Kristen E. Lukas

Case Western Reserve University | CWRU · Department of Biology

Giraffe skin disease (GSD), a condition that results in superficial lesions in certain giraffe (Giraffa spp.) populations, has emerged as a potential conservation threat. Preliminary findings suggested that individuals with GSD lesions move with greater difficulty which may in turn reduce their foraging efficiency or make them more vulnerable to pr...

Evaluating how primates in human care function within their social environment is important for understanding and optimizing their management and welfare. The neuroendocrine hormone oxytocin is associated with affiliation and bonding, suggesting it can be used to evaluate the affiliative nature of social groupings. When paired with cortisol concent...

In the wild, piranhas are thought to feed in groups. Previous studies on piranhas in aquariums have variously observed either social attraction or aggressive dominance. The Rio São Francisco piranha (Pygocentrus piraya) is the largest species of piranha. It is rare in aquarium collections and its social and feeding behaviors have never been studied...

Noise can be a known stressor but our understanding of its effects on animals living in zoo environments remains limited. Although exposure to loud, chronic noise may be expected to negatively impact welfare, providing access to quiet areas to escape loud noise may buffer these negative effects. In this study, we explored the benefits of access to...

Local communities living on the borders of protected areas can be key drivers of environmental degradation. Community‐based conservation initiatives seek to use sustainable activities as a strategy for mitigating these degradative behaviors while improving livelihoods but must be scalable to the site and sustainable over time. Teacher training, as...

Activity budgets characterize the distribution of behavior over a specified time period. In some cases, having comparable data from free-ranging populations can help inform the management of wildlife in zoos and sanctuaries. For example, although variations exist across subspecies, seasons, and study sites, diurnal activity budgets for free-ranging...

Repetitive pacing behavior is exhibited by many species in zoos and is particularly prevalent in carnivores with large home ranges, such as bears. Pacing can be a behavioral indicator of poor welfare, however, understanding this behavior can be challenging. As many bears that pace are singly housed, efforts to systematically examine and ameliorate...

The aims of this study were to determine the current prevalence of regurgitation and reingestion (R/R) and gain an insight on the occurrence of coprophagy in the Association of Zoos & Aquariums (AZA) gorilla (Gorilla gorilla gorilla) population. To do this, an online survey was sent to all AZA accredited gorilla institutions in 2018. This survey co...

In natural environments, bear behavior follows seasonal patterns but the zoo environment differs from the natural environment in several ways, including the presence of zoo visitors. Although typically difficult to disentangle, we were able to tease apart the effects of seasonal changes and visitor density on the visibility and behavior of 10 bears...

Choice-based design allows animals in human care opportunities to move at will between multiple interconnected spaces. Some evidence suggests providing environmental choice confers benefits to animals, but there is a dearth of research in this area with large carnivores. To understand the effects of this design strategy on large felids, behavioral...

Long-term, multi-institution evaluations have become a reliable assessment tool for evaluating patterns of wounding in zoo-living primates, informing on each species’ respective care and population management. For western lowland gorillas (Gorilla gorilla gorilla) there has been no detailed reports focused on mixed-sex groups, the most common socia...

Chimpanzee conservation is dependent on addressing key threats such as habitat degradation, which is fueled by collection of firewood in Uganda's Kibale National Park. To address this threat, sustained behavior change that reduces dependence on fuelwood is needed. One of the greatest challenges for conservation education programs and behavior chang...

Positive reinforcement training (PRT) is associated with increases in species-typical behavior and decreases in stereotypic and abnormal behavior in participating animals. Physiological changes following PRT, for example, increases in oxytocin (OXT) and/or decreases in cortisol (CORT), may facilitate these behavioral changes. This study evaluated s...

Strategies to enhance animal welfare in zoos and aquariums must be balanced with guest experience and animal visibility. Various strategies are used to accomplish these goals, including rotating animals through habitats and providing access to off-exhibit areas. Exhibit rotation has been linked with increased activity levels, investigation, and fee...

