Historically focused on training and enrichment, behavioral husbandry has become a standard fixture in zoos and aquariums. Enrichment planning has explicitly incorporated species' natural history since its inception. Despite this, many enrichment strategies have traditionally been developed by starting with items to be placed in animal habitats, with common practices of evaluating effectiveness centering on item-based checklists. In recent years, discussions among behavioral husbandry professionals have shifted toward a move from item-based to behavior-based strategies. Using this behavior-first approach relies on a broad view of the behavioral needs of animals. Focusing on the function and topography of behaviors may be useful for programs making this shift. Here we describe a behavior-first goal-setting process that considers function and topography, tools to aid the process, and examples of practical implementation. In addition to sparking different behavior-first ideas during the planning stage, this process can also provide a foundation for high-quality evaluation of the results of enrichment and other behavior-focused strategies.

Females generally prefer mates with traits indicating low stress (e.g., large size; good health). In captivity, stress from suboptimal housing might therefore reduce male attractiveness. We tested this hypothesis using mice (Mus musculus), predicting that compared to males conventionally housed (CH) in small lab cages, females will preferentially court higher welfare males from well-resourced (WR) 'enriched' conditions. First, a small-scale pilot opportunistically used 12 DBA/2 males and 22 DBA/2 females, both sexes differentially raised (half CH, half WR), but with heterogeneous reproductive experience. In T-maze mate choice tests, CH females preferred males from WR housing, spending significantly more time near and sniffing them. Next, the main study used 12 dyads of DBA/2 male litter-mates, differentially raised from 4 to 12 weeks old. Twelve virgin oestrous DBA/2 female sister pairs were each presented with two differentially raised virgin brothers. Ultrasonic recording confirmed courtship singing in all trials. Choice behaviour was videoed and analyzed blind to housing. Females spent on average 1.5 times longer near males from WR housing than their CH brothers, and sniffed them for nearly twice as long: significant preferences that did not vary with female housing. Effects were not explained by male body weight, testis weight or anogenital distance. Overall, as predicted, WR housing thus rendered males more attractive. When subsequently housed for mating in male-sister-pair trios, (6 WR and 6 CH), the WR trios also tended to be more likely to have litters. For species with problematic breeding programmes, improving welfare via higher-quality housing may therefore help improve reproductive success.

The success rate of deposited and harvested chelonian hatchlings between 2010 and 2023 were retrospectively reviewed by the North Carolina State University College of Veterinary Medicine Turtle Rescue Team. These data were analyzed to determine factors that may influence hatchling success including species, month of incubation, mother's status upon arrival, and the mother's presenting complaint. This study includes all wild chelonian species found in North Carolina that have presented as adult, gravid females over a 13-year period. These species include common snapping turtles (Chelydra serpentina), painted turtles (Chrysemys spp.), yellow-bellied sliders (Trachemys scripta scripta), cooters (Pseudemys spp.), eastern box turtles (Terrapene carolina carolina), eastern mud turtles (Kinosternon subrubrum), common musk turtles (Sternotherus odoratus), and red-eared sliders (Trachemys scripta elegans). Overall, there were a total of 2453 chelonian eggs and of those, 954 (38.9%) hatched. The greatest egg count numbers were recorded from common snapping turtles (703/2453, 28.7%), eggs collected in May (1300/2453, 53.0%), eggs that were collected from patients euthanized on arrival (1084/2453, 44.2%), and eggs that came from mothers presenting for vehicular trauma (1891/2453, 77.1%). Trauma did not significantly impact overall hatch rates, except for snapping turtles with vehicle-related injuries (p = 2.53e-08). Eastern Box Turtles had significantly lower hatch ratios (p = 0.000157), while aquatic turtles, such as musk and yellow-bellied sliders, fared better under current incubation protocols (p = 0.079 and p = 0.062, respectively). Results of this study represent opportunities to improve hatchling success and rearing under human care by understanding the major factors that contribute to their success.

