Lance Miller

• Ph.D.
• Vice President at Brookfield Zoo Chicago

Until recently, the sihek (Guam kingfisher, Todiramphus cinnamominus) has persisted entirely in managed care since a breeding program was established in the 1980s. Understanding the growth and developmental milestones of the sihek from hatch to fledging is critical to enhancing conservation efforts and improving management practices that promote po...

For decades, welfare scientists have focused on investigating and mitigating the abnormal behaviors—including repetitive stereotypic behaviors and abnormal stances/postures—displayed by chimpanzees residing in professionally managed settings. In an effort to design feasible and practical welfare assessments, researchers often pool abnormal behavior...

White-bellied pangolins (Phataginus tricuspis) are semi-arboreal mammals from equatorial Africa. Listed as endangered by the IUCN, their population is under severe threat due to illegal hunting for their meat and scales. Many aspects of pangolin behavior, particularly maternal and early pup behavior, remain largely undocumented. Gathering behaviora...

Browsers are animals that consume significant proportions of leaves, twigs, and bark from woody plants. These species have evolved morphological, physiological, and behavioral adaptations to subsist on a specialized diet. In zoos and other managed care facilities, the provision of browse in appropriate amounts helps promote positive animal welfare....

This review discusses how welfare scientists can examine vocalizations to gain insight into the affective states of individual animals. In recent years, researchers working in professionally managed settings have recognized the value of monitoring the types, rates, and acoustic structures of calls, which may reflect various aspects of welfare. Fort...

Although there has been an increase in research studying the impact of housing on zoo animal welfare, there is still a lack of literature regarding the impact of seasonal housing differences on animal welfare. In northern American zoos, animals native to warmer climates inhabit an outdoor habitat during the summer and an indoor habitat during the w...

Intermittent locomotion composed of periods of active flapping/stroking followed by inactive gliding has been observed with species that inhabit both aerial and marine environments. However, studies on the energetic benefits of a fluke-and-glide (FG) gait during horizontal locomotion are limited for dolphins. This work presents a physics-based mode...

In the original publication [...]

Simple Summary Modern zoological facilities have an ethical responsibility to focus on animal welfare. This includes a commitment to the continuous improvement to the care of the animals as well as responding to animal welfare concerns. A modern zoological facility should have an animal welfare program that includes both proactive and reactive meas...

Simple Summary In recent years, animal welfare scientists have focused on developing novel approaches for improving the quality of life of chimpanzees living in zoos, sanctuaries, and laboratories. To evaluate the emotional, physical, and mental states of individual chimpanzees, welfare researchers are encouraged to integrate indicators that can be...

Animal welfare is a priority across accredited zoological institutions; however, historically, research has been prioritized for mammals. Bird-focused studies accounted for less than 10% of welfare research in zoos and aquariums over the last ten years. Due to the lack of scientific publications on bird welfare, zoo scientists and animal practition...

Intermittent locomotion composed of periods of active flapping/stroking followed by inactive gliding has been observed with species that inhabit both aerial and marine environments. However, studies on the energetic benefits of a fluke-and-glide (FG) gait during horizontal locomotion are limited for dolphins. This work presents a physics-based mode...

This research presents a framework to enable computer-automated observation and monitoring of bottlenose dolphins (Tursiops truncatus) in a zoo environment. The resulting approach enables detailed persistent monitoring of the animals that is not possible using manual annotation methods. Fixed overhead cameras were used to opportunistically collect...

Environmental enrichment can be used to improve the welfare of dolphins in zoos and aquariums. Bottlenose dolphins under professional care are typically provided with a range of enrichment that has a variety of features and levels of complexity at various frequencies. In the present study, a subset of data from a larger study entitled “Towards unde...

Behavioural diversity may serve as a positive indicator of animal welfare that can be applied in long-term monitoring schemes in managed settings (eg zoos, laboratories, farms). Behavioural diversity is often higher when animals live in stimulating environments and experience positive events. Unfortunately, welfare researchers have not adopted cons...

The effect visitors may have on the welfare of professionally managed animals is vital to consider. The present study utilized an experimental approach to examine how 360° visitor viewing access (i.e., viewing from all sides of the habitat) impacts the behavior and physiology of Western lowland gorillas (Gorilla gorilla gorilla, N = 7). Data collec...

