exhibited different exploration and boldness with significant repeatability through time but no correlation between these behavioural traits. Small juveniles were composed of only bold and low explorative individuals but large juveniles and adults were composed of various personality type individuals. These results demonstrate that subject geckos have a similar personality structure across life stages and that exploration and boldness are independent personality without forming behavioural syndrome structure. Biased composition of personality type between life stages suggests that appearance of different personality type individuals during an early ontogenetic stage generates personality variation within the clonal population. This study provides developmental insight about personality structure and its composition in clonal animals living in the wild.

Survival and recruitment in the population ecology of the endangered Bombina pachypus (Amphibia: Anura)

Global amphibian decline is a subject of great conservation concern, yet often basic demographic information is absent, which prevents the understanding of population trends and the planning of effective conservation management. We analysed capture-mark-recapture data from six populations of the endangered Bombina pachypus in order to understand the relative contribution of survival and recruitment to population growth, and to assess if any differences exist among populations in terms of their population dynamics. We found that survival was rather high and generally constant among sites, and recruitment was low, with the exception of two single years at one site. Population growth depended on survival on all sites, except the years following high recruitment at one site. Annual population size was generally lower than 30 individuals, but in one site it was estimated to be larger than 50. Our findings suggest that juvenile survival is more important for population dynamics than recruitment from the larval to the juvenile stage. We also suggest that the low recruitment rates we recorded was a result of juvenile dispersal, and that when populations exhibited high recruitment it was due to occasional successful migration or local recruitment. This pattern could represent a way to counterbalance the risk of inbreeding in populations composed of few individuals, a common characteristic of populations of B. pachypus. Finally, we suggest that conservation measures for B. pachypus should be planned at the landscape scale, and should not be limited solely to the breeding site and its close surroundings.

ADVANCES IN ANIMAL WELFARE FOR FREE-LIVING ANIMALS

Over several decades, animal welfare has grown into its own free-standing field of scientific study, from its early beginnings in laboratory animal research to eventually include exhibited animals and farm animals. While it has always been present to some degree, consideration of animal welfare for free-ranging animals has lagged behind, developing as a field of study in the last 20 yr or so. Part of that increase was that animal welfare legislation was finally applied to studies being done on free-ranging animals. But it is the appreciation by the biologists and veterinarians working on wild animals, in which the quality of their results is largely controlled by the quality of the animals they use in their studies, which has resulted in increased attention to the well-being or welfare of the animals that they use. Other important influences driving the recognition of wildlife welfare have been changes in the public's expectations of how wild animals are dealt with, a shift in focus of wildlife professionals from managing animals that can be hunted or angled to include nongame species, the decrease in participation in hunting and fishing by members of the public, and the entry of large numbers of women into fish and wildlife agencies and departments and into veterinary medicine. Technical improvements have allowed the safe capture and handling of large or dangerous animals as immobilization drugs and equipment have been developed. The increasing use of sedating drugs allows for handling of animals with reduced stress and other impacts. A number of topics, such as toe-clipping, branding, defining which taxa can or cannot feel pain, catch-and-release fishing, and more, remain controversial within wildlife science. How we treat the wild animals that we deal with defines who we are as wildlife professionals, and animal welfare concerns and techniques for free-ranging animals will continue to develop and evolve.