Musth, a hormonally driven state characterized by increased testosterone, aggression, and physiological changes, poses significant management challenges for male Asian elephants (Elephas maximus) in zoos. Immunological castration, a nonsurgical method using anti-GnRH immunotherapeutic (Improvest®), offers a promising tool to suppress musth. This case study documents the behavioral and physiological effects of immunological castration in a 54-year-old male Asian elephant at the Oklahoma City Zoo with chronic musth-related welfare concerns. In June 2024, the elephant received a primary dose of Improvest® followed by four monthly boosters. Behavioral observations, animal care records, and fecal androgen metabolite (FAM) concentrations were monitored from January 2024 through the elephant's humane euthanasia due to unrelated degenerative joint disease in January 2025. Segmented regression analyses revealed that FAM concentrations and visible musth signs declined within 7 weeks of the first dose of Improvest®. Aggression also decreased significantly following an inflection point around this time. Even though changes in stereotypy, feeding, and recumbency were not statistically significant, some trended toward improved welfare. Notably, active spermatogenesis was observed at necropsy, suggesting that the effects of Improvest® may require longer to fully manifest or may be partially reversible. Although limited by its opportunistic, single-subject design and shortened study period, this case contributes valuable insight into the real-world application of immunological castration in geriatric zoo elephants. Immunological castration may serve as a useful strategy for male elephants with musth-associated health risks, especially those no longer intended for breeding. Continued longitudinal studies are needed to evaluate long-term efficacy, reversibility, and animal-specific responses to Improvest.

Ex-situ breeding programs often utilize pedigree-analysis to select breeding pairs with the goal of maximizing retention of genetic variation and establishing self-sustaining populations. These efforts are limited when selected pairs fail to reproduce successfully. Because mate-choice serves an important role in many mating systems, providing the opportunity to engage in this behavior could lead to greater pair compatibility and offspring survival. In this study, we investigated the impact of female mate-choice on reproductive success and animal welfare of two passerine species: blue-gray tanagers (Thraupis episcopus) and red-capped cardinals (Paroaria gularis). One group of females were allowed to demonstrate a preference between three potential males and were subsequently paired with their preferred mate. A second group of females were paired with their pedigree-assigned partner. We measured a variety of reproductive parameters (onset of nesting, number of eggs, and number of fledglings) and evaluated animal welfare using positive (behavioral diversity) and negative (fecal glucocorticoid metabolite) indicators of welfare. There was no statistically significant difference in reproductive success based on pairing method for either species. Females allowed to choose their mate had significantly higher behavioral diversity than those assigned a mate (p < 0.03), however there was no difference in male behavioral diversity between the two groups. These findings suggest that the opportunity for mate-choice may lead to greater welfare, but only for the individual expressing preference. Outcomes of the study highlight the many variables that can affect reproductive success and the considerable research still needed.

To manage ex situ breeding populations effectively, it is important to understand the factors that may lead to reproductive failure. In this study, we aim to understand factors associated with reproductive success in zoo-housed bush dogs (Speothos venaticus), and form evidence-based recommendations for their breeding management. We distributed a survey to global institutions housing bush dogs to collect data on factors which may affect litter survival. Responses were obtained from 30 zoos across 13 countries, providing data on 125 litter births between 2012 and 2022. Information from the Zoological Information Management System (ZIMS) and studbook records supplemented this dataset. We found that within northern temperate regions, the number of pups reared to the age of 1 month in bush dog litters (n = 112 litters) is linked to the ages of breeding individuals, prior breeding experience of females and birth season. The number of pups reared per litter declines with advancing maternal age, but this decline can be reduced by pairing with an older male; experienced females rear more pups per litter than inexperienced females, and litters born in the summer have better survival outcomes than other seasons. Sharing data between zoos provides greater statistical power to identify challenges associated with breeding lesser-researched species, allowing zoos to overcome these challenges through evidence-based management changes.

