Touch tanks are a feature in a number of zoos and aquariums, but the usage of these interactionbased exhibits may create concerns for animal welfare. It is unclear whether or not touch tanks have a negative impact on shark and ray wellbeing. The purpose of this study is to examine the behaviour of animals based on crowd size in the Shark and Ray Bay touch pool exhibit at the Aquarium of Niagara. Data were collected from November 2022 until January 2024 via the exhibit's security camera to observe exhibit use by whitespotted bamboo sharks Chiloscyllium plagiosum, Atlantic stingrays Hypanus sabinus and yellow stingrays Urobatis jamaicensis. We collected data for 5 minutes per hour throughout the Aquarium's open hours multiple times per week. All three species spent significantly less time on the ledge, where visitors could touch them, when crowd sizes were high. The results were particularly strong for both ray species. These patterns should be taken into consideration when structuring touch tank activities to enhance welfare of the animals involved. We provide suggestions for zoological facilities that still house animals in touch pools to ensure that their welfare needs are being achieved to the highest standard.
The eastern massasauga Sistrurus catenatus is an at-risk pygmy rattlesnake species experiencing decreasing populations in the wild. These declines have led to the establishment of ex situ conservation programs in accredited zoos. Information related to body size and growth are critical for the success of ex situ conservation programs, but there is a lack of physiological research into zoo-housed massasauga populations. This study aimed to: 1) determine average body mass and growth rate across growth windows, and 2) determine which factors (sex, institution, origin) influence the size and growth of eastern massasaugas in zoos. A total of 76 females and 94 males (N=170) born between 2000-2021 across 18 institutions were analysed from the Species360 Zoological Information Management System (ZIMS). Results indicated that average body mass was not different between the sexes in any of the growth windows. The average mass of neonates at birth was not different between females and males. The growth rate was highest during the 12-35 month period of life, where females experienced a higher growth rate than males. Institution significantly affected both mass and growth rate. The origin of snakes (wild vs. zoo) affected birth mass and early growth rate, but not overall body mass in any window. Comparison to the literature indicated zoo-housed adult eastern massasaugas are heavier than wild individuals. These findings reveal important allometric information about the eastern massasauga rattlesnake that can inform zoo husbandry practices to improve animal health and wellbeing, and contribute to breeding success.
Black rhinoceros Diceros bicornis is considered solitary in the wild, but the Hiroshima City Asa Zoological Park, Japan, has housed a family group with good reproductive outcomes over five decades. Together as a group during the daytime, the members are separated at night. During quantitative observations on this group over more than 4 years, focusing on maternal behaviours and social relationships among individuals, we recorded two unexpected behaviours previously reported in some mammal species that live in well-organized social groups such as primates and elephants, but not in black rhinoceros nor, to our knowledge, any other ungulates: 1) A mother sometimes allowed her two older offspring to suckle repeatedly after she again gave birth, but she accepted their suckling attempts less frequently and terminated their suckling bouts more frequently than those of her new calf, suggesting at least partial satisfaction of unusual suckling demands of older offspring, and differential responding to suckling demands by offspring of different ages. 2) Directly following an unfulfilled suckling demand, one older offspring sometimes displayed aggression toward their younger siblings, similar to redirected aggression seen in animals living in social groups when the victim of a conflict then threatens or attacks a third party. These findings show that black rhinoceros living in a family group in captivity can maintain stable dominance relations, with behavioural tolerance and sociality sufficient for coping with various demands and agonistic situations.
Understanding the mechanical forces acting on the beak is crucial to enhancing the management of maxillary beak avulsion cases. Therefore, this study aimed to biomechanically evaluate the upper beaks of five Neotropical bird species and analyze Hounsfield units (HU) values using computed tomography (CT). Analysis was performed on white-eyed parakeet Psittacara leucophthalmus, red-legged seriema Cariama cristata, black-headed vulture Coragyps atratus, buff-necked ibis Theristicus caudatus, and toco toucan Ramphastos toco. A mechanical bending test was performed with a load applied perpendicularly to the distal third of the maxillary rostrum in the ventrodorsal direction. HU values were determined at three points of interest in the same area where the actuator was applied. There were no statistical differences in the HU values between parakeet and seriema beaks, while all other bird species exhibited statistical differences. The maximum force was highest for the parakeet (682.2 N) and toco toucan (126.6 N) beaks, followed by the seriema (65.3 N) and black-headed vulture (57.6 N), with the buff-necked ibis having the lowest force (21.2 N). Statistical analysis revealed differences in maximum force between the parakeet's beak and those of all other species. Significant differences occurred in maximum deformation between the black-headed vulture and buff-necked ibis beaks, and between the seriema and buff-necked ibis beaks. Statistical differences were also observed in the moment of the toco toucan's beak compared to the other bird's beaks. In conclusion, the data obtained may support future studies on prosthetic materials for the species analysed, taking into account the differences identified through the mechanical test.
