Zoo Elephants Research Articles

Assessment of Body Condition in African (Loxodonta africana) and Asian (Elephas maximus) Elephants in North American Zoos and Management Practices Associated with High Body Condition Scores.

Obesity has a negative effect on health and welfare of many species, and has been speculated to be a problem for zoo elephants. To address this concern, we assessed the body condition of 240 elephants housed in North American zoos based on a set of standardized photographs using a 5-point Body Condition Score index (1 = thinnest; 5 = fattest). A multi-variable regression analysis was then used to determine how demographic, management, housing, and social factors were associated with an elevated body condition score in 132 African (Loxodonta africana) and 108 Asian (Elephas maximus) elephants. The highest BCS of 5, suggestive of obesity, was observed in 34% of zoo elephants. In both species, the majority of elephants had elevated BCS, with 74% in the BCS 4 (40%) and 5 (34%) categories. Only 22% of elephants had BCS 3, and less than 5% of the population was assigned the lowest BCS categories (BCS 1 and 2). The strongest multi-variable model demonstrated that staff-directed walking exercise of 14 hours or more per week and highly unpredictable feeding schedules were associated with decreased risk of BCS 4 or 5, while increased diversity in feeding methods and being female was associated with increased risk of BCS 4 or 5. Our data suggest that high body condition is prevalent among North American zoo elephants, and management strategies that help prevent and mitigate obesity may lead to improvements in welfare of zoo elephants.

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.

The Days and Nights of Zoo Elephants: Using Epidemiology to Better Understand Stereotypic Behavior of African Elephants (Loxodonta africana) and Asian Elephants (Elephas maximus) in North American Zoos.

Stereotypic behavior is an important indicator of compromised welfare. Zoo elephants are documented to perform stereotypic behavior, but the factors that contribute to performance have not been systematically assessed. We collected behavioral data on 89 elephants (47 African [Loxodonta africana], 42 Asian [Elephas maximus]) at 39 North American zoos during the summer and winter. Elephants were videoed for a median of 12 daytime hours per season. A subset of 32 elephants (19 African, 13 Asian) was also observed live for a median of 10.5 nighttime hours. Percentages of visible behavior scans were calculated from five minute instantaneous samples. Stereotypic behavior was the second most commonly performed behavior (after feeding), making up 15.5% of observations during the daytime and 24.8% at nighttime. Negative binomial regression models fitted with generalized estimating equations were used to determine which social, housing, management, life history, and demographic variables were associated with daytime and nighttime stereotypic behavior rates. Species was a significant risk factor in both models, with Asian elephants at greater risk (daytime: p<0.001, Risk Ratio = 4.087; nighttime: p<0.001, Risk Ratio = 8.015). For both species, spending time housed separately (p<0.001, Risk Ratio = 1.009), and having experienced inter-zoo transfers (p<0.001, Risk Ratio = 1.175), increased the risk of performing higher rates of stereotypy during the day, while spending more time with juvenile elephants (p<0.001, Risk Ratio = 0.985), and engaging with zoo staff reduced this risk (p = 0.018, Risk Ratio = 0.988). At night, spending more time in environments with both indoor and outdoor areas (p = 0.013, Risk Ratio = 0.987) and in larger social groups (p = 0.039, Risk Ratio = 0.752) corresponded with reduced risk of performing higher rates of stereotypy, while having experienced inter-zoo transfers (p = 0.033, Risk Ratio = 1.115) increased this risk. Overall, our results indicate that factors related to the social environment are most influential in predicting elephant stereotypic behavior rates.

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.

Elephant Journey: The True Story of Three Zoo Elephants and Their Rescue from Captivity by Rob Laidlaw (review)

Elephant Journey: The True Story of Three Zoo Elephants and Their Rescue from Captivity by Rob Laidlaw (review)

A Comparison of Walking Rates Between Wild and Zoo African Elephants

With increased scrutiny surrounding the welfare of elephants in zoological institutions, it is important to have empirical evidence on their current welfare status. If elephants are not receiving adequate exercise, it could lead to obesity, which can lead to many issues including acyclicity and potentially heart disease. The goal of the current study was to compare the walking rates of elephants in the wild versus elephants in zoos to determine if elephants are walking similar distances relative to their wild counterparts. Eleven wild elephants throughout different habitats and locations in Botswana were compared to 8 elephants at the San Diego Zoo Safari Park. Direct comparisons revealed no significant difference in average walking rates of zoo elephants when compared with wild elephants. These results suggest that elephants at the San Diego Zoo Safari Park walk similar rates to those of wild elephants and may be meeting their exercise needs.

