THE APPLICATION, USE, AND EFFECTS OF TRAINING AND ENRICHMENT VARIABLES WITH JAPANESE SNOW MACAQUES (Macaca fuscata) AT THE CENTRAL PARK WILDLIFE CENTER

Jennifer Goodwin, Wild Animal Keeper
Central Park Wildlife Center
930 Fifth Avenue
New York, NY 10021-7095

ABSTRACT

       Unquestionably, training programs and enrichment activities are important to enhance the lives of captive animals, in both zoos and research facilities. This paper focuses on the training and enrichment of Japanese macaques (Macaca fuscata); it describes the monkeys, their exhibit and holding area, and several aspects of the program at the Central Park Wildlife Center in New York City. The implementation of the program was spurred by a need to achieve maximum safety for animal keepers, as well as enhancing the well-being of our animal collection. I conclude that through the use of a training and enrichment program, such as the one I have been involved with, we have helped to eliminate stress and boredom, as well as decrease agonistic and stereotypic behaviour caused by these factors among captive animals.

INTRODUCTION

      The concept of enrichment has evolved greatly since 1925, when Yerkes first wrote about "the use of apparatus for animals to play with, as an addition to traditional enclosures." According to the 1996 U.S. Wildlife Regulations, all institutions and facilities maintaining nonhuman primates must "develop, document, and follow a plan for environmental enhancement adequate to promote the psychological well-being of non-human primates." The enrichment of captive animals should decrease boredom and stress, as well as encouraging playfulness in these animals.

       Since the environmental stimuli in captive facilities differ significantly from those in the wild, it is not a surprise to us that captive animals frequently demonstrate separate behaviours when compared to their counterparts in the wild. However, an atypical behaviour should not immediately be defined as an abnormal or stereotypic behaviour because it may be an animal's attempt at adapting and coping with its known environment.

      Since 1925, the concept of enrichment has evolved and expanded to include almost any variable that will affect the perception of the animal in its environment; these variables include good and bad, natural and artificial, edible and non-edible, and otherwise. Besides promoting the well-being of an animal, the addition of training and enrichment programs act to aid the observer or researcher to recognize, understand and encourage the behaviours, social interactions, and other activities of many animals, in both captivity and in the wild.

      As we know, the snow monkey, of northern Japan, is an arboreal and terrestrial dweller, subsisting primarily on fruit, but also eating leaves, insects, seeds, buds, flowers, and bark, among other things. Withstanding the snowy winters of sometimes -30⁰F, these monkeys are typically tough, active, gregarious, noisy, imitative, and curious, like many of the species in the family of cercopithicines. With character traits such as these, the macaque is an ideal model for a successful training and enrichment program, such as ours at CPWC.

WHY WE NEED A TRAINING PROGRAM

      Three years ago, we were using four people--the snow monkey keeper plus three other available keepers--to "bring in the monkeys" at closing time. One keeper was needed to man the shift door inside the holding area while the other three "herded" the monkeys in from the exhibit; the keepers do a head count and a recount of the troop before locking up and leaving the area.

      As a preventive measure, all primates are considered to be carriers of zoonotic diseases--whether they have test-proven positive or negative--and, therefore, it is in the zoo's best interest to implement a "protected contact strategy" in order for the macaques to voluntarily shift in at closing time and to eliminate the risks taken of keepers being in the exhibit with the macaques. This strategy is already successfully used with our Polar bears, as well as our colobus monkeys.

      To shift the monkeys in to their holding area at night was only the first phase of the training pro- gram; with that success, future goals will hopefully include such endeavours as voluntary cage restraint and venipuncture.

CPWC MACAQUE EXHIBIT AND HOLDING FACILITY

      Our troop of snow monkeys currently consists of three males and seven females, all are now sexually mature--their ages ranging from five to twenty-three years. Of the ten monkeys, four of them were born at our facility (five additional males--also born here--were transferred to another zoo as a bachelor group upon reaching sexual maturity in order to successfully decrease group aggression, rather than dividing the troop into alternately-exhibited groups).

