stimulating semiosis: animal interpretation in environmental enrichment
While great improvements in habitat design have brought more comfort to animals on display in zoos worldwide, the focus of most renovations has been to enhance the spatial, visual, auditory, and sometimes chemical resemblance of the exhibit to its occupant’s natural habitat. Efforts focused the physical imitation of wild habitats have neglected the importance of dynamism—opportunities to confront and interpret unexpected stimuli and situations—that is as much a part of many animals’ adaptive environments as the trees and rock and birds. Even in the now “mainstream” field of environmental enrichment, efforts focus on static elements of animal habitats or one-time alterations to routines (Ben-Ari 2001: 173). These admirable endeavors still fail to offer sustained stimulation of individual animals’ interpretive abilities, and thus the persistent problem of “boredom” remains unsolved. Recently, efforts have begun to remedy such oversights, and a few zoos have already implemented a broad range of changes which attempt to respect and provide for the semiosic as well as biological needs of their animal residents. But such progressive attitudes toward animals as interpreting subjects with a genuine need for novelty and variation remains the exception, while researchers and keepers alike continue to express inexplicable surprise upon discovery of captive animals’ preference for novelty and challenge.
“Until the 70's and 80's, most zoos housed animals in bare, barred cages and ignored the crushing boredom that caused big-brained animals like primates, big cats and elephants to twitch, bob their heads or groom obsessively, or sit motionless, seemingly defeated.” (Stewart 2002)
Luckily, for most captive animals this is no longer an acceptable lifestyle. Zoos around the world are coming more to resemble condensed samples of the most diverse habitats on earth, catering to the unique needs of their animal inhabitants, rather than displaying animals in circus-like amusement-parks focused on human entertainment. Along with a prominent revolution in physical habitat design, researchers are starting to incorporate elements of animals’ wild environments which provide less tangible benefits to promote well-being (Stewart 2002). Kathy Carlstead provides Hawaiian honeycreepers at the Honolulu Zoo with flowers and live insects. The results have been, apparently, surprising:
Despite the plentiful supply of nectar available from a feeder in their cage, the birds seem to enjoy extracting nectar from the flowers. And instead of just eating their usual daily bowl of fly larvae, the birds hunt down and catch fruit flies that Carlstead raises for them. (Ben-Ari 2001: 172)
Carlstead’s experiment resulted in the goal of all environmental enrichment programs: “[the birds’] behavior became very diverse” (Kathy Carlstead, qtd. in Ben-Ari 2001: 174). What is more surprising than the honeycreepers’ apparent preference for an engaging and challenging activity is the researchers’ surprise at this response. The tone of amazement to be found in similar reports indicates assumptions about animal capacities that, despite recent innovations and improvements in captive habitats, still prevents their keepers from fully meeting the needs of animals for whom “physiological and psychological welfare may be inextricably linked” (Van Metter et al. 2008: 8). While mainstream life-sciences may just now be coming to embrace the reality of animal psychology and subjectivity, it is a topic that zoosemiotics has addressed for decades. When Elia Ben-Ari states “the importance of providing animals with an ever-changing or rotating array of stimuli and behavioral opportunities” (Ben-Ari 2001: 174), she is attending to the interpretive capacity of animals that zoosemiotics has insisted on since its inception.
Discussions within environmental enrichment research of the importance of novelty highlights the most specifically semiotic aspect of captive animals’ comprehensive needs. The importance of variation among stimulus objects, feeding methods, and in daily routines, indicates something that Aleksi Turovski, and before him Heine Hediger, knew almost instinctively: animals have a psychological need to interpret the world around them (Hediger 1968; Turovski 2000). In Turovski’s words, “all forms of animal life are united semiotically by the need for impression” (Turovski 2000: 384). For captive animals, opportunities to respond to novel and unexpected stimuli provide for what might be termed an animal’s semiosic needs. Creating a “natural” environment in captivity is the ostensible goal at most zoos, but this requires more than the construction of an elaborate, static stage on which an animal can be expected to perform “species appropriate behaviors” (Van Metter et al. 2008: 7). A wild environment is dynamic, and presents its living inhabitants with conditions at once habitual and, to varying degrees, unpredictable. Animals have adapted to survive and flourish in environments where actions are not pre-determined by an unchanging routine of occurrences. They are not born into their habitats with a set of pre-programmed responses to unvarying and predictable stimuli, intolerant or unaware of everything outside the range of their familiarity. If this were true, captivity itself would be untenable. Studies of captive animals’ responses to environmental enrichment demonstrate that they are not only capable of interpreting novel stimuli and incorporating them into their perceptive and behavioral repertoires, but that they need to do so in order to exhibit the signs of physiological and psychological well-being (Ben-Ari 2001; Van Metter et al. 2008; Carlstead 1991; Vargas and Anderson 1999; Shepherdson et al. 1998).
