PSYETA LogoCopies of this journal are no longer available for sale, but our other two journals, Society & Animals and the Journal of Applied Animal Welfare Science, are available and subscriptions are quite affordable. They can be ordered online via our secure order page.

Zoo Husbandry and Research: An Integrated Approach


Author describes how environmental enrichment can be provided to zoo animals in many ways. In the following article the author examines how research and husbandry training procedures enhance the lives of animals at the Roger Williams Park Zoo. He relates how an integrated approach allows the zoo to acquire valuable experimental data and promote optimal animal care while tending to animals' behavioral needs.
zoo animals, training, behavior, behavior change, animal husbandry, animal behavior, feeding habits
About the Author


As animal care professionals, we in the zoological profession assume countless responsibilities. These range from the daily husbandry of our diverse collections, often with respect to the sensitive needs of conservation programs, to the demands of research and education programs. Moreover, as we become intimately involved in the lives of our charges, many of us find it increasingly necessary to develop ways to mitigate the detrimental effects of captivity on animals (Lawrence and Rushen, 1993). At the Roger Williams Park Zoo we are striving to find ways to integrate these practices.

Several months ago we undertook a long term commitment to optimize living conditions for all animals maintained at our facility. This change was marked by the creation of the Environmental Enrichment Committee (EEC), whose mission has three primary objectives: 1. Promote animal welfare - maximize the quality of life of the animals in our care; relieve boredom, stress, and reduce the occurrence of stereotypic behaviors.

2. Maximize reproductive success and survivability - especially of endangered animals (when appropriate).

3. Dramatically improve visitors' educational
experience of the zoo
- promote the image of healthy, well adjusted animals, and demonstrate how they actually live in the wild. The purpose of the EEC is to critically evaluate the quality of existing and future exhibits and holding areas. We develop ways to improve the facilities and their associated husbandry practices, share opinions between various areas of expertise, and plan, execute, and oversee all enrichment projects. Ultimately we seek a reduction in the occurrence of aberrant (stereotypic) behaviors, relieved stress, and a greater degree of natural behaviors in all our animals.

This is undoubtedly a tall order requiring collaborative efforts from everyone involved with animal care, including zoo keepers, veterinary staff, researchers, and ultimately involving the General Curator and the Director. As we work toward our goal; help animals live as healthy and well adjusted representatives of their respective species, we must provide stimulating environments which mimic natural habitats as closely as possible. This is accomplished by researching animals' natural histories to learn about their physical and behavioral needs and design enclosures accordingly.

But even in beautifully constructed "naturalistic" environments, animals can become bored, stressed, and neurotic. Animals in zoos must not be regarded as static monuments to wildlife, but rather as complex and dynamic beings, requiring real opportunities and challenges to accomplish behaviors (Markowitz, 1978,1993). In other words, the behavioral contingencies found in nature must be not be ignored in captivity. We are therefore interested in finding ways to help our animals become active and thinking representatives of their species.

Our research department plays a vital role in this task. Since 1990, we have conducted numerous investigations with our collection, many of which have served to promote enrichment opportunities. These include examinations of the behavior and reproductive biology of white-faced sakis (Pithecia pithecia), cognitive abilities and reproductive biology of African elephants (Loxodonta africana), and concept learning in California sea lions (Zalophus californianus). Not only does our research seek to answer pressing questions concerning our animals and their behavior, but our methods of data collection actually seem to lend themselves directly to the subjects' psychological well-being.

To date, our most effective and ambitious forms of environmental enrichment have emerged from behavioral training procedures originally developed for husbandry and research purposes. We began conditioning some of the animals to work with us in order to reduce the need for stressful (and sometimes dangerous) physical and chemical restraint during veterinary procedures and to facilitate daily animal management practices. We soon discovered these exercises provided benefits of equal importance directly to the animals. Almost serendipitously we found the animals learned to engage in stimulating activities which helped interrupt traditionally monotonous daily routines. We observed that through dynamic and positive interactions with keepers, animals can engage in a sort of occupational therapy and become both mentally and physically stimulated. They become active participants in their own care while helping us learn more about them.