Penguins exhibited at zoological institutions can be prone to a foot condition known as pododermatitis (or bumblefoot) if they have high levels of sedentary behaviour. Providing penguins with environmental enrichment can increase activity levels by offering opportunities to engage in species-appropriate behaviour such as swimming and locomoting aro...

The way an animal uses its habitat can serve as an indicator of habitat appropriateness for the species and individuals. Bottlenose dolphins (Tursiops truncatus and Tursiops aduncus) in accredited zoos and aquariums experience a range of habitat types and management programs that provide opportunities for dolphins to engage in species-appropriate b...

Accredited zoological facilities are committed to fully understanding the behavioral, mental, and physical needs of each species to continuously improve the welfare of the animals under their professional care and detect when welfare has diminished. In order to accomplish this goal, internally consistent and externally valid indicators of animal we...

This study reports comprehensive clinical pathology data for hematology, serum, and plasma biochemistry reference intervals for 174 apparently healthy common bottlenose dolphins (Tursiops truncatus) and reference values for 27 Indo-Pacific bottlenose dolphins (Tursiops aduncus), 13 beluga whales (Delphinapterus leucas), and 6 Pacific white-sided do...

Bottlenose dolphins are a behaviorally complex, social species that display a variety of social behaviors. Because of this, it is important for zoological facilities to strive to ensure animals display species-appropriate levels of social behavior. The current study is part of the multi-institutional study entitled “Towards understanding the welfar...

In recent decades, animal welfare science has evolved to utilize a multidisciplinary approach to assess the welfare of animals in accredited zoos and aquariums. Science-based animal welfare assessments have become an essential component of management programs and widespread application is expected by animal care professionals. Management practices...

High-resolution non-invasive cetacean tagging systems can be used to investigate the influence of habitat characteristics and management factors on behavior by quantifying activity levels and distance traveled by bottlenose dolphins (Tursiops truncatus and Tursiops aduncus) in accredited zoos and aquariums. Movement Tags (MTags), a bio-logging devi...

Accredited zoos and aquariums continually strive to ensure high levels of animal welfare for the animals under their professional care. Best management practices include conducting research to better understand factors that lead to optimal welfare and then turning findings into practice. The current study is part of the larger Cetacean Welfare Stud...

The goal of the current study was to create reference intervals and values for several common and one potential novel physiological indicators of animal welfare for four species of cetaceans. The subjects included 189 bottlenose dolphins (Tursiops truncatus), 27 Indo-Pacific bottlenose dolphins (Tursiops aduncus), eight Pacific white-sided dolphins...

Cetaceans are long-lived, social species that are valued as ambassadors inspiring the public to engage in conservation action. Under professional care, they are critical partners with the scientific community to understanding the biology, behavior, physiology, health, and welfare requirements of this taxonomic group. The Cetacean Welfare Study was...

This research presents a framework to enable computer-automated observation and monitoring of bottlenose dolphins ( Tursiops truncatus ) in a professionally managed environment. Results from this work provide insight into the dolphins’ movement patterns, kinematic diversity, and how changes in the environment affect their dynamics. Fixed overhead c...

Defining the activity patterns and social relationships of animals can provide valuable information related to animal welfare. Bottlenose dolphins under professional care engage in a variety of social and solitary activities, which may be influenced by conspecifics, time of day, and maternal behaviors. This study examined the social, solitary, and...

Stereotypic behavior has been studied in various species, but little information exists on stereotypies in giant anteaters (Myrmecophaga tridactyla) under professional care. Giant anteaters are known for their solitary nature and well-developed sense of smell. This study examined the effect of conspecifics who were housed off-exhibit on a male gian...

Environmental enrichment is a key component in improving the psychological and physiological well-being of animals under professional care. Environmental enrichment involves the addition of stimuli, including objects and cognitive challenges, into the environment in order to increase species-specific behaviour and provide opportunities for choice a...

Environmental enrichment is an important tool utilized to improve animal welfare in zoological institutions through opportunity for mental and physical stimulation. Many past studies have focused on the impact enrichment has on animal behavior; however, none have conducted preference assessments on enrichment items to examine the relationship betwe...