      The outdoor exhibit is a large island of manmade rock with several smaller islands on the south end; with the exception of a rocky surface ("the beach") connecting the island to the indoor holding area, the exhibit is surrounded by water--the complete exhibit area covers 11, 680 square feet. Besides the rocky crevices and ledges, two waterfalls, and large branches and logs, there are several planters throughout the exhibit which now hold grass and thorny Barberry shrubs--the shrubs were initially planted to deter the monkeys from destroying and eating them, but they have managed to eat around the thorns without killing off the plants! Besides the macaques, the exhibit also houses swans fish, frogs, and turtles, as well as migrating wild ducks.

      The holding area is hidden from the public's view inside a "cave-like" structure. It is a series of four cages with a removable restraint cage in between the second and third cage--creating an "L"; within each of these cages are "benches" or shelves at varying levels. The whole indoor cage space for the macaques, not including the keeper alley, measures at 160 square feet. For optimal cleaning and disinfecting the walls have been tiled and the floors have been cemented and pitched; there are one or two shift doors per contiguous cage and one exterior shift door each in cages one through three

       Prior to executing any type of training with our macaques, modifications within the exhibit and holding areas were necessary. The vestibule outside of the exhibit shift doors--which is hidden from the public's view-has been outfitted with lights, heaters, and a video camera; a "hotwire" spans the exhibit perimeter, and large spotlights have been installed around the outside of the exhibit as well. These additions have made monitoring animals' movements and behaviours easier for staff.

THE TRAINING PROGRAM PROTOCOL

       For over a year, we were offering the monkeys access to their "enriched" holding area during exhibit hours, at which time they were allowed to come and go as they please to reinforce their trust in the keepers and reacquaint them with their holding area as a "positive" place to be. Initially, we attempted the training from inside the holding area. At the end of the day a keeper would stand inside with special "treats" or "rewards"--such as grapes or pieces of banana--for the monkeys, who upon entering the area were rewarded and shifted in for the night; the monkeys who were not shifted inside were brought in by the keepers as per our previous protocol. However, after several months this proved unproductive because the keeper/animal bond appeared to be breaking down, in addition to the fact that no marked progress was noted with the voluntary shifting of the monkeys.

      Therefore, a different and more aggressive approach was decided upon after a "time-out" period. Temporarily, we have now decreased the amount of on-exhibit enhancements--with no access to their holding area during exhibit hours--and instead of entering the exhibit at closing time, the keepers-- through vocal and visual cues--herd the animals from outside the exhibit in to their enriched holding area when the auditory cue has been given (in this case, a whistle is used}.

      While this second strategy still has keepers herding the animals indoors, it has proven to be a rapid success so far; we have eliminated the danger of staff in the exhibit with the monkeys and we are using one less staff member to accomplish this. Our final goal is to have the monkeys responding to the auditory cue without the presence of keepers in front of the exhibit.

ENRICHMENTS

      An enrichment sheet has been prepared and is frequently updated as needed to include miscellaneous items that we can choose from to give to the entire troop of monkeys, who are allowed a maxi- mum of three-and-a-half quarts of edible enrichments from that list per day.

      Although a regimented and printed enrichment schedule may be ideal in most situations, our facility has adopted a "fill-in" spreadsheet to document the enrichments offered and how they were received; the keeper may pick and choose enrichments for that day and may look back over the previous days' sheets to see what items and objects were used, as well as how the animals responded to them. Although the downside of this system is someone forgetting to update the "log," I think it is over- shadowed by the advantages of both increased staff involvement and new ideas for enrichment, as well as more flexibility with the enrichment schedule.

      "Presentation is everything!" And although offering a different type of fruit or vegetable into an environment everyday is enriching, the concept goes well beyond that when you consider in what shape the food is cut, or is it left whole? Whether it is frozen, cooked, raw, or even what the food is presented in--is it in a box, a bag, a toy, or otherwise? We can "play" with textures and smells, as well as aesthetic appearances; but with such a broad range of variables why limit yourself to just edible items; or even if an edible item is not always eaten, maybe it is cheap and plentiful enough to become a successful enrichment as a toy or substrate-like unfavored browse. The development of non-edible enrichments can be more challenging to the zoo keeper than that of food items when considering the prolonged use, interest, and durability of an object from the animal's viewpoint.