Cognitive testing of primates in zoos is becoming increasingly common. Cognition experiments are generally thought to be beneficial as they provide participants with an opportunity to engage in species‐specific cognitive functioning, perhaps more so than with traditional forms of environmental enrichment. However, testing may increase competition a...

Stereotypic pacing behavior is exhibited by many species in zoos, particularly carnivores with large home ranges, such as bears. Most zoos wish to reduce stereotypical behaviors, but currently there is no standardized method to quantify pacing across institutions. Without a common method to measure pacing, successful attempts to alleviate it cannot...

The neuroendocrine hormone oxytocin, which is an important physiological driver of social behavior and bonding, is increasingly being measured in conjunction with behavior to better understand primate sociality. To date no data are available on oxytocin concentrations within the genus Gorilla; however, as a result of their close genetic relatedness...

Delineating patterns of morbidity can reveal management practices in need of reassessment to improve individual welfare, as well as population health and sustainability. We reviewed medical records from 38 North American zoological institutions for 276 slender lorises, slow lorises, and pottos born between January 1, 1980 and December 31, 2010. Thi...

The neuroendocrine hormone oxytocin, which is an important physiological driver of social behavior and bonding, is increasingly being measured in conjunction with behavior to better understand primate sociality. However, no data are available on oxytocin concentrations within the genus Gorilla, even though the members of this genus are of great int...

Given the difficulties of conducting regular endocrine and veterinary assessments of animals, behavioural observations are often the most commonly used tool to assess the welfare of animals in human care. Behavioural measures, inexpensive and convenient to collect, also have their challenges, such as ensuring the behaviours of interest are reliable...

Zoo-housed bears are prone to exhibiting stereotypic behaviors, generally considered indicators of negative welfare. We explored the effects of a variable-time feeding enrichment schedule on behavioral indicators of welfare in four bear species at Cleveland Metroparks Zoo. We distributed the diets of eight bears in one of five enrichment items, for...

Conservation education requires a multidisciplinary approach that ideally incorporates iterative monitoring to inform decision making and facilitate achievement of conservation goals. Despite their value and importance, evaluations of conservation education programmes are often challenging to conduct, and are published infrequently. In this study t...

High-speed video analysis was used to quantify two aspects of gait in 10 zoo-housed polar bears. These two variables were then examined as to how they differed in the conditions of pacing versus locomoting for each bear. Percent difference calculations measured the difference between pacing and locomoting data for each bear. We inferred that the hi...

Applying environmental education in primate range countries is an important long-term activity to stimulate pro-conservation behavior. Within captive settings, mega-charismatic species, such as great apes are often used to increase knowledge and positively influence attitudes of visitors. Here, we evaluate the effectiveness of a short-term video an...

Films, as part of a larger environmental education program, have the potential to influence the knowledge and attitudes of viewers. However, to date, no evaluations have been published reporting the effectiveness of films, when used within primate range countries as part of a conservation themed program. The Great Ape Education Project was a year-l...

Over evolutionary time, light from the sun, moon, and stars has provided organisms with reliable information about the passage of time; but modern artificial lighting has drastically altered these cues. Evidence is accumulating that exposure to light at night—particularly blue wavelengths—from computer screens, urban light pollution, or as an occup...

Positive reinforcement training (PRT) has become a widely used tool in improving the ease with which husbandry and veterinary procedures are performed for animals under human care. PRT provides positive social interaction, cognitive stimulation, and choice, in addition to desensitization towards potentially stressful situations. As a result, PRT ha...

At Cleveland Metroparks Zoo (Cleveland, OH, USA) a male black-footed cat was frequently observed to exhibit repetitive locomotor behaviour and spent a large portion of his day off exhibit. As part of a collaborative effort between animal care and research staff, a stepwise intervention strategy was developed to decrease the subject's repetitive loc...

