Zoo Elephant Research Articles

BITS: A Bayesian Isotope Turnover and Sampling model for strontium isotopes in proboscideans and its potential utility in movement ecology

Abstract Strontium isotope ratios (87Sr/86Sr) of incrementally grown tissues have been widely used to study movement ecology and migration of animals. However, the time scale of 87Sr/86Sr incorporation from the environment into tissue and how it may influence data interpretation are still poorly understood. Using the relocation of a zoo elephant (Loxodonta africana) named Misha, we characterise and model the 87Sr/86Sr turnover process using high‐resolution measurements of its tusk dentine. We seek to develop a framework that can improve quantitative interpretation of 87Sr/86Sr data in tissues. The 87Sr/86Sr transition associated with the relocation is measured using laser ablation inductively coupled plasma mass spectrometry (LA‐ICP‐MS) on a prepared tusk slab. We develop a turnover model (BITS), with a rapidly exchanging central pool and a slowly exchanging peripheral pool, in a Bayesian statistical framework. The measured dentine data are first used to calibrate model parameters. The parameters are then used to estimate possible 87Sr/86Sr input time series from two datasets via model inversion: a fidelity test using Misha's dentine data and a case study using published dentine measurements from an Alaskan Woolly Mammoth (Mammuthus primigenius). The LA‐ICP‐MS data are consistent with a two‐compartment turnover process with equivalent half‐lives of 41 days for the central pool and 170 days for the peripheral pool. The model inversion shows good fidelity when estimating the intake 87Sr/86Sr time series associated with Misha's relocation. In the case study, the model suggests an abrupt pattern of change in, and a much wider range of, intake 87Sr/86Sr values than expressed in the woolly mammoth dentine data themselves. Our framework bridges the gap between environmental 87Sr/86Sr variation and data measured in tusk dentine or other incrementally grown tissues. It could be coupled with movement models and additional isotope tracers to study seasonal residency or the spatial and temporal patterns of movement/migration. The generic turnover processes can be adapted to other isotope systems, additional incremental tissues, or other organisms, thus expanding our modelling toolkit to investigate niche partitioning, life history traits and behavioural patterns in conservation biology, archaeology and paleoecology.

Social Dynamics of a Newly Integrated Bachelor Group of Asian Elephants (Elephas maximus): Welfare implications

ABSTRACT Male associations are a typical component of elephant society, allowing bulls to practice appropriate social behavior. To improve zoo elephant welfare, it is important to provide bulls with social opportunities. In fall 2018, Denver Zoo added two bull Asian elephants to its existing all-male group of three bulls, offering the opportunity to conduct a systematic behavioral study of the integration of the new bulls into the resident group. We recorded aggressive and affiliative behaviors before, during, and after the introduction of the new males. The proportion of aggressive behavior was significantly higher during the five-month introduction period compared to before their introduction. By the end of the study period, the elephants engaged in significantly more affiliative behavior and less aggressive behavior than during the introduction period, suggesting they had formed a new stable social dynamic. These results suggest group compatibility and positive elephant welfare resulting from housing male elephants together and can be used to inform management plans for bull elephants that prioritize their welfare.

Increasing browse and social complexity can improve zoo elephant welfare.

While recent work has assessed how environmental and managerial changes influence elephant welfare across multiple zoos, few studies have addressed the effects of management changes within a single institution. In this paper, we examine how management changes related to social structure and diet affect the behavior of a group of zoo elephants over a 23-month period while also considering underlying factors, such as time of day, hormonal cycle, and individual differences. We recorded individual behaviors using 2-min scan samples during 60-min sessions. We analyzed behavioral changes across several study variables using generalized linear mixed models. We found that increasing browse can improve opportunities for foraging throughout the day but may not be sufficient to reduce repetitive behaviors. We observed that increasing group size and integration of bulls with cows can lead to increased social interaction in African elephants. Our results highlight the importance of using multiple management alterations to address elephant welfare, and considering environmental factors, when making management decisions.