Diagnosis of Tuberculosis in Three Zoo Elephants and a Human Contact - Oregon, 2013.

In 2013, public health officials in Multnomah County, Oregon, started an investigation of a tuberculosis (TB) outbreak among elephants and humans at a local zoo. The investigation ultimately identified three bull elephants with active TB and 118 human contacts of the elephants. Ninety-six (81%) contacts were evaluated, and seven close contacts were found to have latent TB infection. The three bulls were isolated and treated (elephants with TB typically are not euthanized) to prevent infection of other animals and humans, and persons with latent infection were offered treatment. Improved TB screening methods for elephants are needed to prevent exposure of human contacts.

Circadian rhythm of salivary cortisol secretion in female zoo-kept African elephants (Loxodonta africana).

Salivary samples were collected over a 24-hr period from one group of six juvenile (7-12 years) and one group of three adult (24-25 years) African elephant females, Loxodonta africana, and the cortisol concentration was measured in unextracted samples by EIA. Samples were collected during May, June, and November 2012 (n = 147) using cotton swabs at 4-hr intervals from 20:00 to 20:00 of the next day (seven samples per animal in each trial). The animals are kept under standard zoo management: the herd is maintained in their indoor enclosures until 10:00 and then released into the outdoor enclosures until 21:00-21:30 (May/June) and 18:30-19:00 (November). No adult elephant bull was present at the zoo during this time. The results demonstrate a clear diurnal pattern of cortisol secretion with the lowest concentration observed at 20:00 (2.03 ± 0.08 ng/ml saliva) and the peak concentrations at 08:00 (5.26 ± 0.35 ng/ml saliva). Although the cortisol values were higher in the adult cows compared to the juvenile cows in the May-June period, the differences were not significant. However, the values obtained in November from the juvenile group were significantly higher (P < 0.05) than the concentrations measured in this group in June. In conclusion, salivary cortisol in zoo elephants follows a circadian rhythm (sleep-wake cycle) adapted to daily zoo husbandry routines.

An investigation into resting behavior in Asian elephants in UK zoos.

Maintaining adequate welfare in captive elephants is challenging. Few studies have investigated overnight rest behavior in zoo elephants, yet time spent resting has been identified as a welfare indicator in some species. We investigated resting behavior in Asian elephants (Elephas maximus) in UK zoos, with the aim of identifying patterns or preferences in lying rest. Details of standing (SR) and lying (LR) rest behavior were identified by observing video footage of inside enclosures collected for 14 elephants (2 male, 12 female) housed at three UK zoos (Zoo A: 18 nights; Zoo B: 27 nights; Zoo C: 46 nights) from 16:00 to 08:30 (approximately). Elephants engaged in a mean of 58-337 min rest per night. Time of night affected mean duration of LR bouts (P < 0.001); longest bouts were observed between 22:01 and 06:00. Elephants showed a substrate preference when lying to rest; LR was not observed on concrete or tiled flooring. Where sand was available (to 11/14 elephants), all elephants engaged in LR on sand flooring. Only two elephants engaged in LR on rubber flooring (available to 7/14 elephants). Mean duration of rest bouts was greater when a conspecific was within two body lengths than when conspecifics were not (P < 0.01). Our study indicated that elephants show substrate preferences when choosing an area for rest and engage in more rest when conspecifics are in close proximity. The results of this study could be used as a basis for future studies investigating the link between rest and welfare in captive elephants.

Environmental conditions associated with repetitive behavior in a group of African elephants.