The use of enzyme immunoassays (EIA) for the non-invasive measurement of glucocorticoids provides a valuable tool for monitoring health and welfare in sensitive species. We validated methods for measuring fecal glucocorticoid metabolites (FGM) using the response to veterinary exams for four species of callitrichine monkeys: golden lion tamarin (Leo...

In North American zoos, male gorillas are often housed in all-male (bachelor) groups to provide socialization for males not managed in breeding groups. These groups exhibit long-term cohesion and stability and males in bachelor groups are no more aggressive than males in mixed-sex groups. Previous studies have shown that aggression in male gorillas...

In North American zoos, male gorillas are often housed in all-male (bachelor) groups to provide socialization for males not managed in breeding groups. These groups exhibit long-term cohesion and stability and males in bachelor groups are no more aggressive than males in mixed-sex groups. Previous studies have shown that aggression in male gorillas...

Pacing behaviour is complex and identifying the motivational basis for pacing and designing an effective remedial strategy can be challenging. Details of the behaviour may provide insight into the motivational basis of behaviour and should be carefully examined. A long-term observational study of pacing by a female Malayan sun bear (Helarctos malay...

Zoos play a unique role in wildlife conservation, particularly in the area of conservation education. Because of their popularity and flagship status for broader conservation issues, great apes may prove to be one of the most important educational conduits in zoos. In 2002, we surveyed knowledge of and attitudes toward African apes in visitors to t...

Although wild primates are known to modify behavior in response to thermal stress, less is known about behavioral thermoregulation in zoo-housed primates. Zoo exhibits expose individuals to unique thermal environments and may constrain the thermoregulatory strategies available to individual animals. In this study, we observed a group of seven colob...

Patterns of mortality in captive animals can reveal potentially problematic care practices or other risk factors that may negatively impact animal health and population sustainability. We reviewed death records (necropsy and/or histopathology reports) for 367 lorises and pottos born between 1980 and 2010 that were housed in 33 North American zoos a...

In the wild, western lowland gorillas travel long distances while foraging and consume a diet high in fiber and low in caloric density. In contrast, gorillas in zoos typically consume a diet that is low in fiber and calorically dense. Some items commonly used in captive gorilla diets contain high levels of starch and sugars, which are present at lo...

In the wild, western lowland gorillas consume a diet high in fiber and low in caloric density. In contrast, many gorillas in zoos consume a diet that is high‐calorie and low in fiber. Some items commonly used in captive gorilla diets contain high levels of starch and sugars, which are minimal in the natural diet of gorillas. There is a growing conc...

The long-term management of male gorillas in zoos is a significant challenge. The demographics of the population - specifically a 50/50 sex ratio and the desire to form breeding groups that contain a single male and multiple females - necessitates housing a majority of adult males outside of mixed-sex groups. The primary approach for socially housi...

Non-human primates occasionally exhibit behaviours thought to occur only in captivity that are considered abnormal. In particular, hair-plucking behaviour occurs across many species of mammals and birds. This study was the first to assess the phenomenology, demography and aetiology of this behaviour in captive gorillas across the Association of Zoo...

Zoos and related facilities in North America currently manage five species in the primate family Lorisidae: the greater (Nycticebus coucang), Bengal (N. bengalensis) and pygmy (N. pygmaeus) slow lorises, red slender loris (Loris tardigradus), and potto (Perodicticus potto). We used an online survey to describe institutional housing and husbandry pr...

African elephants (Loxodonta africana) and black rhinoceroses (Diceros bicornis) are charismatic mammals that help draw visitors into zoological institutions. Because they evolved in the same habitat utilizing similar food resources, the two species have many physiological similarities yet behaviorally remain very different. Limitations of the zoo...

Very little research has explored regurgitation and reingestion (R/R) in orangutans. We first aimed to determine the prevalence of R/R in the North American zoo population through a survey of accredited institutions. We report the prevalence of R/R in orangutans >4 years of age as 35% with some sex and species differences. Additionally, survey resp...