      With respect to enrichments which are not successful or possibly even have a negative effect, it is important for the animal to be able to make these distinctions and to exercise its mind by making choices and learning through positive and negative experiences. However, care should be taken to not let the animal associate the enrichment-giver with negative stimuli, which would destroy any progress that the keeper has completed training and bonding with the animals. Negative stimuli is provided to contrast the positive, not to stress or frustrate the animal; generally it may be provided through an uncontrolled or natural occurrence.

       Negative stimuli may include thunder and lightening, blimps, or even offering an unfavored food item. Allowing a monkey to experience both the "good" and the "bad" is a concept I observed in a video from the National Zoo based on the wild release programs with Golden Lion tamarins (Leontopithecus rosalia rosalia), in which the they experienced simulated thunderstorms and keepers flew cut-out images of large predatory birds overhead in preparation for life in the wild. A second example of negative stimuli being used with primates is the snow monkey troop which was relocated to a Texas sanctuary; once in Texas they were trained and conditioned to be wary of the indigenous harms like cacti and rattlesnakes. Such stimuli--in our macaques as well as the troop from Texas, and the tamarins in the video--has resulted in spurring natural behaviours such as distress calls or defensive postures.

      Therefore, when looking at the effects of enrichment items, we should consider work versus play, positive versus negative, edible versus non-edible, and psychological versus physical. Do these items promote natural behaviours, stimulating the animals to use their brains as well as their hands? Besides the effect an item has on an animal, the cost, durability, and practicality should be looked at as well.

EDIBLE TREATS AND ITEMS

      Food plays an important role in enrichment programs--as it does in our daily lives--because there are so many tastes, smells, textures, and items to choose from. In addition to our macaques' daily diet--currently consisting of seeds and nuts, leaf eater or .'monkey" chow, and assorted fruits and greens--they are allowed up to three-and-a-half quarts of miscellaneous edible enrichments per ten monkeys a day. These items are approved and accounted for by the Wildlife Conservation Society's staff nutritionist, Dr. Ellen Dierenfield, with the appropriate changes made for high-calorie treats like peanut butter or opportunistic items such as fresh-cut browse, which may be given in abundance. Other edible enrichments which were successful include things like corn-on-the-cob, non-sweetened cereals garlic, pumpkin, items from our browse garden, sugar cane, crab-apples, both fresh and dried figs, brown rice, onions, and popcorn, among other things. Frozen items like ice cubes and large blocks of ice (which float in the water) as well as frozen fruits and vegetables were all well liked, particularly in the Summer.

      Some enrichments which were not well received include rawhide bones and fresh herbs like sage, thyme, or rosemary; although the herbs and spices were unconsumed, the strong smells do pique the interest of the animals. Insects--such as wax worms, meal worms, crickets, and earthworms--and " Jello shots" when first introduced were met with mild interest. Unfavored edible enrichments can be used to offset preferred items, they may provide interactive behaviour even when not consumed and help to further break down the routine of an animal's day.

BROWSE

       In order to encourage primates to exhibit as healthy and natural a behaviour as possible, environ- mental stimuli such as fresh-cut browse should be used in abundance, if not daily. At CPWC, we have the advantage of collecting fresh-cut foliage from the zoo grounds as well as from our browse garden-- which is in its fourth harvest this year; the browse garden has successfully produced a variety of items, such as melon, snap peas, green beans, nasturtium, Swiss chard, thyme, sage, corn, sunflowers, and tomatoes, with new items tried each year.

      Branches without leaves are well received by the macaques and some other species, who strip the pieces of bark as they would in the wild; the stripped pieces can also be left in holding as additional cage furniture. Willow, for example, is plentiful and well liked as an edible item early in the season (Spring-Summer} when the leaves are young; as the Summer progresses, the willow is still useful for the monkeys to distract themselves with even if they are not consuming it.