Repetitive movement patterns are commonly observed in zoo elephants. The extent to which these behaviors constitute a welfare concern varies, as their expression ranges from stereotypies to potentially beneficial anticipatory behaviors. Nevertheless, their occurrence in zoo animals is often viewed negatively. To better identify conditions that prompt their performance, observations were conducted on six African elephants (Loxodonta africana) at the North Carolina Zoo. Individuals spent most of their time engaged in feeding, locomotion, resting, and repetitive behavior. Both generalized estimating equation and zero-inflated negative binomial models were used to identify factors associated with increased rates of repetitive behavior. Time of day in conjunction with location on- or off-exhibit best explained patterns of repetitive behavior. Repetitive behaviors occurred at a lower rate in the morning when on-exhibit, as compared to afternoons on-exhibit or at any time of day off-exhibit. Increased repetitive behavior rates observed on-exhibit in the afternoon prior to the evening transfer and feeding were possibly anticipatory responses towards those events. In contrast, consistently elevated frequencies of repetitive behavior off-exhibit at all times of day could be related to differences in exhibit complexity between off-exhibit and on-exhibit areas, as well as a lack of additional foraging opportunities. Our study contributes valuable information on captive elephant behavior and represents a good example of how behavioral research can be employed to improve management of zoo animals.

Locomotion in captive Asian elephants (Elephas maximus)

It is of great importance that zoos provide animals with enclosure space and enrichment to replicate their natural existence. The aim of this study was to examine and calculate the total distance travelled and utilisation of enclosure space by the Asian elephants housed at the Royal Melbourne Zoological Gardens (Melbourne Zoo), Victoria, Australia. The distance travelled was calculated via video analysis, using a grid overlay system to manually track an adult bull and four adult cow elephants between 0600 and midnight. The mean daily distance travelled over the 18-hour active period was 9.05±0.61 km, with an individual range of 6.21–15.00 km. In comparison, when living in non-extreme environmental conditions, wild Asian and African elephants have been estimated to travel an average of 5–10 km each day, demonstrating that Melbourne Zoo’s elephants travel at the top end of their wild counterparts’ range of daily travel distances. The techniques used in the present study allow for the approximate calculation of distance travelled by urban zoo elephants, and could potentially be applied to a range of species kept in captivity. Being able to measure distance travelled could be a very useful tool in furthering welfare considerations and management in a captive environment.

Diurnal and nocturnal activity budgets of zoo elephants in an outdoor facility.

The present study examined the activity budgets of 15 African elephants (1 bull, 6 cows, 2 male juveniles, 2 female juveniles, and 4 male calves) living at the San Diego Zoo Safari Park during the summers of 2010 and 2011. Onsite behavioral data (n = 600 hr) were collected for approximately 12 weeks from 0400 to 0830 and 1100 to 2400 during the 2010 and 2011 summer season. Foraging was the most common behavior state during the day followed by resting, and walking. During the evening hours, the elephants spent majority of their time foraging, resting, and sleeping. The average rate of self-maintenance behavior events (dust, wallow, etc.) increased from 0600 to 0700, 1100 to 1500, and from 1700 to 1900. Positive social behavior events (touch other, play, etc.) remained high from 0500 to 2300, with peaks at 0600, 1300, 1500, and 1900. Negative social events occurred at low rates throughout the day and night, with peaks at 0600, 1900, and 2200. The majority of positive behavior events during the daylight and nighttime hours involved the mother-calf pairs. Furthermore, the calves and juveniles initiated approximately 60% of all social events during the daytime and 57% of all social interactions at night. The results of this study demonstrate the differences between diurnal and nocturnal activity budgets of a multi-age and sex elephant herd in a zoological facility, which highlights the importance of managing elephants to meet their 24 hr behavioral needs.

Prenatal passive transfer of maternal immunity in Asian elephants (Elephas maximus)

Asian (Elephas maximus) and African (Loxodonta africana) elephants exhibit characteristics of endotheliochorial placentation, which is common in carnivore species and is associated with modest maternal to fetal transplacental antibody transfer. However, it remains unknown whether the bulk of passive immune transfer in elephants is achieved prenatally or postnatally through ingestion of colostrum, as has been documented for horses, a species whose medical knowledgebase is often extrapolated for elephants. To address this issue, we took advantage of the fact that many zoo elephants are immunized with tetanus toxoid and/or rabies vaccines as part of their routine health care, allowing a comparison of serum antibody levels against these antigens between dams and neonates. Serum samples were collected from 3 newborn Asian elephant calves at birth (before ingestion of colostrum); 2–4 days after birth; and 2–3 months of age. The findings indicate that the newborns had anti-tetanus toxoid and anti-rabies titers that were equivalent to or higher than the titers of their dams from birth to approximately 3 months of age, suggesting that the majority of maternal-to-fetal transfer is transplacental and higher than expected based on the architecture of the Asian elephant placenta.