Forward and inverse methods for extracting climate and diet information from stable isotope profiles in proboscidean molars

Intratooth stable isotope profiles in enamel provide time series of dietary and environmental information that if correctly interpreted, serve as archives of seasonal variability in past environments. A major challenge in interpreting these profiles arises from time averaging imparted by enamel mineralization and developmental geometry, whereby the primary (δ13C or δ18O) input signal is attenuated and shifted, which can potentially lead to incorrect interpretations of the magnitude or frequency of seasonal variability. Several forward and inverse models have been developed to reconstruct the primary input signal from intratooth profiles in continuously growing teeth. Here the models developed by Passey and Cerling (2002) and Passey et al. (2005) are extended to molars of Elephantinae, which grow over a long but finite interval of time. Proboscidean molars are particularly attractive for intratooth profiles because they may contain a decade or more of information and they are often well preserved in the fossil record because of their thick enamel and large size.Forward model parameters are established using histological analysis of molar thin sections of extant African elephants (Loxodonta africana) and a mammoth (Mammuthus columbi) and by micro-CT analysis of L. africana molar plates. The density of immature enamel is about 65% of the final density of mature enamel. The appositional length varies from approximately 35 to 55 mm, and the maturation length is about 70 mm. Histological methods are used to determine crown formation time (CFT) in elephant and mammoth molar plates. CFT for the elephant and mammoth molar plates studied in thin section are about 5–6 years and 11 years, which translate to mean growth rates of about 21 mm/year and 16 mm/year, respectively.Coeval molar and tusk profiles from a zoo elephant are compared. The tusk isotope profile serves as a proxy for the primary input signal, and thus provides an opportunity to evaluate the forward and inverse models. The results from the zoo elephant profiles demonstrate that the inverse model accurately reconstructs the amplitude and overall structure of the primary input signal. Inverse model results of mammoth molar profiles show double the range of δ13C in measured enamel profiles. Inversion model results illustrate that improved reconstruction of the primary input signal can lead to more accurate interpretations of the seasonal variability of diet and body water and by extension, vegetation and precipitation in past environments.

Social Interactions in Zoo-Housed Elephants: Factors Affecting Social Relationships.

Simple SummaryIn the wild, elephants live in large, complex social groups. Herds consist of a mixed structure of related females and their calves. One area of concern regarding the maintenance of zoo elephants has been the inability to provide them with social groupings that reflect wild group structure, and whether this impacts on their welfare. Here, we investigated whether a number of factors at the individual (e.g., personality, age or relatedness to others) and zoo (e.g., herd size, presence of calves in the group) level affected the frequency of social interactions in zoo elephant herds. Interactions were defined as positive or negative and then subdivided into physical and non-physical interactions. Social interactions were found to be related to age, personality, presence of calves in the herd, relatedness to other elephants in the herd and species (African or Asian). Calves engaged in the greatest amount of positive interactions but no extreme aggression was observed between any individuals, which was considered indicative of good social management. Increasing understanding about social structures that are affecting elephant relationships enables targeted management plans to be created, in order to provide elephants with the most appropriate social environments. These findings support the recommendations that elephants should be housed in related herds with multiple ages wherever possible, but they also highlight that unrelated elephants can still form compatible and successful social groups.Elephants have complex social systems that are predominantly driven by ecological factors in situ. Within zoos, elephants are held in relatively static social groups and the factors observed driving social relationships in the wild are largely absent. Little research has investigated the effect of social group factors in zoos on elephant social interactions. The aim of this research was to establish whether there is a relationship between social group factors and social behaviour, in order to identify factors that make elephant herds more or less likely to be compatible. Results will facilitate recommendations for optimum social groupings for zoo elephants. Behavioural data quantifying social interactions were collected between January 2016 and February 2017 at seven UK and Irish zoos and safari parks from 10 African and 22 Asian elephants. Social interactions were split into four categories: positive physical, positive non-physical, negative physical and negative non-physical. Social interactions were related to age (positive physical higher and negative non-physical lower in calves than adults), personality (elephants with higher sociability scores engaged in more positive interactions and less negative interactions), presence of calves in the herd (herds with calves had more positive non-physical), relatedness to other elephants in the herd (positive non-physical were higher when relatives were in the group and negative non-physical were higher between unrelated elephants) and species (Asian elephants engaged in more positive non-physical than African elephants). A greater understanding of factors that may contribute to the success of zoo-elephant social groups is important for individual and herd welfare as it will enable evidence-based decisions which have minimal impact on social structures to be executed. This knowledge will enable proactive management approaches to be undertaken and will thus be paramount in ensuring optimal welfare for elephant herds moving forwards.