In the spring of 2023, a zebra Equus grevyi at Kolm & aring;rden Zoo was euthanized due to colic. During the autopsy, over 20 kg of sand was found in her intestines. During the summer of 2023, it was noted that the black stripes of the rest of the zebra group appeared less dark than usual. Two mares were observed actively eating sand at a specific location for the first time in August; when moved, they were not seen eating sand in other enclosures. When moved back to the original enclosure, they returned to eating sand from the same spot. Analysis of the sand from that specific location, compared to sand from other areas in the enclosure, showed markedly higher levels of copper (Cu), a mineral suggested to be associated with geophagia in horses Equus caballus when deficient. This, together with the coat coloring, strengthened suspicions of a Cu deficiency. The total diet had previously contained 9 ppm Cu in dry matter. First, the pellet feed was increased to raise this to 12 ppm; then, the pellet recipe was adjusted so that the diet increased to 14 ppm without further increasing the pellet amount. 30% of the Cu sulfate was replaced with copper chelate to putatively enhance absorption. In the spring of 2024, the amount of pellets was reduced while a Cu and zink chelate supplement was added, so that the total diet contained about 15 ppm Cu, with most of the Cu coming from bioavailable sources. During the summer of 2024, the zebras were not seen eating sand, except for one occasion after the introduction of a new stallion, during which the mares exercised intensively for many days. The results suggests Cu as the underlying cause of the observed behavior, which in turn may indicate nutritional wisdom.
Stereotypic behaviours may be heterogenous in nature for some species and thus have different causes or motivations. The current study examined stereotypic behaviour in two polar bears Ursus maritimus, one male and one female, at Brookfield Zoo Chicago. Data were collected at four different times throughout an approximate one-year period. Results suggest that stereotypic behaviour in polar bears may be heterogenous in nature as has been documented in other species. Pacing behaviour typically occurred in locations best suited to watch for the presence of animal care staff. However, the main location the male engaged in route tracing was near a window where the female could be visually observed but not physically interacted with during the spring which is the breeding season. In addition, principal components analysis reveals pacing and route tracing do not co-occur providing additional support that stereotypic behaviours in polar bears may be heterogenous in nature. Only through research and understanding the motivations for these behaviours will zoos be able to have a positive impact on the animals' welfare. Information gained from this study can assist future studies in ensuring stereotypic behaviours are scored separately during behavioural data collection.
The cotton-top tamarin Oedipomidas oedipus is currently classified as critically endangered by the IUCN, prompting intensive conservation efforts, including the maintenance of healthy populations under human care. However, ensuring optimal welfare and health remains challenging, particularly in terms of nutritional management, due to inherent issues observed in callitrichid species in captivity. This study aimed to evaluate fecal consistency in cotton-top tamarins and investigate its association with different dietary regimes. A survey was conducted across 10 zoological institutions, encompassing 69 individuals, to collect data on dietary practices and faecal consistency. Faecal evaluation was assessed using a scale from 1 (solid) to 6 (watery), based on appearance and texture. A comparative analysis of institutional diets was performed based on the proportions of food groups offered, including cultivated fruits, vegetables, commercial foods, animal protein, supplements, and exudates. These proportions were then analysed in relation to faecal scores. In addition, individual body weights were evaluated in relation to the amount of food provided at each institution. A positive correlation was found between fruit inclusion levels and higher faecal score. Variations in body weight were observed among institutions, with lower average weights recorded in females where food quantities were reduced. A standardized faecal scoring system was developed to support health monitoring and animal management protocols.