Animal welfare researchers are committed to identifying novel measures for enhancing the quality of life of individual animals. Recently, welfare scientists have emphasized the need for tracking multiple indicators of an animal’s behavioral, emotional and mental health. Researchers are currently focused on integrating non-invasive physiological bio...

Aggressive interaction is a fundamental property of nonhuman primate social behavior in wild and professionally managed populations. The form, severity, and direction of aggression can vary depending on context and species. In zoo populations, high rates and severe aggression can cause concern for animal health and welfare. In the present study, we...

Currently there are mixed results regarding the ability for media or more specifically video to increase a person's interest in conservation. However, there is a growing amount of evidence that in‐person experiences at a zoo or aquarium can increase a person's interest in conservation. The goal of the current study was to examine the difference bet...

There are numerous studies on environmental enrichment examining its use as a tool to improve animal welfare. However, no past research has examined the relationship between enrichment preference and long-term interaction with the enrichment items. Free operant, paired-choice preference assessments were run to determine the enrichment preferences o...

Modern day zoos and aquariums continuously assess the welfare of their animals and use evidence to make informed management decisions. Historically, many of the indicators of animal welfare used to assess the collection are negative indicators of welfare, such as stereotypic behavior. However, a lack of negative indicators of animal welfare does no...

Yushu Prefecture in Qinghai Province provides some of the largest known stretches of habitat for the Vulnerable snow leopard Panthera uncia in China. People living in these areas are dependent on agropastoralism. Support from local communities is necessary for effective long-term conservation action for snow leopards, but loss of livestock to snow...

Animal welfare research strives to empirically assess how care and management practices impact the health and well-being of animals across diverse settings. This includes agricultural, biomedical, and companion animals as well as animals in professionally managed populations in zoos and aquariums. Tools developed for use with animals in professiona...

Preference assessments are a valuable tool which have been used to determine favorite items in humans and nonhuman animals. In the past, these assessments were predominantly used to evaluate preference in humans with behavioral disorders to utilize favorites as positive reinforcers for behavioral management. More recent research have conducted pref...

The problem solving capabilities of dolphins are suggested to be indicative of advanced cognition. When confronted with a novel problem, dolphins can plan their behavior to create a more efficient strategy than that which was previously modeled. The present study investigated dolphins' ability to plan their behaviors using an interactive apparatus...

While the zoological community strives to provide the best possible living environment for non-human animals, space limitations constrain where zoos can house particular species. Therefore, an individual may live in proximity to animals that impact its behaviour, physiology, reproductive function or overall welfare status. This article examines how...

Recent research shows that using different types of enrichment has little to no impact on how zoo visitors perceive the animals or the enclosure in general. The primary objective of the current research was to examine if viewing naturalistic-looking environmental enrichment (NEE) and unnaturalistic-looking environmental enrichment (UEE) has an effe...

Knowledge of a dolphin's body mass is central to establishing body condition, comparing across individuals, and designing successful management programs. In the present study, sex‐specific prediction equations for estimating body mass were generated from morphometrics (i.e., length and girth) and ages of bottlenose dolphins residing under professio...

African and Asian elephants are popular within zoos, however there is currently limited information on how viewing them impacts zoo visitors. The goal of the current study was to examine the relationship between viewing elephants in zoos accredited by the Association of Zoos and Aquariums and zoo visitors’ reported conservation intent and perceptio...

As the animal welfare community strives to empirically assess how care and management practices can help maintain or even enhance welfare, the development of tools for non-invasively measuring physiological biomarkers is essential. Of the suite of physiological biomarkers, Immunoglobulin A (IgA), particularly the secretory form (Secretory IgA or SI...

To improve the welfare of nonhuman animals under professional care, zoological institutions are continuously utilizing new methods to identify factors that lead to optimal welfare. Comparative methods have historically been used in the field of evolutionary biology but are increasingly being applied in the field of animal welfare. In the current st...

Concern for elephant welfare in zoological facilities has prompted a number of exhibit and management modifications, including those involving enrichment. Knowledge of how these changes impact indicators of welfare, such as elephant movement and behaviour, is crucial for continued improvement of elephant husbandry and care. The present study used o...

Historically, play behavior has been difficult to define. This likely stems from the number of different species, types of play, and context under which it occurs. In 2016, the Chicago Zoological Society – Brookfield Zoo hosted the Psychonomic Society leading edge workshop on the evolutionary and psychological significance of play. Sixteen experts...