For many years, our three sea lions were managed through an extremely limited husbandry program. The daily care routine consisted of food fish placed in an indoor feeding pool twice per day as the three animals were brought in together to eat. This often resulted in fierce competition as the animals were inadvertently pitted against each other in turbulent struggles for food. Such feedings, although very time efficient for the keepers (typically lasting under a minute in duration), comprised the full extent of human interaction with the animals. Regrettably, the keepers were left with neither records of the individual animal's food intake, nor any other reliable methods to monitor their health. Moreover, the animals learned nothing from this practice except how to fight one another for food and to eat as quickly as possible.

This situation was inadequate for many reasons; not only for the obvious lack of husbandry control, but particularly for the waste of valuable training opportunities. Behavioral training has many benefits. It presents vast opportunities to mentally challenge animals as they work for food as all wild animals must do in order to survive. We decided to create a program to give the sea lions a means to augment their limited behavioral repertoire and provide us with a way to improve our husbandry control.

Since the inception of a training program, the sea lions' dispositions changed dramatically. Once indifferent to or even threatened by human proximity and contact, each has now learned to work closely with keepers and allow a wide range of "hands-on" procedures. This is particularly important because of the nature of pinniped physiology. Like most other marine mammals, sea lions cannot be anesthetized safely or easily (because of an involuntary reflex which causes them to stop breathing), so in the interests of veterinary medicine, it is helpful for them to learn to cooperate with as many procedures as possible. These include full body examinations (including the use of X-ray equipment), the application of ointments and antiseptics to the eyes and skin for the treatment of minor lesions, and even the collection of blood samples.

Cooperation in each of these procedures has been accomplished strictly through the use of positive reinforcement training, a process through which the animals are eager to work for their food. The sea lions typically engage in two training sessions per day, occasions which also serve as their morning and afternoon feedings. They are individually brought into an off - exhibit holding area and worked for approximately five to ten minutes on a selected repertoire of behaviors. These behaviors usually include lying flat and motionless on the floor in order to allow the trainer (or veterinarian) to examine and palpate various parts of the body, a situation which relies on a great deal of mutual trust between animal and handler.

Behaviors are solicited through a combination of verbal and gestural stimuli. Once satisfied with the level of performance, the trainer blows a whistle (conditioned reinforcer) to let the sea lion know he or she is about to receive a food reward. The trainer gives the animal food fish for each correctly performed behavior. At the end of the session, the animal receives the remaining food from the pre-measured diet, along with verbal praise. Although the trainer sets the goals and rules of conduct, the animals have ultimate control over their training. If they decide not to participate (which sometimes happens), we simply end our session and try again later. Any food not earned during training sessions is provided at day's end so the animals are never food deprived. Quite often, our biggest challenge is to make the routines interesting enough to keep the sea lions occupied.


One particularly exciting project is our ongoing study of cognition. In order to address questions concerning the sea lions' complex cognitive abilities, we have conducted a series of tests examining discrimination learning. Such testing is done in lieu of one of the daily testing sessions and involves the use of a modified Wisconsin General Testing Apparatus (Savage, et al., 1994). We began with a simple two-choice object discrimination task (Savage et al., 1994), and are currently working on abstract concept learning (three dimensional and two dimensional oddity). Although our results have been significant (Rice, 1993), it is the actual process of learning which seems most noteworthy for this discussion. There is an obvious sense of excitement evident when a quantum leap in learning occurs. The sea lions suddenly become fixated on their task, take more time to make choices, and show clear anticipation for subsequent trials. This is the closest we have come to providing mental challenges and rewards to our animals like those experienced by their counterparts living in the wild.

We believe such cognitive tasks, in fact, represent parallels to real world situations. In the wild, sea lions must hunt for food in the unpredictable marine environment, engage in complex social interactions during the breeding season, learn to raise and wean pups (requiring fine discrimination abilities for mothers and their offspring to find one another on crowded breeding beaches), and disperse to new breeding areas when necessary (Reidman, 1990). Although we cannot replicate these diverse conditions in the zoo environment, we are able to provide a greater degree of mental stimulation through our research, and the sea lions clearly seem to benefit.