Exploring the relationship between personality and social interactions in zoo-housed elephants: Incorporation of keeper expertise

Individual animal personalities affect experiences of zoo environments, and thus potentially welfare. Incorporating keeper knowledge of animal personality in a reliable way has great value in optimising welfare in zoo-housed animals. Assessment of animal personality has been used to predict group compatibility and social relationships in a number of species including rhinoceros, gorilla and chimpanzees, and there is potential to do the same with zoo elephants. This study identified elephant personalities using keeper ratings, and investigated the relationship between personality and social interactions in zoo elephants. Behavioural data were collected over a period of 12 months at seven study facilities (January 2016 – February 2017). Subjects were 10 African (1 male: 9 females) and 19 Asian (3 male: 16 female) elephants housed at zoos and safari parks in the UK and Ireland. Each subject was rated using an elephant personality assessment questionnaire, comprising 21 personality adjectives with a visual analogue scale. Personality assessments were completed by 27 keepers. Reliability across keepers was established for nine adjectives and a principal components analysis revealed three personality components: ‘attentiveness’, ‘sociable’ and ‘engaged with the environment’. Correlations were observed between keeper scores of sociability and social interactions (p < 0.05). Elephants considered more sociable by keepers interacted positively with a greater proportion of elephants in the herd than less sociable elephants (p < 0.05). Current Secretary of States Standards of Modern Zoo Practice (SSSMZP) elephant management guidelines include the need for long-term management plans, including elephant behavioural profiles and herd compatibility assessments. The results show that sociability as identified by keepers relates to social interactions, illustrating the importance of inclusion of personality assessment in management plans. Future work should build on these findings; applying keeper ratings of elephant personality to a larger sample size, and exploring its potential as a predictive tool in compatibility assessments. Such a measure would help to increase the chance of successful social group formation contributing to positive zoo elephant welfare.

Zoo elephant research: contributions to conservation of captive and free‐ranging species

African elephants Loxodonta africana and Asian elephants Elephas maximus are not thriving in many captive settings and are threatened throughout their native ranges. Many zoos support in situ conservation projects and provide opportunities to conduct ex situ research in controlled settings with comparably approachable animals. Zoo elephant projects may facilitate fieldwork with free‐ranging elephants (e.g. development of non‐invasive sampling and analytical tools), which may then also improve the husbandry of elephants in human care. Free‐ranging elephants also benefit from drug therapies and veterinary care when they are orphaned, kept as working elephants or brought in as rehabilitation cases – especially as human–elephant conflicts become more common as a result of ever‐expanding human populations. Much has been learned about the basic biology and husbandry needs of elephants but, often, the more we learn, the more questions arise. There are physiological differences between African and Asian elephants, and this should affect the management of these animals. This paper will provide brief overviews of the current state of knowledge regarding the pharmacology, nutrition, reproduction, sensory biology and diseases (primarily elephant endotheliotropic herpesvirus infections) relevant to elephants with recommendations for future research.