The Novel and the Natural
An important question provoked by environmental enrichment research is whether “novel” outweighs “natural” in determining the benefit of stimuli and activity to captive animals. Debates about what extent zoos should take the imperative of “natural” to are heated, especially when it is a question of “letting nature take its course” that leads to the preventable death of an animal or its young (see, for instance, Madrid 2011; and Purvis 2008). As in other areas of semiotic research, zoosemiotics offers a possible approach to such problems in which the question of what is natural versus what is unnatural is eclipsed by its focus on the animal as an interpreter of its environment. By analyzing environmental enrichment programs from the perspective of the interpretive opportunities they provide for individual animals, rather than making value judgments based on the naturalness of a distinctly artificial environment, such efforts can be judged according to their efficacy and ethical responsibility toward the animals they are meant to benefit.
“[T]he methods and reasons for implementing enrichment, as well as assessments of its effectiveness, may be as varied as the animal subjects of enrichment studies themselves” (Van Metter et al. 2008: 7), however, they generally include efforts that can be categorized according to the element of the captive habitat that they are intended to augment. Below are presented three examples of enrichment, each focusing on a different aspect of the captive environment: in the first, enrichment involves increased types or amounts of stimuli to which species are particularly receptive, based on their species-specific perceptive capacities; second, examples of experimental feeding methods aim to encourage species-appropriate behaviors and reduce stereotypy; and third, activities that are designed to relieve boredom and expose animals to a wider range of inter-specific interaction. The focus of this overview will not be on the “naturalness” or species-appropriateness of the enrichment, though the latter is an important factor in designing enrichment programs, but rather on the interpretive opportunities provided by specific enrichment and how animal responses to them highlight previously neglected semiosic needs.
Stimuli ∙ The flowers and live fruit flies that Kathy Carlstead provides for honeycreepers is one of many examples of enrichment that introduces stimuli found in a species’ wild environment to their captive habitats. Other instances of this particular type of enrichment involve the highly successful introduction of prey-animal scents, especially blood and feces, to carnivore habitats (Van Metter et al. 2008; Carlstead 1991; Vargas and Anderson 1999), which encourages hunting behaviors that may be further augmented by feeding methods (see below). Stimulating a predator with the scent of prey is fairly straightforward and unsurprising, but similar excitement has been produced by smells that would never occur naturally in an animal’s wild environment:
Everyone knows that cats love catnip—but cats are also drawn to cumin, nutmeg, and other spices. “I’ve seen jaguars rolling in nutmeg to the point that they were more yellow than black…I saw the same jaguar get all drooly about cumin.” (Jill Mellen, qtd. in Ben-Ari 2001: 174)
In this example, the question of naturalness seems obviously secondary to the animal’s apparent engagement with—even enjoyment of—the spice smells. A similar conclusion has been drawn in regard to primates at the Philadelphia Zoo, who were given “busy boxes” designed as toys for human infants but which proved equally interesting to red-bellied tamarins. Despite not occurring in animals’ wild environments, the introduction of these stimuli did not provoke fear or other negative responses but rather curiosity, engagement, and a reduction in stereotypical behaviors and lethargy (Ben-Ari 2001: 176). Similar positive effects have been observed after the introduction of other “unnatural” stimulus objects, like beer kegs and cardboard boxes, to lion, tiger, and bear habitats (Van Metter et al. 2008; Stewart 2002; Carlstead 1991). Key to the success of this and, as we will see, all kinds of enrichment, is variation and novelty:
…after a while the animals were no longer engaged by the toys. But… “if you put something different in the animal’s cage they get interested in that too.” (Renner, qtd. in Ben-Ari 2001: 176)
These environmental enrichment experiments, and others like them, demonstrate that stimuli found in an animal’s wild environment is neither the only appropriate, nor even the most beneficial, addition to their captive habitats. Novelty and variation appear to be equally important, for an animal will eventually become habituated, or bored with a stimulus, just as we would expect a human to. This supports Turovski’s insistence that animals have a semiosic need for impression—opportunities to interpret novel and varied stimuli and situations. Animals need not only to be embedded comfortably in their traditional environments, but to be given the opportunity to actively interact with them by responding to new and unexpected stimuli.