One way to address the problem of small sample size in zoo research is to conduct a study involving multiple institutions. However, when conducting behavioral research, it can be difficult for one investigator to travel to each institution or for staff at individual institutions to find time to collect behavioral data. This study validates keeper a...

This study explored how the physical context of a species enclosure might affect visitor exploration of the exhibit space. Tracking and timing studies were conducted in 2 different designs of an exhibition space focused on African apes to determine if the new, more naturally designed exhibit was explored in a manner different from the former, more...

Studying the effects of moving animals to new enclosures is of value to both captive managers and to scientists interested in the complex interplay between environment and behavior. Great apes represent some of the greatest challenges in this regard. Given the cognitive sophistication of these species and the substantial investments in new primate...

Manipulable substrates promote species-typical behavior and decrease abnormal behavior in a variety of primate species. However, the effects of providing litter to arboreal primates are not as well studied, and there is little information specifically concerning enrichment for guenons. To inform the captive management of an under-studied species, w...

Much of what is known about development in cercopithecine primates is derived from studies of baboons Papio sp and macaques Macaca sp. Two closely spaced births at Cleveland Metroparks Zoo enabled us to describe the development of single infants representing two little-studied species: the Wolf's guenon Cercopithecus pogonias wolfi and Allen's swam...

Empirical measures of animal behavior and space use within the captive environment can provide critical information about animals’ requirements, preferences and internal states. The trend toward naturalistic environments has shown promise in terms of behavioral benefits for animals such as great apes, and there have been several studies of the effe...

This paper emerged from discussions following the Bachelor Gorilla 2000 Workshop Facility Design sessions. Although many ape facility design features are common to all gorillas, the purpose of this paper is to provide an overview of special needs of bachelor gorillas. For example, managing escalating aggression between maturing or silverback males...

In both free-ranging and captive western lowland gorillas, a silverback provides protection and leadership, mediating conflict within a group. In the wild, when a dominant silverback dies the group will disperse or transfer to a solitary male, unless a subsequent male is present to inherit the group. In captivity, studies have focused on groups con...

Depictions of chimpanzees as caricatures can lead people to think these animals are not endangered and is a problem for conservation and welfare efforts.

While personality and temperament assessments are becoming more common in animal science as a means for predicting behavior patterns, they are virtually unstudied in exotic animals outside of chimpanzees. We assessed behavioral profiles of 119 male gorillas using the Gorilla Behavior Index (GBI) and paired this assessment with behavior data on 25 m...

Chimpanzees and gorillas are the two most common species of great ape in captive facilities in North America. This study examined patterns of space use by 14 gorillas and six chimpanzees housed in similar non-naturalistic environments at Lincoln Park Zoo in Chicago, IL. The location of each individual was recorded in relation to elements of the env...

The authors conducted an evaluation of visitor knowledge and conservation attitudes toward African apes at Chicago's Lincoln Park Zoo. Using S. R. Kellert's and J. Dunlap's (1989) analysis of zoo visitor knowledge and attitudes as a model, they modified and administered a survey to 1,000 visitors to the ape facility. On average, visitors correctly...

Male mammals show considerable variation in their association (e.g. single-male, multi-male, all-male groups) and relationship (e.g. affiliative versus intolerant) patterns. Although a number of primates have been observed to form all-male groups, studies of the social dynamics of these groups are limited. This study examined the social interaction...

A primiparous mother and her infant were subjects of a longitudinal behavioral study at Lincoln Park Zoo in Chicago, Illinois. From November 1998 to November 1999, we collected a total of 100 hr of focal nonhuman animal instantaneous point sampling and all occurrence data on the mother and her infant. After 8 months, we introduced the 4-member foca...

The social housing of males is of particular importance for captive managers of polygynous species. In this work, we highlight nine areas we believe are important to the successful formation and maintenance of all-male gorilla groups. Although more data are still needed to complete our understanding of these groups, the general picture that emerges...