Common octopus Octopus vulgaris are a popular exhibit in aquaria; however, there is limited research on the nutritional requirements of this species. The current information available is from the aquaculture industry and thus focused on young individuals and maximising growth rates. Diets for 17 common octopus housed in aquaria in Europe were collected and ingredients identified. Nutritional analyses of these items were undertaken, including protein, fat, energy and a range of minerals to produce profiles of each animal's weekly diet. All but one collection fed a mixture of fish and marine invertebrates with shore crabs being the most provided item followed by molluscs (mussels and clams), mimicking the natural diet. Octopus were fed between 3 and 7 times per week. All of the diets had protein levels above 50 % (in dry matter, DM) and many of the diets (59 %) had protein levels of over 60 % DM, which is expected as protein is the main macronutrient for octopus. Fat levels were variable between collections with most diets being higher in fats than recommended. This study highlights the variation in diets provided to common octopus. Further research on the impact of these diets on growth, development and longevity would be beneficial in developing recommendations for octopus diets.
Two-toed sloths Choloepus spp. are poorly studied folivores and currently lackspecies-specific research on the nutritional composition of their diet in the wild. Some studies have been published on zoo diets; however, direct comparison between collections is not common in the literature. A nutritional assessment was performed on nine zoo diets of Choloepus didactylus from eight zoological collections across the United Kingdom and Ireland. Diets were compared against one another to test if there were significant differences in the nutrient content between collections. Analysis focused on average dietary provision per sloth for the following nutrients: crude protein (CP), crude fibre (CF), Neutral detergent fibre (NDF), Acid detergent fibre (ADF), calcium (Ca), phosphorous (P) and nitrogen-free extract (NFE), which is an estimate of the easily digestible carbohydrates. ZootritionTMwas used to determine the nutritional content of each diet. Results showed there were variations in the quantity of food provided per sloth as well as differences in the nutritional composition of diets between collections. Browse is recommended for this species; however, only five out of nine diets (56%) included browse. Compared to recent recommendations, all diets exceeded the minimum protein content recommended; however, fibre contents were lower than recommended. This may be due to limited browse and leafy vegetable provision in some of the diets. Browse is recommended for this species because it improves digestive health, increases overall NDF levels in the diets and reduces the NFE content. Conclusions drawn from this study highlight the importance of further nutritional research and consideration of published guidelines to improve the health and welfare of C. didactylus in zoos.
White Ceratotherium simum and black Diceros bicornis rhinoceroses differ in ecology and sociality, which is reflected in their ease of care in zoos. Zoo-housed black rhinos are susceptible to unusual diseases, like iron overload disorder and hypophosphatemia, that have hypothetically been linked to obesity. We applied published body condition scores (BCS; 1-5) to 84 adult white and 57 adult black rhinos living in 41 European zoos, established our own BCS protocol with overview scores and scores for individual body regions, based on our ability to distinguish scores on photographs, and related these to husbandry conditions. Exact body mass was available for 17 and 20 white and black rhinos, and was estimated for the rest. Scoring was conducted by one single observer, twice in a blinded manner. White rhinos were kept in larger enclosures and received a lower proportion of non-forage feeds than black rhinos. Contrary to previously published BCS protocols, the protocol presented here achieved a distinctively higher number of identical scores at repeated scoring from photographs for all evaluated body regions. BCS were generally positively correlated to body mass, but were not related to the percentage of non-forage feed in the individual diets. White rhinos had higher scores than black rhinos (e.g., BCS overview side 3.83 +/- 0.76 vs. 3.39 +/- 0.85), suggesting that obesity, if at all, is more common in white rhinos. Additionally, BCS were relatively independent of age in white rhinos but declined in black rhinos with age, supporting concepts of chronic, accumulating health problems in black rhinos. In black rhinos, BCS were lower in animals with impaired dental status compared to animals without such alterations. In both species, males tended towards lower BCS compared to females. BCS had no effect on female black rhinos breeding status, but tentative evidence suggested that non-breeding white rhinos show higher BCS. Our findings do not support concepts that associate black rhino health problems with obesity, but emphasize the relevance of strategies for maintaining long-term health. In white rhinos, the provision of ad libitum forage is considered beneficial from a behavioural point of view, but forages of sufficiently low nutritional (but appropriate) quality should be chosen to prevent overconditioning.