In inclement weather, northern zoos are required to provide animals from warmer climates with indoor exhibits. These indoor exhibits are typically smaller, lack natural substrate, and have lower levels of stimulation for the animals. The purpose of this study was to examine the welfare of four reticulated giraffe (Giraffa camelopardalis reticulata)...

Wild bottlenose dolphin (Tursiops truncatus) behavior is impacted by a number of factors including season, time of day, and age. However, less is known about how these factors may influence animals under professional care in zoos, aquariums and marine parks. Management practices such as scheduled feeding times, human interactions, lack of predators...

While the international zoological community is committed to enhancing the welfare of individual animals, researchers have yet to take full advantage of the tools available for non-invasively tracking behavioural and physiological indicators of welfare. We review technology currently being applied in studies of zoo, farm and laboratory animals to r...

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...

The management of African (Loxodonta africana) and Asian (Elephas maximus) elephants in zoos involves a range of practices including feeding, exercise, training, and environmental enrichment. These practices are necessary to meet the elephants’ nutritional, healthcare, and husbandry needs. However, these practices are not standardized, resulting in...

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 suggestio...

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...

Validation test of accelerometer using video analysis. Two Asian zoo elephants wore accelerometers in anklets for two consecutive nights and accelerometer data were compared with video recordings of recumbence activity. Additionally, Subject #2 wore a second accelerometer in the same anklet to test inter-accelerometer reliability. The most notable...

Mean recumbence and standard error for all subjects (n = 72). (DOCX)

Elephants in the wild face several conservation issues. With the rebranding of zoos as conservation and education pioneers, they have the ability to both educate and inspire guests to action. The purpose of this research was to analyze visitor perceptions and attitudes toward elephant conservation and outcomes post-exhibit visit. A one-page survey...

Abstract The opportunity to observe or interact with animals in a zoo is often vital in influencing visitors’ positive feelings towards animals and ultimately their conservation behavior. This study explores the relationship between observed animal behavior and zoo visitors’ responses. A self-administered questionnaire was completed by 717 visitors...

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 stu...

The purpose of this study was to assess the personality of 17 South African cheetahs at the San Diego Zoo Safari Park. A multifaceted approach of observer ratings (rating method), behavioral data (coding method) and hormone monitoring was used to examine individual differences. Knowledge of these individual differences, i.e., personality, is essent...

Until recently, the impact that the presence of conspecifics may have on stereotypic behaviour in naturally solitary species exhibited in zoological institutions has largely been ignored. This study examined the effect of adding a visual barrier between animal holding areas at the Brookfield Zoo on stereotypic head-rolling behaviour in an adult fem...

Zoological institutions use environmental enrichment to increase opportunities for animals to engage in species-appropriate behavior. In these facilities, enrichment for giraffe typically consists of different types of feeders to increase the percentage of time spent foraging. The current study explored the use of scent enrichment as a way to incre...

The maintenance of species-specific behaviors for animals in zoological institutions is of top priority, as this can help ensure high levels of animal welfare. Strict feeding schedules within institutions can often impact natural foraging behaviors of animals, as they are no longer required to seek out or manipulate food items. In the wild, western...

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 201...

A clear understanding of space use is required to more fully understand biological requirements of nonhuman animals in zoos, aid the design of exhibits, and maximize the animals' welfare. This study used electivity indexes to assess space use of two packs of African wild dogs (Lycaon pictus) and the appropriateness of two naturalistic, outdoor encl...

The purpose of this special issue is to highlight the publication trends regarding research in today’s field of comparative psychology. A survey was conducted to determine the research priorities of institutions and researchers currently pursuing research with animals. Over 200 responses were received from 28 different countries representing scient...

Dolphin shows and dolphin interaction programs are two types of education programs within zoological institutions used to educate visitors about dolphins and the marine environment. The current study examined the short- and long-term effects of these programs on visitors' conservation-related knowledge, attitude, and behavior. Participants of both...

Distance sampling principles were utilized to examine population density and abundance for bottlenose dolphins ( Tursiops truncatus ) in the Mississippi Sound. Information was collected during summer and winter to allow for examination of habitat utilization and abundance during two different seasons. Within the study area of the Mississippi Sound...