Impact of a new exhibit on stereotypic behavior in an elderly captive African elephant

Stereotypic behavior in zoo elephants is considered an indicator of impaired welfare. The underlying causes are diverse and many aspects are still unexplored. Nevertheless, many zoological institutions take huge efforts to improve the well-being of their elephants. The construction of a new exhibit provides a chance to gain further evidence on the impact of such measures on elephant behavior. We report a significant decrease in the amount and frequency of swaying in an elderly African elephant (Loxodonta africana) after transition to a new enclosure. While we assume that continuous social interactions, increased freedom of choice and appropriate resting locations were critical for the distinct improvement of this individual´s well-being, the only factor that significantly correlated with swaying in this individual was the amount of time per day the elephant group was separated. These factors are in large part independent of enclosure size. Thus, corresponding adaptations in elephant husbandry are also encouraged in facilities without resources for the building of extensive new exhibits and may lead to increased zoo elephant welfare.

Body Condition Scores (BCS) in European zoo elephants (Loxodonta africana and Elephas maximus) lifetimes – a longitudinal analysis

In further improving zoo elephant welfare, diet and feeding regimes are key factors. Together with the encouragement of physical activity, they support the management of weight and the prevention of obesity, which is considered a common concern in zoo elephants. Besides weight monitoring, visual body condition scoring (BCS) has proven a practical tool for the assessment of (zoo) elephants' physical condition. From the individual management as well as the medical perspective, documentation of an elephant´s BCS changes over time might be much more informative than a population-wide crosssectional analysis. We present a compilation of cases where European zoo elephant BCS can be assessed against influencing factors, such as reproductive activity, physical disorders, advanced age, stressful situations and diet adaptations. The present study of the European zoo elephant population describes how various life circumstances and management adaptations are reflected in the BCS of individual elephants, and in population-wide BCS over time. An online archive to build up a reliable, individualbased data basis with minimal additional workload for elephant-keeping facilities is introduced.

Impact of a new exhibit on stereotypic behaviour in an elderly captive African elephant (Loxodonta africana)

Stereotypic behaviour in zoo elephants is considered an indicator of impaired welfare. The underlying causes are diverse and many aspects are still unexplored. Nevertheless, many zoological institutions make huge efforts to improve the well-being of their elephants. The construction of a new exhibit provides a chance to gain further evidence on the impact of such measures on elephant behaviour. We report a significant decrease in both the amount and frequency of swaying in an elderly African elephant (Loxodonta africana) after transition to a new enclosure. While we assume that continuous social interactions, increased freedom of choice and appropriate resting locations were critical for the distinct improvement of this individual´s well-being, the only factor that significantly correlated with swaying in this individual was the amount of time per day the elephant group was separated. Thus, corresponding adaptations in elephant husbandry are also encouraged in facilities without resources for the building of extensive new exhibits and may lead to increased zoo elephant welfare.

Update on Comparative Biology of Elephants: Factors Affecting Reproduction, Health and Welfare.

Asian (Elephas maximus) and African (Loxodonta africana) elephants serve as important keystone, umbrella and flagship species. Despite that, population numbers are declining, due mainly to poachingand habitat destruction. Understanding reproductive mechanisms is vital to effective management, particularly insurance populations in captivity, and to that end, long-term biological databases are key to understanding how intrinsic and extrinsic factors affect reproductive function at individual and population levels. Through decades of hormonal and ultrasonographic monitoring, many unique aspects of zoo elephant reproduction have been identified, including differences in luteal steroidogenic activity, follicular maturation, pituitary gonadotropin secretion, fetal development and reproductive tract anatomy. Reproductive problems also hamper captive propagation efforts, particularly those related to abnormal or lack of ovarian cyclicity. Recent large-scale, multi-institutional studies and use of epidemiological approaches have identified factors important for good welfare and reproduction, which include enrichment, feeding diversity, good elephant-keeper relations, social compatibility, exercise, and not being obese. There are notable differences in reproductive mechanisms between Asian and African elephants, as well as the factors that influence reproduction and welfare, suggesting species-targeted management approaches are needed to maximize fitness. In the first edition, we discussed reproductive function in male and female elephants. Since then, a number of significant advances have been made primarily in female elephants, which will be the focus of this updated review.