Feeding practices are critical for the welfare of zoo-housed carnivores, yet zoo diets often lack the complexity of natural prey, potentially reducing stimulation and increasing stereotypic behaviours. This study examined how different food items combined with a fasting regime influenced the behaviour and activity budgets of three jaguars Panthera onca over eight weeks. Four feeding treatments were tested: featherless chicken, feathered chicken, beef meat without skin on bone (all with three feeding, four fasting days per week), and whole sheep or goat carcasses (two feeding, five fasting days per week). Behaviours were recorded continuously based on an ethogram, and beta regression mixedeffects models were used for analysis. Whole carcasses elicited the longest feeding times (88 +/- 21 minutes), compared to meat on bone (58 +/- 23 minutes) and chicken (32 +/- 10 minutes feathered, 12 +/- 4 minutes featherless) on feeding days. Large carcasses also encouraged unique behaviours such as food carrying, guarding, and manipulation, while providing intermittent feeding opportunities and possibly prolonged satiation. Although these differences were evident in feeding-related behaviours, overall activity budgets remained largely stable, and stereotypic pacing was not substantially affected by diet composition or fasting schedules. These findings underscore the enrichment potential of whole carcasses in promoting natural behaviours and enhancing feeding engagement. Zoos may benefit from incorporating more varied and naturalistic feeding regimes to improve animal welfare.
"Enrichment" in its simplest definition, is the positive enhancement of an animal's mental and physical needs, making it a critical component of optimal animal care practices. Animals at the Cape May County Zoo are provided environmental enrichment as part of their daily husbandry. In addition to other forms of enrichment, zookeepers provide a variety of environmental enrichment devices (EEDs) in order to attain behavioral goals. For the callitrichid species housed at the zoo, zookeepers offer a wide range of EEDs commonly used at other zoological facilities, including 'toys' often designed for parrots, wild birds, exotic pets, and human toddlers/infants, with the goal in stimulating natural behaviors including foraging, exploration, and play. Zookeepers also provide social enrichment by entering the enclosure with the callitrichids for handfeeding and training. The goal of this study was to determine if the "type" of enrichment provided (i.e. regular toys, human toddler/infant toys, etc.) to the callitrichids or if signage about primates as pets appeared to influence whether zoo guests expressed that they would be suitable/desired pets. A troop of five-related cotton-top tamarins Saguinus oedipus were chosen as the focal subjects for this study and data were collected from zoo guests on their perceptions of pet suitability for each enrichment type. In the next stage, data were again collected from guests when a sign with information on 'why primates make unsuitable/undesirable pets' was placed in front of the habitat in lieu of EEDs to investigate the presence of that sign on guest perceptions. Analyses of these data underscored a significant association between enrichment condition and guest perceptions of tamarins as good pets, but results of differences in guest perceptions based on the enrichment condition present were less conclusive. This study nonetheless holds significant value as a pioneering effort in investigating public perceptions about nonhuman primate species (NHPs) in a zoo setting and whether the way they are presented to the public influences their suitability/desirability as domestic pets.
The Sumatran laughingthrush Garrulax bicolor is an endangered passerine endemic to Sumatra. To combat further population decline, a European Association of Zoos and Aquaria European Endangered Species Breeding Programme was established in 2011. The aim of this review was to investigate the causes of death of Sumatran laughingthrushes in captivity, allowing the development of preventative methods to reduce mortality, improve breeding rates and the long-term viability of the captive population. The deaths of 310 Sumatran laughingthrushes were reviewed from institutions participating in the breeding programme between 2005-2021. Infectious diseases were the most common causes of death, with aspergillosis the most prevalent infectious aetiology. Aspergillosis was significantly more likely in parent reared birds (P=0.027) and the juvenile age class (P=0.028), but significantly less likely in the Indonesian institution C (P= 0.043). Trauma was the second most common cause of death, and intraspecific aggression the most prevalent traumatic aetiology for both adults and juveniles. Few conclusions could be drawn from the neonatal data due to lack of necropsy information. Systemic Isospora spp. infection was a rare cause of death, but there was insufficient data to assess its subclinical prevalence. Institutions should attempt to perform more necropsy procedures for all age classes and screen all deceased birds for systemic Isospora spp. infection. This review achieved its aim of investigating the causes of death in captive SLTs and suggested routes for further research.