Hand preferences for a coordinated bimanual task were assessed in a sample of 31 captive gorillas (Gorilla gorilla) and 19 captive orangutans (Pongo pygmaeus) and were compared with chimpanzee (Pan troglodytes) hand preferences in subjects that were matched on the basis of age, sex, and rearing history. The task required that the apes remove food f...

To determine the effects of relative novelty on captive gorilla behavior, the regular alternation of two groups between complex naturalistic enclosures was studied at Zoo Atlanta. A continuous behavioral change sampling method was used to obtain information on behavior, and instantaneous scans at 10-min intervals provided information on the locatio...

Although various aspects of gorilla nest building have been described in wild populations, nest-building behavior of captive gorillas has not been subject to much scientific review. We observed nest building in 17 gorillas during three periods: summer baseline, winter baseline, and winter treatment, in which the amount of available nesting material...

Concern over a lack of breeding success in a pair of white-cheeked gibbons (Hylobates leucogenys) prompted a four-part study of gibbon behavior and physiology at the Lincoln Park Zoo. Data were collected to determine the female intermenstrual interval (IMI) and identify periods of peak receptivity. Subsequent behavioral data were gathered during bo...

Urinary androgen and corticoid levels were measured for 52 captive male Western lowland gorillas to examine age-related variance and potential differences resulting from various social situations. Significant diurnal variation was present in both hormones. Age-related differences in androgens revealed that males experienced two stages of androgen i...

Gorillas live in polygamous harem groups, generally composed of one male, several adult females, and their offspring. With an equal numbers of male and female gorillas born in captivity, however, housing gorillas in social breeding units inevitably means that some males will not have access to female social partners. Thus, the future of the captive...

Regurgitation and reingestion (R/R) is a common phenomenon in captive lowland gorillas (Gorilla gorilla gorilla), but it has never been reported in wild populations. Although changes in diet have been shown to reduce the behavior, little is known about the underlying mechanisms that lead to its development and maintenance. In this paper, a comparat...

Ph.D. Terry L. Maple

To test whether milk consumption facilitates performance of regurgitation and reingestion (R/R) in captive gorillas, an experiment was conducted in which milk was removed from the gorilla diet at Zoo Atlanta. The study was conducted using a withdrawal design (BTB), in which a baseline period (B) of 10 days was followed by a treatment period (T) of...

A review of Foraging for Survival: Yearling Baboons in Africa, by Stuart A. Altmann. Chicago: The University of Chicago Press, 1998, 608 pp, $70.00, hardbound.

Psychology instructors often visit zoos with their classes to teach about observational data collection methods and animal behavior. Unfortunately, they do not generally introduce the positive reinforcement training techniques used in Zoos as models of applied operant conditioning. In this article, we describe a partnership between Zoo Atlanta and...

To assess the current status of research in zoos and aquariums, a 36-item survey, which replicated and expanded upon an earlier survey [Finlay and Maple, 1986], was sent to 173 American Zoo and Aquarium Association (AZA) institutions. A response rate of 71% was achieved after a second mailing. The results show that the role of research in AZA insti...

To assess the current status of research in zoos and aquariums, a 36-item survey, which replicated and expanded upon an earlier survey [Finlay and Maple, 1986], was sent to 173 American Zoo and Aquarium Association (AZA) institutions. A response rate of 71% was achieved after a second mailing. The results show that the role of research in AZA insti...

The behavior of nine lowland gorillas (Gorilla gorilla gorilla) living in three social groups at Zoo Atlanta was compared in an indoor holding area versus an outdoor exhibit. Focal animal data were collected for each animal during 15 min observation sessions, alternating between indoors and outdoors. A variety of solitary and social behaviors diffe...

Synthetic work research is designed to simulate complex work activities by requiring participants to perform several concurrent tasks. The current project consisted of 2 studies in which adults of different ages performed 4 tasks during 25 sessions in a synthetic work situation in 5-min periods across 3 days. Large age differences were evident in t...

M.S. Terry L. Maple