One of the many goals of zoological institutions is to actively breed endangered species to enhance conservation efforts. Unfortunately, many of these species are not reproducing at high enough levels to sustain populations within zoos. Low reproductive success and high infant mortality are two areas of concern for some of these species. Collecting...

Behavioral research within zoological institutions (zoos and aquariums) has a long history that has helped to increase basic scientific knowledge and to facilitate the ability of institutions to make informed animal management decisions. Kleiman (1992) stated that "behavior research in zoos has enormous potential to contribute positively to the sci...

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 negli...

Much controversy surrounds the welfare of elephants within zoological institutions. Among the many concerns are lack of exercise and the prevention of sedentary health and welfare issues due to smaller exhibits in comparison to the home-range sizes for elephants in Africa and Asia. While many scientists have used GPS to examine distances travelled...

Regurgitation and reingestion (R/R) is an abnormal behavior observed in great apes analogous to rumination syndrome in humans. A majority of the research on R/R in non-human primates has focused on gorillas and chimpanzees with little information relating to other species that also engage in this behavior. In addition, studies on R/R in non-human p...

Many publications within the field of zoo animal welfare have stated the importance of decreasing stereotypic behavior (e.g., pacing) to help ensure a positive visitor experience. The idea behind these statements is that visitors want to see animals engaged in natural behavior. Additionally, it is thought that watching an animal exhibit species-app...

1. Distance sampling principles were utilized to examine population density and abundance for bottlenose dolphins (Tursiops truncatus) in the Mississippi Sound. Information was collected during summer and winter to allow for examination of habitat utilization and abundance during two different seasons. 2. Within the study area of the Mississippi So...

Stereotypic behavior is observed in many species within zoological institutions. Attempts to reduce such behavior typically involve some form of environmental enrichment that provides opportunities for species appropriate behavior or some degree of control within the environment. However, environmental enrichment has never been completely successfu...

Atlantic bottlenose dolphins (Tursiops trucatus) are found in zoos and aquaria throughout the world. As the number of facilities with dolphin shows and interaction programmes increases, it becomes more important to understand the effects of such programmes on dolphin behaviour. The present study examined the short-term effects of dolphin shows and...

Many of the threats to bottlenose dolphins are anthropogenic factors including overfishing, high-speed boats, chemical runoff, and noise pollution. Having a thorough understanding of the behavior and behavioral patterns of these animals can help with conservation plans to protect this species. This study examined the behavioral states and behaviora...

Abstract  Over the last 10 to 15 years, zoos and aquariums have set out to influence visitors' conservation-related knowledge, attitudes, affect, and behavior. In 2000, the Institute for Learning Innovation collaborated with Disney's Animal Kingdom (DAK) on a comprehensive baseline study conducted to assess the outcomes of a DAK experience on visit...

With the growing trend in zoos to build complex, naturalistic exhibits comes the potential for exhibits to be so densely vegetated or complex that animals are not easily seen by zoo visitors. This can negatively impact the visitor's visiting experience and the zoo's ability to communicate conservation and education messages. Over the past 9 years,...

Zoological institutions typically exhibit dolphins in educational programs such as dolphin shows and interaction programs. The goal of these programs is to entertain visitors while increasing their conservation-related knowledge, attitude and behavior towards dolphins and the marine environment. The purpose of the current study was to examine dolph...

Measuring the impact of anthropogenic factors on marine mammals is critical to the conservation of these species. Recently, the effect of personal watercraft on marine mammal behaviour and well-being has become a topic of increasing concern. The purpose of this study was to examine the immediate effects of high-speed personal watercraft on Atlantic...

Until recently, little attention has been focused on the influence of social interactions and the presence of conspecifics on stereotypic pacing in captive carnivores. This study examined the effect of adding a visual barrier between two tiger (Panthera tigris) exhibits on stereotypic pacing behaviour. Continuous sampling was used to record the dur...

Landsat Thematic Mapper (TM) data were used to classify forested areas within the historic distribution of the endangered cotton-top tamarin (Saguinus oedipus) in Colombia. This species continues to be threatened by habitat destruction, and we observed a 31% decrease of the forested habitat within the tamarins' historic distribution in 1990-2000. I...