We have also explored the cognitive abilities of our three African elephants. Like the sea lions, they work through positive reinforcement training (earning food treats such as carrots as well as tactile rewards from trainers), and began with a simple two-choice object discrimination task (Savage et al., 1994). More recently, they completed a traditional match-to-sample paradigm in order to test short term memory. Similar to the sea lions, the tests provided these intelligent animals with unique opportunities for mental challenges. In the future, we hope to develop innovative testing situations specifically to investigate social aspects of memory capacity. We ultimately hope to apply new information to the design of captive environments and assist in conservation efforts in the wild.


A good example of the interplay between conservation, research, and enrichment is demonstrated in our work with white-faced sakis. Although white-faced sakis are well represented in zoos, they remain one of the least understood of the South American primates, primarily because so few studies have examined them (Vecchio and Miller, 1993). Because of their accessibility to us (we have one of the largest collections of white-faced sakis in the U.S.), and the advantage of using them as a research model to better understand endangered members of the subfamily Pitheciinae (Chiropotes and Cacajao), we began the first long-term studies on the reproductive biology of this species. The objectives of this research is to document the reproductive cycle in captive white-faced sakis by means of urinary and fecal steroid metabolite measurements; to examine the parental care patterns and development of infants; to describe species typical behavior; and to determine the mating system of these animals in captivity (Savage et al., in press).

In order to chart the hormonal cycles of the females, it is necessary to obtain frequent and regular biological samples from them. Fortunately, non-invasive techniques for collecting urine and feces have been developed (Savage et al., in press; Shideler et al., 1994) that eliminate the need for the collection of daily blood samples, which would involve undue stress and health risks to these animals. Zoo keepers and student volunteers use basic operant techniques to easily collect the necessary samples directly from the animals. Urine and feces are collected simply by placing a plastic container under the female at first light in the exhibit each morning. The sakis, who are rewarded with special food treats for their cooperation, have thus learned to interact positively with their human care givers, gain both immediate and long term benefits for their participation. Laboratory analysis of these samples have given us (and the scientific community) the first information on the length of gestation, ovulatory cycle, and onset of puberty of this species (Savage, 1993), as well as the first discovery (and means to monitor the treatment) of gestational diabetes (Lloyd, 1994) in a non-human primate.

Other aspects of this research include the complexities of the saki social system. Food sharing is an issue of particular interest. Adult primates commonly share food with their offspring, however the sharing of food between adult animals is rare (Feistner and McGrew, 1986). We have observed food sharing between adult white-faced sakis, and are now trying to determine the conditions under which sharing occurs. More specifically, we wonder if the animals are required to perform tasks in order to gain preferred food items, does the difficulty of the task affect their willingness to share those items?

In one such study, sakis are given nuts (in addition to their regular diet), some of which have been shelled and others not shelled. They are then observed to determine how the different nuts are shared. As predicted, the sakis show a marked preference for shelled nuts and a greater tendency to share the unshelled nuts. Furthermore, once effort has been expended to open the nuts, willingness to share decreases. In another situation, the sakis are given a puzzle feeder (a plastic container with holes), which requires them to work to obtain pieces of preferred food items. Again we see sharing is affected by the amount of difficulty required to obtain food and is manifested as competition. We believe such changes in behavior probably reflect a more natural social order. Through this research the sakis gain increased degrees of social complexity, and help us better understand them.


The projects described in this article represent a modest beginning. Our research department and enrichment committee are still quite young and promise to serve as vehicles for enrichment for a long time. In the meantime, husbandry training is applied to the management of animals throughout our zoo. Some of these programs include: tactile desensitization of Mace giraffes (chute and target training), close inspection of the pouch and developing joey in Matchie's tree kangaroos, and crate training of cotton top tamarind and white-faced sakis. Additionally, programs for polar bears, white-checked gibbons, and para wallabies are currently being developed. The primary impetus for each of these programs is to reduce animal stress and improve our ability to care for and understand animals.