Good keeper-elephant relationships in North American zoos are mutually beneficial to welfare

Relationships between animals and their human caretakers can have profound impacts on animal welfare in farms, laboratories and zoos, while human attitudes are important predictors of caretaker behavior towards livestock. In this study, we examined the impact of keeper attitudes about working with elephants on Keeper-Elephant Relationships (KERs) and Bonds (KEBs), and found evidence for reciprocity and welfare benefits to both parties. As part of a large, multi-institutional study of zoo elephant welfare conducted at 60 zoos accredited by the American Zoo and Aquarium Association, blood samples were collected twice monthly for 1 year from 117 African (Loxodont africanus) and 96 Asian (Elephas maximus) elephants for serum cortisol analyses as a measure of well-being. Information was collected via three online questionnaires: 1) a Keeper Survey of 277 elephant keepers about their opinions of and attitudes towards working with elephants and their job satisfaction; 2) an Elephant Behavior Profile Survey where keepers rated a total of 234 elephants on the frequencies of 24 behaviors, and 3) a Keeper-Elephant Bonds Survey in which 209 individual keepers rated the strength of their bond with a specific elephant for a total of 427 keeper-elephant pairings. From the first two surveys, principle components analysis was used to create subscales of keeper attitudes, elephant behaviors and keeper job satisfaction. Component scores were then used as independent variables in epidemiological analyses of elephant mean serum cortisol and mixed model regressions of keeper job satisfaction. For African elephants, risk factors of low serum cortisol included Positive interactions with elephants (p = 0.039), Positive behaviors of elephants (friendly, affiliative) (P = 0.001), and Elephant interacts with public (P = 0.009). Age of the elephant was a small, but significant risk factor for higher cortisol (P = 0.005). For Asian elephants, the risk factors for low cortisol were attitudes indicating social inclusion in elephant groups (Keeper as herdmate, P = 0.039) and Elephant interacts with public (P = 0.006). Latitude of zoo was a predictor of higher cortisol (P = 0.041). Significant predictors of keeper Dissatisfaction with job were weaker Keeper-Elephant Bonds (P = 0.003) and African Species (P = 0.038). Species differences in KERs and KEBs are discussed in terms of differing elephant management factors in zoos. The results provide evidence of the reciprocity of KERs and the mutual benefits of KEBs to both elephant and keeper. These results are relevant for zoo animal management and staff training.

Body condition scores in European zoo elephants (Elephas maximus and Loxodonta africana) – Status quo and influencing factors

Obesity is a common problem in captive elephants. Therefore, physical state monitoring presents a critical aspect in preventive elephant healthcare. Some institutions lack the equipment to weigh elephants regularly, so body condition scoring (BCS) is a valuable alternative tool. As yet, the BCS of both elephant species has not been assessed comprehensively for the European population. Using a previously validated visual BCS protocol, we assessed 192 African (Loxodonta africana) and 326 Asian elephants (Elephas maximus) living in European zoos (97% of the living European elephant population). The majority of elephants were in the upper score categories with 56% of adults assessed in the range 7-10 out of 10. Adult Asian elephants had significantly lower BCS (males: mean 6.2 ± 1.0, median 6.0, range 4-8; females: mean 6.6 ± 1.3, median 6.0, range 3-9) than African elephants (males: mean 6.7 ± 0.7, median 6.0, range 6-8; females: mean 6.9 ± 1.2, median 6.0, range 1-9). Comparison with samples of free-ranging populations (163 Asian elephants and 121 African elephants) revealed significantly lower scores in free-ranging elephants independent of species, age and sex category. Compared to previous reports from captive populations, the European zoo elephant population is nevertheless less obese. In adult Asian elephant females, BCS was significantly correlated to their breeding status with lower scores in current breeders; however, breeding status was also correlated to group size, enclosure size, and a diet with less vegetables. Further attention to zoo elephant weight management is recommended with regular longitudinal monitoring by body condition scoring.