The Effects of Housing on Zoo Elephant Behavior: A Quantitative Case Study of Diurnal and Seasonal Variation

One of the greatest challenges for zoo managers is ensuring the best possible welfare for zoo elephants. Few studies have focused on behavioral health of elephants over a 24-hour period and across seasons, making evaluations of behavioral variation challenging. This study examined the behavior of two zoo-housed African elephants (Loxodonta africana) over a two-year period to determine the roles of 1) indoor/outdoor housing, 2) time of day, and 3) seasonal variation on activity. Daytime behavioral differences were contrasted with nighttime activity, and across seasons. Significant differences were noted when the elephants were indoors vs. outdoors, between day and night, and between summer and winter, suggesting that evaluations of zoo elephant activity should occur throughout circadian cycles and account for seasonal variability

The effects of GPS collars on African elephant (Loxodonta africana) behavior at the San Diego Zoo Safari Park

The use of tracking devices (e.g., VHF radio collars, GPS collars, ear transmitters) enables researchers to assess activity budgets, species-specific movement patterns, effects of environmental enrichment, and exercise levels in zoo animals. The fundamental assumption in these studies of tagged animals is that attachable tracking devices have negligible effects on the animals’ behavior. The present study examined solitary and social behavior rates, as well as overall activity budgets, in eight African elephants living at the San Diego Zoo Safari Park, Escondido, CA, USA. Each elephant was trained over several months to wear leather collars affixed with GPS units encased in watertight plastic containers. Behavioral data collected while the GPS collars were worn (16 daylight hours, 16 night hours) were compared to behavioral data when the GPS collars were not worn (16 daylight hours, 16 night hours) throughout June and July 2010. No significant differences (P<0.05) in behavior rates or average percent of observation time the subjects were recorded in particular states were found. During the morning hours, while the collars were both worn and not worn, feeding was the most common behavior state (M=44.7±3.8%, M=49.3±15.3%), followed by resting (M=35.5±10%, M=37.3±12%) and walking (M=10±3.1%, M=8.7±1.9%). During the evening hours, feeding remained the most common behavior state for both worn and not worn conditions (M=66.1±12.3%, M=63.3±13.7%), followed by resting (M=17.6±7.7%, M=19.4±9.5%), and sleeping (M=8.1±8.9%, M=7.8±8.1%). This distribution of daily behavior state is similar to previous activity budgets examined in other zoo elephant herds. These results suggest that, with adequate training, GPS collars may have minimal impact on the behavior of zoo elephants.

Causes and Correlates of Calf Mortality in Captive Asian Elephants (Elephas maximus)

Juvenile mortality is a key factor influencing population growth rate in density-independent, predation-free, well-managed captive populations. Currently at least a quarter of all Asian elephants live in captivity, but both the wild and captive populations are unsustainable with the present fertility and calf mortality rates. Despite the need for detailed data on calf mortality to manage effectively populations and to minimize the need for capture from the wild, very little is known of the causes and correlates of calf mortality in Asian elephants. Here we use the world's largest multigenerational demographic dataset on a semi-captive population of Asian elephants compiled from timber camps in Myanmar to investigate the survival of calves (n = 1020) to age five born to captive-born mothers (n = 391) between 1960 and 1999. Mortality risk varied significantly across different ages and was higher for males at any age. Maternal reproductive history was associated with large differences in both stillbirth and liveborn mortality risk: first-time mothers had a higher risk of calf loss as did mothers producing another calf soon (<3.7 years) after a previous birth, and when giving birth at older age. Stillbirth (4%) and pre-weaning mortality (25.6%) were considerably lower than those reported for zoo elephants and used in published population viability analyses. A large proportion of deaths were caused by accidents and lack of maternal milk/calf weakness which both might be partly preventable by supplementary feeding of mothers and calves and work reduction of high-risk mothers. Our results on Myanmar timber elephants with an extensive keeping system provide an important comparison to compromised survivorship reported in zoo elephants. They have implications for improving captive working elephant management systems in range countries and for refining population viability analyses with realistic parameter values in order to predict future population size of the Asian elephant.