Despite the conventional wisdom inherent in the so-called Three R's: Replacement, Reduction, Refinement of animal welfare (back cover of this journal), it seems in certain situations, especially in zoos where captivity is an unavoidable reality, research can play a significant role in the psychological well-being of animals. In such cases, participation in non-invasive experiments provides animal subjects with challenging tasks to supplement limited behavioral repertoires and also helps improve rapport between humans and animals. In zoos, we must always find ways to work with our animals, often for their own benefit. The more we empower the animals to help us care for and learn about them, the more we all benefit.


I would like to thank Tony Vecchio and Dave Wetzel of Roger Williams Park Zoo for their continued support of environmental enrichment endeavors, and Dr. Anne Savage (Research Director) for her many helpful suggestions in the preparation of this manuscript.

Support for the studies reported here are funded by the Rhode Island Foundation, the Institute of Museum Services, and by Conservation Project Support (IC-10182-91, IC-30226-93).


Feistner, A.T.C. and McGrew, W.C. (1986). Food sharing in primates: a critical review. Perspectives in Primate Biology, Vol. 3, P.K. Seth, S. Seth (eds.), New Delhi: Today and Tomorrow's Printers and Publishers.
Lawrence, A.B., Rushen, J. (1993). Introduction. Stereotypic Animal Behaviour, Fundamentals and Applications to Welfare, A. Lawrence, J. Rushen (eds.), Trowbridge: CAB International.
Markowitz, H., (1978). Behavioral Enrichment in the Zoo. New York: Van Nostrand Reinhold Company: p.2.
Markowitz, H., (1993). Power for Captive Animals: Contingencies and Nature. Paper presentation at 1st Conference on Environmental Enrichment, Portland, Oregon.
Reidman, M.,(1990). The pinnipeds: seals, sea lions, and walruses. Berkeley: University of California Press: pp.313-344.
Rice, J.M., (1993). Concept learning in the California sea lion. Paper presentation at the 1st Annual Roger Williams Park Zoo Research Symposium.
Savage, A., (1993). The Development of a Research Program at the Roger Williams Park Zoo. AAZPA Regional Conference Proceedings.
Savage, A., Lasley, B.L., Shideler, S.E. Studying reproductive functioning in captive primates. Proceedings of the XIVth Congress of the International Primatological Society, Ed. A.J Feistner. In press.
Savage, A., Rice, J.M., Brangan, J.M., Martini, D.P., Pugh, J.A. (1994). The performance of African elephants (Loxodonta africana) and California sea lions (Zalophus californianus) on a two-choice object discrimination task. Zoo Biology 13,69-75.
Shideler, S.E., Savage, A., Ortuno, A.M., Morman, E., Lasley, B.L. (1994). Monitoring female reproductive function by measurement of fecal estrogen and progesterone metabolites in the white-faced saki (Pithecia pithecia). American Journal of Primatology, 32(2),95-108.
Vecchio, A., Miller, A., (1993). North American Regional Studbook for the White - Faced Saki (Pithecia pithecia). Providence: Roger Williams Park Zoo.

James M. Rice

Zoo Keeper, Research Associate
Roger Williams Park Zoo
Providence, Rhode Island

  James Rice earned his B.A. in Psychology and Environmental Studies from the University of Vermont in 1988. He has six years experience working in zoological settings, having begun as a marine mammal trainer at the Mystic Marinelife Aquarium, in Connecticut.

  He served as volunteer research assistant in studies of finback whales (off the southern New England coast) and orcas (British Columbia), as well as in the rehabilitation of beach stranded dolphins and seals. He currently works with a wide variety of animals, including California sea lions, polar bears, red wolves, elk, bison, pronghorn, sand hill cranes, and African elephants.

  James' primary interests involve marine mammals, animal behavior, and conservation issues. He thoroughly enjoys being outdoors, especially sailing, sea kayaking, canoeing, watching wildlife, and exploring new places with his wife Cait and dog Daniel.

PSYETA LogoCopies of this journal are no longer available for sale, but our other two journals, Society & Animals and the Journal of Applied Animal Welfare Science, are available and subscriptions are quite affordable. They can be ordered online via our secure order page.