God as Edie: The Knoxville Zoo Elephant Who Crushed and Killed Her Keeper, Stephanie James, 14 January 2011

God as EdieThe Knoxville Zoo Elephant Who Crushed and Killed Her Keeper, Stephanie James, 14 January 2011 Susan O’Dell Underwood (bio) They had to believe she knew not what she’d done. Pent up, spent of a thousand, thousand wasted days,though, maybe she meant that murderous misbehavior,the one myopic tragic move left in her DNA,no longer able to judgedistances or love. In the colonnade of her bones a stampedehad waited for the trunk of her to swing,perhaps, her tusk a wish to brush a human clavicle,let go the cavalcade of snortsher trunk in exhortation held backevery other time before just like a blessing. The lively blithe blonde lifted upwardher final gift, an offering of communion towardthe open grey-pink, wrinkled moutha precious snack, unwitting sacrifice,without a breath of hesitation at the evening’s altar. There is no way to punish this calamity: The keeper’s lovely body fell, it falls, it is falling,the memory of the falling held above all else, [End Page 114] a plodding memory capable of holding every equal sorrowinside that tree-bark skin and lumbering bone and blood,inside the mind inside that massive drudgery of skull. [End Page 115] Susan O’Dell Underwood Susan O’Dell Underwood directs the creative writing program at Carson-Newman University. The author of two chapbooks, her work has appeared in Oxford American, Rock & Sling, Crab Orchard Review, Bellevue Literary Review, and The Southern Poetry Anthology: Tennessee. Her first full-length book of poems, The Book Of Awe, is forthcoming from Iris Press. Copyright © 2018 Berea College

Assessing the dyadic social relationships of female african (Loxodonta africana) and asian (Elephas maximus) zoo elephants using proximity, tactile contact, and keeper surveys

Understanding the affiliative social relationships, or bonds, between zoo elephants has implications for both their welfare and management, yet there is limited work assessing and describing these bonds. Consequently, there is a need for the development of a reliable assessment tool. We used multiple metrics of proximity and tactile contact, as well as keeper surveys, to assess the social bond strength of 41 elephant dyads from 22 different zoos. Survey descriptions of social bond strength were based on previous research and included proximity and separation-reunion behaviors between individuals in a dyad. Approximately half of the elephant dyads in our study were rated as having a “strong” or “strongest” bond by keepers, who showed excellent agreement in their ratings of elephant bond strength (ICC(1,k)=0.82). Elephant dyads that spent more time in proximity (within two elephant body lengths), and those that were more consistent in this behavior across time had an increased predicted probability of being rated as having a “strong or strongest bond” by keepers (p<0.001; p=0.002; respectively). Affiliative tactile contact within dyads, described using duration, diversity, symmetry, and variability metrics, was not significantly related to keeper assessments of dyad bond strength. On average, proximity within dyads occurred more often and was less variable than dyads’ tactile behaviors. Our results suggest that tactile contact may play a more limited role in the maintenance of zoo elephant social bonds than proximity; however, additional research is needed to confirm this. Additionally, this study suggests that keepers are accurately assessing the proximity behavior of their elephants, highlighting the potential of this survey tool to reliably measure the social bond strength of zoo elephant dyads.