Feeding ∙ In a survey of sixty-seven zoos, 83% reported feeding their bears only once per day, usually depositing the food in a pile in the animal’s holding area. Similar methods are the norm for most zoo animals, but feeding activities offer some of the most obvious opportunities to enrich animal environments and stimulate complex and varied behaviors. At many zoos, this has led to the introduction of live food that carnivores may stalk and catch, like black-footed ferrets who hunt live hamsters at mealtime (Vargas and Anderson 1999: 263). Some species eating habits are likely to be off-putting to zoo visitors, and so researchers and keepers have introduced alternative activities that simulate the experience of wild feeding without the risk of offending those who “get all bent out of shape by a tiger eating a carcass, even though its natural in the wild” (Lattis, qtd. in Stewart 2002). Tigers at the Bronx Zoo engage in simulated hunting, in which “the animals hunt for the sources of dung and blood smells and pull on balls attached to powerful springs, to mimic the experience of dragging freshly killed prey” (Stewart 2002). Again, the positive response of tigers to this abstract hunt indicates their ability to incorporate novel stimuli and behaviors into their routines, and to respond positively to objects and situations that may (to their human keepers) mimic nature, but which are certainly not “natural”.
Emphasizing the necessity of novelty is Carlstead, Seidensticker, and Baldwin’s comparative study of feeding methods. In the habitats of three captive bears of different species, the researchers experimented with three novel varieties of feeding methods and analyzed the influences of each method on the bears’ activity. Their findings indicated a striking reduction in stereotypy only in correlation to the feeding method in which food is scattered and hidden around the bears’ exhibits, encouraging foraging behavior (Carlstead et al., 1991: 14). Altering the feeding structure to include multiple daily feedings, as well as installing a mechanical feeding device operating at irregular intervals “recognizes the high motivation of bears to feed, but for the bear these means of acquiring food are not behavior-contingent” (Carlstead et al., 1991: 13). This study again highlights the importance of providing interpretive opportunities for captive animals, for while the other experimental feeding methods provided one-time novelty, the effectiveness of the method that initiates foraging in the bears stimulates a complex interaction with the environment:
Foraging behavior is strongly controlled by the stimuli in an animal’s environment. While searching for food there is an interdependency between the stimuli an animal encounters in its environment and the behavior and the consequences of its behavior. (Carlstead et al., 1991: 13)
This stimulus-behavior feedback, in which bears are observed to modify their behavior in response to changes in environmental stimuli, provides precisely that kind of interpretive opportunity which satisfies what Turovski referred to as the semiotic need for impression. For the bears in this study, searching for food in hidden places not only reduces the prevalence of stress indicators, but also presents opportunities for food objects and hiding places to be tailored to the unique foraging abilities of different bear species. The great effectiveness of this feeding technique in reducing undesirable stereotypic behaviors speaks to the importance of meeting the semiosic as well as physiological needs of animals, and it is a clear indication that there is more to the significance of feeding than nutrition.
Activity ∙ For animals in captivity, opportunities and motivation for physical activity may be seriously reduced compared to their wild counterparts. In order to address this, zoos may incorporate multiple levels and different types of spaces in their habitats to encourage movement and exploration (Van Metter et al. 2008; Ben-Ari 2001; Carlstead et al. 1991), others take animals for walks around the facilities and even rotate the location of their exhibits periodically (Nolan 2011: 1271), and some zoos have implemented complex exercise regimens as part of general enrichment programs (Yeates 2008: 1). The effects of specially designed exercise regimens have not been widely studied, but improvements in the physical health of animals engaging in such programs has been observed by keepers and researchers (Yeates 2008: 6; Ben-Ari 2001: 174). This type of enrichment leads directly to the question of training as an appropriate stimulating activity for captive animals, which often provokes a negative response from both animal-rights activists (who, to be fair, generally disapprove of zoos in the first place) (see Animal Rights Uncompromised, n.d.; Ember, n.d.; and Panaman 2008) as well as those who insist on a naturalistic approach to animal captivity (Carlstead et al. 1991: 13). Too often, it is assumed that there is no distinction between training, which can provide engaging stimulation for captive animals and enhances their bonds with handlers and researchers, and performance, which exploits animals’ abilities for human amusement. When the question is not one of human entertainment, but of animal enrichment and quality of life, the discussion takes on a more nuanced tone. “Although perhaps more controversial than other approaches, training can also provide opportunities for enrichment” (Ben-Ari 2001: 174). Though comparative research on trained and un-trained captive animals is lacking, professionals have noted a difference in some species, among which trained individuals “seem much more attuned to their environment and are more active” than their untrained counterparts, even when living in the same facility (Ben-Ari 2001: 174).