Spatial data with explicit geographic coordinates has seen limited application in zoo biology, with collection and analysis methods developing more slowly than other methodologies. With the increasing availability of technologies that streamline these processes, spatial data can now be more efficiently integrated into standard zoo practices. This article presents a method for translating data from ZooMonitor into QGIS for spatial analysis. The approach was applied to data from four species housed in multi-species enclosures across two Irish zoological institutions. The resulting GIScompatible data were used to explore the potential benefits of spatial analysis in enhancing captive animal welfare. Analyses included both traditional and novel (for ex-situ settings) spatial metrics: Modified Spread of Participation Index (mSPI), Minimum Bounding Convex Hulls, Mean Coordinates, Standard Distances, Standard Deviational Ellipses, and Kernel Density Estimators. While mSPI remains a valuable tool, its limitations when used in isolation are demonstrated. The advantages of combining multiple spatial measures are highlighted. Among the metrics examined, Standard Distance, Minimum Bounding Convex Hull, and mSPI were useful for understanding overall range. For finer-scale insights, Standard Deviational Ellipses and Kernel Density Estimators provided clearer interpretations of space use, better suited for informing husbandry and management decisions. Using multiple methods in tandem allows researchers to support more informed decisions regarding enclosure design and animal care. This study illustrates how spatial approaches, rarely applied in captive settings but increasingly feasible through tools like ZooMonitor, can offer new insights into animal welfare and management. The findings emphasize the importance of using a suite of spatial metrics rather than relying on a single method, which may introduce bias or limit interpretation. In conclusion, this article demonstrates the potential of GIS-based analyses to support zoological institutions in improving enclosure infrastructure and prioritizing animal welfare, particularly for critically endangered species.
Ageing chimpanzees Pan troglodytes in zoological settings often experience physiological decline, including loss of body condition and muscle mass, which can negatively impact welfare and longevity. Over a three-year period, three elderly chimpanzees at Antwerp Zoo exhibited rapid and unexplained deterioration in body condition, whereas other group members remained in good health. Despite comprehensive diagnostic evaluations, including blood analyses and cardiac assessments, no underlying medical cause was identified. Given the importance of maintaining social bonds in older chimpanzees, individual intervention was implemented without disrupting group structure or routines. A high-protein, energy-dense, lactose-free shake was formulated to provide supportive nutrition, incorporating whey protein, rice milk, both soluble and insoluble fiber, and omega-3-rich fats, delivering approximately 1837 kJ ME per portion. The shake was administered individually as part of an established routine involving indoor herbal tea distribution, minimizing disruption and competitive behaviours. All three individuals showed marked improvement in body condition scores (from 2.0-2.5/10 to 3.8-4.2/10) over several months, alongside improved coat quality and increased alertness or activity. The intervention proved feasible, non-invasive, and socially compatible, offering a promising approach to geriatric care in great apes. However, long-term effects of sustained protein-rich supplementation remain unknown. Further research is needed to evaluate its impact on overall dietary intake and to determine its applicability across other great ape species.
Studbooks are an important tool used in zoos and aquaria globally as a means of managing important animal populations. While the primary goal of a studbook is to manage genetic diversity, these programmes also have great value in collating information on breeding and husbandry practices across multiple international facilities. The aim of this study was to investigate possible triggers for breeding, enclosure design, husbandry styles, and challenges in the keeping of three amazon species in European Association of Zoos and Aquaria (EAZA)-approved holders. A breeding and husbandry survey was distributed, courtesy of the EAZA Ex situ Programmes (EEP), to holders of the Ecuadorian Amazona lilacina, red-tailed Amazona brasiliensis and red-crowned amazon Amazona viridigenalis in 2024. A total of 23 holders responded to the survey, reporting on the husbandry of 54 amazons. Ten holders (43.48%) had successfully bred these species in the past. The challenges outlined by respondents included individuals too young or too old for breeding, aggression from birds directed at keepers, and hesitancy to breed animals due to challenges with sourcing zoos to take the offspring. The majority of holders (22/23, 95.65%) provide regular enrichment, with nutritional enrichment being the most common form, while cognitive (15/23, 65.22%) and social enrichment (4/23, 17.39%) was used less frequently. These parrots are sometimes kept alongside other species such as small birds and primates. It is hoped that the results of this survey may improve the understanding of the husbandry criteria for amazons, and may aid in developing breeding protocols in the future.