Survey of reproduction and calf rearing in Asian and African elephants in European zoos

Acyclicity, conception failure, abortion, stillbirth, dystocia, infanticide and neonatal mortality have all been reported as causes of reproductive failure in zoo elephants. These events are often reported as single case reports or in specific studies focused on a particular stage in the reproductive process. In North America wider surveys of reproduction in the zoo elephant population have been completed and repeated to provide data over a number of years. This study is the largest and most comprehensive study of reproduction in the European zoo elephant population to date. Two questionnaires collected data from throughout the reproductive process from assessing cyclicity to independence of the calf at 5 years old. Information was collected regarding 189 birth events. Many causative and contributing factors such as obesity, infectious disease, husbandry, facilities, stress, behaviour, herd size and social grouping have been proposed. The importance of these was assessed and where possible association identified using statistical analysis. In African elephants, this study found that age, obesity, reproductive pathology and dominance, identified as important risk factors for failure to conceive in the American zoo elephant population were of low importance. The most significant cause in Europe was lack of access to a compatible bull. In Asian elephants reproductive failure was much less common but when it did occur age and reproductive pathologies were significant factors as found in previous studies. Previous studies have found that age, obesity and infanticide were considered as the most important risk factors in the period from birth to rearing. In this survey it was found that herd stability and compatibility, allomothering or maternal experience and management at parturition can significantly influence reproductive success. Elephant Endotheliotropic Herpes virus was confirmed as the biggest cause of calf mortality. This work provides evidence to support changes to elephant management in European zoos in order to encourage development of social and affiliative herd behaviours and improve reproductive success.

Recumbence Behavior in Zoo Elephants: Determination of Patterns and Frequency of Recumbent Rest and Associated Environmental and Social Factors.

Resting behaviors are an essential component of animal welfare but have received little attention in zoological research. African savanna elephant (Loxodonta africana) and Asian elephant (Elephas maximus) rest includes recumbent postures, but no large-scale investigation of African and Asian zoo elephant recumbence has been previously conducted. We used anklets equipped with accelerometers to measure recumbence in 72 adult female African (n = 44) and Asian (n = 28) elephants housed in 40 North American zoos. We collected 344 days of data and determined associations between recumbence and social, housing, management, and demographic factors. African elephants were recumbent less (2.1 hours/day, S.D. = 1.1) than Asian elephants (3.2 hours/day, S.D. = 1.5; P < 0.001). Nearly one-third of elephants were non-recumbent on at least one night, suggesting this is a common behavior. Multi-variable regression models for each species showed that substrate, space, and social variables had the strongest associations with recumbence. In the African model, elephants who spent any amount of time housed on all-hard substrate were recumbent 0.6 hours less per day than those who were never on all-hard substrate, and elephants who experienced an additional acre of outdoor space at night increased their recumbence by 0.48 hours per day. In the Asian model, elephants who spent any amount of time housed on all-soft substrate were recumbent 1.1 hours more per day more than those who were never on all-soft substrate, and elephants who spent any amount of time housed alone were recumbent 0.77 hours more per day than elephants who were never housed alone. Our results draw attention to the significant interspecific difference in the amount of recumbent rest and in the factors affecting recumbence; however, in both species, the influence of flooring substrate is notably important to recumbent rest, and by extension, zoo elephant welfare.

Determining Connections between the Daily Lives of Zoo Elephants and Their Welfare: An Epidemiological Approach.

Concerns about animal welfare increasingly shape people’s views about the acceptability of keeping animals for food production, biomedical research, and in zoos. The field of animal welfare science has developed over the past 50 years as a method of investigating these concerns via research that assesses how living in human-controlled environments influences the behavior, health and affective states of animals. Initially, animal welfare research focused on animals in agricultural settings, but the field has expanded to zoos because good animal welfare is essential to zoos’ mission of promoting connections between animals and visitors and raising awareness of conservation issues. A particular challenge for zoos is ensuring good animal welfare for long-lived, highly social species like elephants. Our main goal in conducting an epidemiological study of African (Loxodonta africana) and Asian (Elephas maximus) elephant welfare in 68 accredited North American zoos was to understand the prevalence of welfare indicators in the population and determine the aspects of an elephant’s zoo environment, social life and management that are most important to prevent and reduce a variety of welfare problems. In this overview, we provide a summary of the findings of the nine papers in the collection titled: Epidemiological Investigations of North American Zoo Elephant Welfare with a focus on the life history, social, housing, and management factors found to be associated with particular aspects of elephant welfare, including the performance of abnormal behavior, foot and joint problems, recumbence, walking rates, and reproductive health issues. Social and management factors were found to be important for multiple indicators of welfare, while exhibit space was found to be less influential than expected. This body of work results from the largest prospective zoo-based animal welfare study conducted to date and sets in motion the process of using science-based welfare benchmarks to optimize care of zoo elephants.