Training is doubtlessly among the most stimulating inter-specific semiotic interaction captive animals may engage in, and the novel scenarios animals find themselves in can offer a uniquely complex series of interpretive opportunities (Ben-Ari 2001: 174). Heine Hediger stressed the importance of training, not only for the safety and engagement of the animals, but for the invaluable insights that it offers trainers and researchers into the minds of captive animals (Hediger 1968). The goal for many zoos today, as the Central Park Zoo’s animal curator puts it, is to “get inside animals’ brains” (Dr. Don Moore, qtd. in Stewart 2002), not only to satisfy human curiosity but in order to make their captive lives more rich, comfortable, and rewarding (Stewart 2002; Ben-Ari 2001: 177). Training presents an opportunity for communication between captive animals and humans that may not occur regularly in wild environments, but which should not be discarded as a form of enrichment so long as it respects animals unique needs and is intended to improve their lives, both in the short term and as a result of greater human understanding of their perceptions and behaviors.
Prospects for Zoosemiotics
Resistance to conclusions about animals’ semiosic needs is evident even in the literature on environmental enrichment. In their paper that analyzes the effects of stimulus objects on captive lions and tigers, Van Metter, Harriger, and Bolen make the enigmatic statement that, “If enrichment is to improve psychological well-being via the reduction of ethological needs…then its positive effects must continue even when the animal is not exposed to the enrichment item” (Van Metter et al. 2008: 14). It is as though they expect the one-time exposure to a novel stimulus to flip some switch in the animal’s brain that forever improves its mental health. Their conclusion, “that on-going enrichment may be necessary to maintain behavioral gains,” seems at once stingy and obvious. But it does underscore the significance of a dynamic environment rather than one that only resembles nature physically, and the researchers recommend a range of stimuli to further enrich the big cats’ environments—from food-stuffs that fully engage carnivore jaws and teeth, to multi-level habitats and “opportunities for olfactory stimulation with both familiar and novel scents” (Van Metter et al. 2008: 15, italics mine).
Providing captive animals with species-appropriate physical habitats is extremely important to their comfort and well-being, and renovations to static elements of artificial environments have made a dramatic difference in the experience of both the animals and their human visitors (Stewart 2002). Environmental enrichment programs aim to build on the success of such renovations to address the persistent problem of boredom, which manifests itself in lethargy, stereotypical behaviors, and sometimes physiological detriments to animals’ well-being (Van Metter et al. 2008: 8; Ben-Ari 2001: 173; Carlstead et al. 1991: 3). What environmental enrichment research demonstrates, more than almost anything else, is the need animals have to be exposed to novel and varied stimuli in order to exercise their full range of capacities, which includes interpretive abilities:
“I don’t think you can sit back any longer and say that animals are going to be content or in a state of good well-being if you just supply their basic needs—their food and a clean, healthy environment,” Shepherdson says. “It’s absolutely clear…that animals need more than that.” (Shepherdson qtd. in Ben-Ari 2001: 173)
The something more that they need was anticipated by Heine Hediger, whose writings had a decisive influence on zoo biology as well as zoosemiotics. With the development of environmental enrichment programs that aim “to improve the psychological and physiological well-being of captive animals by providing environmental stimuli that help meet the animals’ behavioral and psychological needs” (Ben-Ari 2001: 172), there is a great opportunity for these two fields that claim Hediger as a founding father to come together and share knowledge and methods for investigation. The semiosic capacity of animals has been the subject of zoosemiotics proper since Thomas Sebeok founded the study in the 1960s, but it has remained a fringe topic even in fields where those capacities are most on display to human observers. The research being done in zoosemiotics already could be of great value to the discourse of environmental enrichment, both in its focus on animal communication and Umwelt, and in the broader ethical and philosophical questions surrounding zoos and captivity in general (see, for instance, Mäekivi et al., Forthcoming). Zoos themselves offer a unique opportunity to observe and engage with a huge number of different species, and are thus a great potential laboratory for zoosemiotic research itself. Developments in environmental enrichment, and the growing push to institutionalize and mandate it in accredited zoos (Ben-Ari 2001: 175) has created an occasion for zoosemiotics to contribute to a highly visible area of research, while also taking advantage of the close observation and, perhaps, experimentation opportunities at hand in the zoo environment.