Understanding how zoo animals use their enclosures is essential for welfare-oriented management. This study demonstrates how digital tools like the Zoo-Observer app can enhance spatial behaviour monitoring by enabling the collection of fine-scale positional data, including home range estimates and walking distances. We applied this approach to Rothschild's giraffes Giraffa camelopardalis rothschildi, Grant's zebras Equus quagga boehmi, and blue wildebeests Connochaetes taurinus taurinus housed in a mixed-species savannah exhibit at Opel-Zoo, Germany. Data were collected over two consecutive years, enabling a unique comparison to be made of the behaviour of the same social groups before and after the birth of juveniles. The temporary relocation of hay feeding sites was used as a loweffort intervention to test behavioural flexibility. While zebras adjusted their enclosure use, giraffes and wildebeests remained spatially stable, reflecting their species-specific foraging strategies and social dynamics. Our findings demonstrate that combining behavioural observations with spatial metrics, such as covered distance, provides a more comprehensive understanding of enclosure use and activity patterns. This approach informs evidence-based, species-specific husbandry decisions and demonstrates the potential of app-based tools for monitoring.
Artificial heating via lamp technology is a key feature of the husbandry of many captive animals, especially ectotherms. Short wave infrared (IRA) is theoretically more efficient in raising animal core temperature than medium (IRB) and long wave infrared (IRC) as it penetrates deeper into the skin and underlying tissues. However, for historical reasons, lamps emitting predominantly long wave infrared are commonly used, causing superficial heating and dehydration in animals due to shallow tissue penetration and more uneven heating of surface versus core. Few studies have investigated real-world behavioural or physical responses to different infrared wavelengths; therefore, there is a lack of empirical evidence for physiological outcomes under controlled conditions. Here, we investigated the effect of different infrared basking lamps (infrared A, B and C lamps available commercially) on time to reach core target temperature, surface heating, and desiccation rate of ballistic gelatine models in order to link theory to practice. Accounting for variation in air temperature and humidity, infrared A lamps heated models to core target temperature fastest, and demonstrated the lowest desiccating effect, while infrared C lamps caused the highest surface heating. Lamp to model distance influenced time to reach target temperature, while background colour influenced surface temperature changes. Our results provide support that, among commercially available products, lamps emitting infrared A radiation heat the core of animals in captivity more efficiently, with less desiccation and thus confirms the theoretical assertion that such lamps are preferable for use in animal husbandry. This study also develops methods for future infrared heating research.
Zoo animal welfare assessments can be applied to multi-species risk evaluations to species-specific, animal-based protocols. The latter are more difficult to develop and implement due to time-intensive data collection and difficulties with standardisation. The Cetacean Welfare Assessment (C-Well) was published a decade ago and has been applied globally more than 30 times across five cetacean species, with many facilities conducting repeated assessments, and has undergone multiple updates to align with the latest research. This paper reviews the C-Well's application over the past decade, highlights key insights from the collected data, and details the measure composition in the C-Well version 2.0. The effectiveness, limitations and future directions of the project are explored in detail, including how its scope can be broadened. The C-Well's evolution has recently been leveraged to develop the Zoo-Well approach which uses a core framework designed to allow species-specific welfare assessments to be readily developed, and which has been conducted successfully on a dozen species to date.
Ambystoma dumerilii is a Critically Endangered amphibian endemic to a single lake in Mexico. The species is the focus of conservation efforts which include individuals maintained in captivity for captive breeding. To manage captive colonies effectively, and to monitor the wild population, a means of individual identification is required. This study marked N=80 captive individuals subcutaneously with a passive integrated transponder (PIT) tag to monitor the rate of retention. Body weight and behavioural observations were used to monitor the impact on the individual. Tag retention was 97.5 % across the population with no observable health impacts noted.