Walking Behavior of Zoo Elephants: Associations between GPS-Measured Daily Walking Distances and Environmental Factors, Social Factors, and Welfare Indicators.

Research with humans and other animals suggests that walking benefits physical health. Perhaps because these links have been demonstrated in other species, it has been suggested that walking is important to elephant welfare, and that zoo elephant exhibits should be designed to allow for more walking. Our study is the first to address this suggestion empirically by measuring the mean daily walking distance of elephants in North American zoos, determining the factors that are associated with variations in walking distance, and testing for associations between walking and welfare indicators. We used anklets equipped with GPS data loggers to measure outdoor daily walking distance in 56 adult female African (n = 33) and Asian (n = 23) elephants housed in 30 North American zoos. We collected 259 days of data and determined associations between distance walked and social, housing, management, and demographic factors. Elephants walked an average of 5.3 km/day with no significant difference between species. In our multivariable model, more diverse feeding regimens were correlated with increased walking, and elephants who were fed on a temporally unpredictable feeding schedule walked 1.29 km/day more than elephants fed on a predictable schedule. Distance walked was also positively correlated with an increase in the number of social groupings and negatively correlated with age. We found a small but significant negative correlation between distance walked and nighttime Space Experience, but no other associations between walking distances and exhibit size were found. Finally, distance walked was not related to health or behavioral outcomes including foot health, joint health, body condition, and the performance of stereotypic behavior, suggesting that more research is necessary to determine explicitly how differences in walking may impact elephant welfare.

Reproductive Health Assessment of Female Elephants in North American Zoos and Association of Husbandry Practices with Reproductive Dysfunction in African Elephants (Loxodonta africana).

As part of a multi-institutional study of zoo elephant welfare, we evaluated female elephants managed by zoos accredited by the Association of Zoos and Aquariums and applied epidemiological methods to determine what factors in the zoo environment are associated with reproductive problems, including ovarian acyclicity and hyperprolactinemia. Bi-weekly blood samples were collected from 95 African (Loxodonta africana) and 75 Asian (Elephas maximus) (8–55 years of age) elephants over a 12-month period for analysis of serum progestogens and prolactin. Females were categorized as normal cycling (regular 13- to 17-week cycles), irregular cycling (cycles longer or shorter than normal) or acyclic (baseline progestogens, <0.1 ng/ml throughout), and having Low/Normal (<14 or 18 ng/ml) or High (≥14 or 18 ng/ml) prolactin for Asian and African elephants, respectively. Rates of normal cycling, acyclicity and irregular cycling were 73.2, 22.5 and 4.2% for Asian, and 48.4, 37.9 and 13.7% for African elephants, respectively, all of which differed between species (P < 0.05). For African elephants, univariate assessment found that social isolation decreased and higher enrichment diversity increased the chance a female would cycle normally. The strongest multi-variable models included Age (positive) and Enrichment Diversity (negative) as important factors of acyclicity among African elephants. The Asian elephant data set was not robust enough to support multi-variable analyses of cyclicity status. Additionally, only 3% of Asian elephants were found to be hyperprolactinemic as compared to 28% of Africans, so predictive analyses of prolactin status were conducted on African elephants only. The strongest multi-variable model included Age (positive), Enrichment Diversity (negative), Alternate Feeding Methods (negative) and Social Group Contact (positive) as predictors of hyperprolactinemia. In summary, the incidence of ovarian cycle problems and hyperprolactinemia predominantly affects African elephants, and increases in social stability and feeding and enrichment diversity may have positive influences on hormone status.