Thermal windows on the body surface of African elephants ( Loxodonta africana) studied by infrared thermography

In this study, we examined infrared thermograms in the course of time of six African zoo elephants and observed two phenomena. First, we noticed independent thermal windows, highly vascularised skin areas, on the whole elephants’ body and second we observed distinct and sharply delimited hot sections on the elephants’ pinnae. The frequency of thermal windows increased with increasing ambient temperature and body weight. We assume that the restriction of an enhanced cutaneous blood flow to thermal windows might enable the animal to react more flexibly to its needs with regard to heat loss. With this understanding, the use of thermal windows in heat loss might be seen as a fine-tuning mechanism under thermoneutral conditions.

What do population‐level welfare indices suggest about the well‐being of zoo elephants?

To assess zoo elephants' welfare using objective population-level indices, we sought data from zoos and other protected populations (potential "benchmarks") on variables affected by poor well-being. Such data were available on fecundity, potential fertility, stillbirths, infant mortality, adult survivorship, and stereotypic behavior. Most of these can also be affected by factors unrelated to well-being; therefore, for each, we analyzed the potential role of these other factors. Population-level comparisons generally indicate poor reproduction, and poor infant and adult survivorship in zoos compared with benchmark populations (with some differences between zoo regions and over time). Stereotypic behavior also occurs in c. 60% of zoo elephants; as the population-level welfare index least open to alternative interpretations, this represents the strongest evidence that well-being is/has been widely compromised. Poor well-being is a parsimonious explanation for the diverse range of population-level effects seen, but to test this hypothesis properly, data are now needed on, for example, potential confounds that can affect these indices (to partition out effects of factors unrelated to well-being), and causes of the observed temporal effects, and differences between species and zoo regions. Regardless of whether such additional data implicate poor well-being, our findings suggest that elephant management has generally been sub-optimal. We also discuss the selection and utilization of benchmark data, as a useful future approach for evaluating such issues.

Developmental milestones among African elephant calves on their first day of life

A recurrent issue confronted by zoos is the extent to which animals living ex situ have life history profiles representative of those living in situ. The lengthy lifespan of African elephants hinders collecting proper comparative data, but enough information has been published to conduct preliminary analyses comparing the developmental profile of zoo and wild African elephants on their first day of life. We show that calves born in a zoo stand and walk on their own for the first time at the same age as those born in the wild. Calves born in the zoo take a little longer until first successful nursing, but the difference in age between wild and zoo is not statistically significant. Male and female calves born in zoos develop at the same pace, with data insufficient to compare with wild-born calves. We conclude maternal parity has an effect on the age of first nursing, but not on first standing or walking, because the initiation of suckling requires coordination between two animals. We suggest that available evidence indicates that calves born in the wild and in zoos develop at comparable rates.

How should the psychological well‐being of zoo elephants be objectively investigated?

Animal welfare (sometimes termed "well-being") is about feelings - states such as "suffering" or "contentment" that we can infer but cannot measure directly. Welfare indices have been developed from two main sources: studies of suffering humans, and of research animals deliberately subjected to challenges known to affect emotional state. We briefly review the resulting indices here, and discuss how well they are understood for elephants, since objective welfare assessment should play a central role in evidence-based elephant management. We cover behavioral and cognitive responses (approach/avoidance; intention, redirected and displacement activities; vigilance/startle; warning signals; cognitive biases, apathy and depression-like changes; stereotypic behavior); physiological responses (sympathetic responses; corticosteroid output - often assayed non-invasively via urine, feces or even hair; other aspects of HPA function, e.g. adrenal hypertrophy); and the potential negative effects of prolonged stress on reproduction (e.g. reduced gametogenesis; low libido; elevated still-birth rates; poor maternal care) and health (e.g. poor wound-healing; enhanced disease rates; shortened lifespans). The best validated, most used welfare indices for elephants are corticosteroid outputs and stereotypic behavior. Indices suggested as valid, partially validated, and/or validated but not yet applied within zoos include: measures of preference/avoidance; displacement movements; vocal/postural signals of affective (emotional) state; startle/vigilance; apathy; salivary and urinary epinephrine; female acyclity; infant mortality rates; skin/foot infections; cardio-vascular disease; and premature adult death. Potentially useful indices that have not yet attracted any validation work in elephants include: operant responding and place preference tests; intention and vacuum movements; fear/stress pheromone release; cognitive biases; heart rate, pupil dilation and blood pressure; corticosteroid assay from hair, especially tail-hairs (to access endocrine events up to a year ago); adrenal hypertrophy; male infertility; prolactinemia; and immunological changes.