Polar bear (Ursus maritimus) neonates are highly altricial, and in-den maternal care is required for cub survival and as follows, population health. Study of maternal denning polar bears in managed care can provide valuable insights on mother-cub dynamics. We reviewed video recordings of polar bears in maternal dens from three participating zoos to monitor maternal behavior and cub development. The study subjects included three polar bear mothers with a single cub. During a total of 366 observations, we collected behavioral data on both mother and cub during 30-min observation sessions spaced every 4 h for the first 30 days post-partum. We recorded mother-cub contact and individual behaviors for both the mother and cub. During the first ten days postpartum, cubs spent 60% of the time on their mother, usually in a cradled position, and this behavior decreased to 44% thereafter. Mothers and cubs spent most of the time resting, with mothers occasionally licking and attending to their cubs. Cubs spent approximately 12% of the time nursing. More replicates from ex situ populations will refine our understanding of how the denning environment, maternal care behavior and cub development are correlated with cub survival.

Research on positive animal welfare has prompted exploration and implementation of methods to stimulate the behavioral repertoires of zoo-housed species. We investigated the impact of a modified feeding method on the behavioral diversity, activity budgets, and social relations of five African lions at Zoo Antwerpen. The original method involved daily individual feedings indoors while the modified method provided group feedings three times a week outdoors. Observations spanned 6 weeks (3 weeks per method and a 1-week habituation period in between), yielding 150 h of behavioral data using continuous focal sampling. Results indicated a significant increase in behavioral diversity with the modified method across all observed time (p < 0.001). This was accompanied by an increase in active (for females, p < 0.001) and exploratory behaviors (p < 0.001). Time spent feeding did not change significantly. Inactivity levels shifted (p < 0.001), aligning more closely with natural wild lion behavior patterns. In the modified method, lions spent more time feeding and exploring on feeding days compared to fasting days (p < 0.001 and p = 0.009). Inactivity was lower on feeding days (p = 0.001), while overall activity levels did not change significantly. Social network analyses showed no significant changes in agonistic or affiliative behaviors, indicating the feeding method change had limited effects on social relations. In conclusion, our study underscores the importance of feeding methods in promoting natural behaviors and enhancing welfare outcomes for zoo-housed African lions, emphasizing the need for tailored management strategies to support natural behaviors and welfare.

Zoos are interested in assessing the well-being of the animals in their care, including potential impacts from environmental and anthropogenic factors which could alter welfare. Zoos also provide a unique environment whereby visitors can get within proximity to wild animals, which can have positive, neutral, or negative impact for the exhibited animal's welfare. Within zoo settings, there has been little research published on these welfare impacts for reptiles, specifically snakes. Additionally, there is limited knowledge on their behavior in relation to captive welfare. Three snakes were selected, and conditions were implemented outside of their habitats to alter visitor proximity. The three conditions experimentally altered the proximity of people near the snake habitats and included Visitor-Natural (regular visitor proximity), Visitor-Control (no visitors within a 210 cm radius), and Visitor-Experimenter (an experimenter within close proximity throughout the observation time). An ethogram was developed and measured across a within-subject reversal design for all three conditions. Results indicated that overall, there was a neutral to positive impact of the Visitor-Natural condition. However, the highest negative impacts were observed during the Visitor-Experimenter condition, including increased abnormal behaviors. This study suggests that snakes will habituate to people but may be affected by short-term, unpredictable behavior from visitors. The results are discussed in terms of visitor impacts on exhibited snakes, as well as implications for assessing overall snake welfare.

ABSTRACTSinging is an ecologically important behaviour for songbirds. Syllables function as the building blocks of birdsong, so changes to their production will have implications for overall song structure. It is well established that anthropogenic disturbance can influence syllable production in wild songbird populations, but the effect of anthropogenic disturbance on syllable production in ex situ populations has not been studied. We set out to fill this gap by comparing the syllable production of Chester Zoo's Bali myna (Leucopsar rothschildi) population during a period of zoo closure in 2020 (due to the COVID‐19 lockdown) to a period of normal zoo opening in 2019. The number of syllables per song, the rate at which syllables were produced and the diversity of syllables all showed evidence of plasticity across days and years. However, only the number of syllables per song responded significantly to anthropogenic disturbance. Changes in syllable number due to anthropogenic disturbance could mitigate potential signal masking from unpredictable noise, although communication efficacy may still be affected. As a result, changes in vocal communication could impact conservation breeding programmes by altering the way that individuals interact with conspecifics.