It is unfortunate that various ideological and practical obstacles have kept the living conditions of captive animals fairly dismal for most of human history, but changes in attitudes and assumptions about animal’s minds are slowly generating improvements. Greater understanding and respect for the semiotic capabilities and needs of animals creates opportunities for zoo animals to live richer lives, and for zoosemiotics to contribute more visibly to both public and academic discourse about animals.
"Animal Rights Uncompromised: Zoos." www.peta.org. People for the Ethical Treatment of Animals. Web. 20 Apr. 2012. <http://www.peta.org/about/why-peta/zoos.aspx>.
Ben-Ari, Elia T. "What's New at the Zoo?" BioScience 51.3 (2001): 172-77. Print.
Carlstead, Kathy, John Seidensticker, and Robert Baldwin. "Environmental Enrichment for Zoo Bears." Zoo Biology 10.1 (1991): 3-16. Print.
Cloete, Carin, Onnica Mogogane, and Mankwe Sebati. "A Change in Perspective: Providing Enrichment for Hamadryas Baboons." The Shape of Enrichment 17.3 (2008): 1-3. Print.
Embar, Wanda. "Zoos." Animal Cruelty - Zoos. Vegan Peace. Web. 20 Apr. 2012. <http://www.veganpeace.com/animal_cruelty/zoos.htm>.
Hediger, Heini. The Psychology and Behaviour of Animals in Zoos and Circuses,. New York: Dover Publications, 1968. Print.
Madrid, Cienna. "Cash Cows." The Stranger. Index Newspapers, May 2011. Web. 15 Apr. 2012. <http://www.thestranger.com/seattle/cash_cows/Content?oid=8078780>.
Mäekivi, Nelly, Silver Rattasepp, and Kadri Tüür. "Posthumanism and Human-Animal Relations: The Cases of Zoos and Fishing." Forthcoming 2013.
Nolan, R. Scott. "Designing Zoo Habitats That Promote Animal Well-being." Journal of the American Veterinary Medical Association 239.10 (2011): 1266-286. Print.
Panaman, Roger. "How to Do Animal Rights - Zoos." How to Do Animal Rights. Animalethics.org, Apr. 2008. Web. 20 Apr. 2012. <http://www.animalethics.org.uk/zoos.html>.
Purvis, Andrew. "Germany's Polar Bear Cub Quandary." Time. Time, 09 Jan. 2008. Web. 24 Apr. 2012. <http://www.time.com/time/world/article/0,8599,1701828,00.html>.
Shepherdson, David J., Jill D. Mellen, and Michael Hutchins. Second Nature: Environmental Enrichment for Captive Animals. Washington: Smithsonian Institution, 1998. Print.
Steward, Barbara. "Recall of the Wild; Fighting Boredom, Zoos Play to the Inmates' Instincts." The New York Times. The New York Times, 6 Apr. 2002. Web. 10 Apr. 2012. <http://www.nytimes.com/2002/04/06/nyregion/recall-of-the-wild-fighting-boredom-zoos-play-to-the- inmates-instincts.html?pagewanted=all>.
Turovski, Aleksei. "The Semiotics of Animal Freedom: A Zoologist’s Attempt to Perceive the Semiotic Aim of H. Hediger." Sign Systems Studies 28 (2000): 380-87. Print.
Van Metter, J.E., M. Dana Harriger, and Rosina H. Bolen. "Environmental Enrichment Utilizing Stimulus Objects for African Lions (Panthera Leo Leo) and Sumatran Tigers (Panthera Tigris Sumatrae)." Bios 79.1 (2008): 7-16. Print.
Vargas, Astrid, and Stanley H. Anderson. "Effects of Experience and Cage Enrichment on Predatory Skills of Black- Footed Ferrets (Mustela Nigripes)." American Society of Mammalogists 80.1 (1999): 263-69. Print.
Carlstead is currently undertaking research into the cortical steroid levels of animal provided with enrichment to ensure that this is indeed the case (Ben-Ari 2001: 176).