       Edible browse lists from our facility as well as from others (the Bronx Zoo, the National Zoo, etc.) have been compiled for reference. Besides species like willow, forsythia, bamboo, and garden variety items, these reference lists which we utilize specify plants such as: nasturtium, banana plant, cattail, sunflower, maple, grapevine, euonymus, mulberry, beech, honeysuckle, crab tree, among several other species. The flowers, leaves, stalks, buds, or any part of these plants are offered, in tact, when avail- able, and generally consumed or utilized by the animals with eagerness.

      Although most of our browse is offered in the holding areas, on-exhibit browse is present to create a "blending of plants and animals" not only "reduces stresses associated with captivity, but it can promote natural behaviours..." Because of the impact and damage an animal can inflict on habitat plants, many species are considered and tried; in addition, large logs and branches are placed through-out the exhibit to help offset the erosion of living plants.

      Of course, not all of the plants available on our grounds are feedable. Some species are hazardous or toxic to the animals, like cherry, rhododendron, or nightshade; while other species are not fed out because they may not regenerate quickly or may not be plentiful enough for several animals. In addition, many of our plant species are nurtured strictly for aesthetic value, and the horticultural staff will have heads rolling if these plants are encroached upon!

      In addition to being cheap, edible, and abundant, browse also acts as a substrate material for animals to hide behind, drag around, or to bed down with.

SUBSTRATES AS ENVIRONMENTAL ENRICHMENT

      Substrates play an important role in enrichment programs just as much as edible items. Hay is used daily in the indoor holding areas to encourage foraging behaviour as well as for the animals to bed down with. Hay is used not only in the cold and damp weather, but all year round; it has also been used from time to time in the exhibit planters as well.

      On-exhibit substrates--such as sand, grass, pine bark chips and mulch, browse, and hay--are utilized and can usually be left in piles for the macaques to disperse themselves. However, with the implementation of the training program, we have decreased the use of enrichments out on exhibit in order to enhance the use of them within holding until further notice.

      Therefore, inside the holding area, we continue to offer large amounts of browse, burlap, bags and newspapers, and are trying other substrates--besides hay--as well. During the Fall when raked leaves are abundant, we have placed large piles of leaves in the cages which the macaques enjoy scattering and throwing around, chewing on and rolling in. Other suggestions which we have not tried but might be utilized with the macaques include feathers and fabric materials--like denim or terry cloth towels.

TOYS AND RECYCLABLE

      Besides new ideas for food and substrate enrichments, we are always on the look-out for toys and props for our animals to interact with.

       From the company Primate Products, we ordered some "primate puzzles" that came with nutrition- ally supplemented "candy." These puzzles consisted of coloured plastic pieces which could be fit in to the clear plastic framework to make a series of maze-like structures; once the candy-filled puzzles were attached to the cage fronts with cable ties, the monkeys could put their fingers through the slots from inside the holding cages and manoeuvre the treats--we use nuts or grapes--down to the larger slots to receive the rewards for their hard work. The company's instructions recommended that "showing your monkeys how to use the puzzle will result in successful retrieval of the Primate Products candy". We installed the puzzles on the cage fronts for use without previous introduction to the monkeys; although our young female Phoebe is usually the first to approach and try new things (similar to behaviour observed in 1950's field studies, in which a young female called Imo first washed her sweet potato in the ocean), in this instance our youngest male Scotty came right over and shook the cage front until all the candy pieces fell out. New York chutzpah at its best!

      Although this was not the "correct way of using the puzzle, I felt that Scotty demonstrated a lucid thought process of to how to get what he wanted in the quickest way possible; Scotty's shortcut did not catch on with the rest of the troop. Later that same afternoon, I witnessed several monkeys--including Scotty-manoeuvring and working the treats through the mazes and out through the slots for consumption. Although the primate puzzles proved to be a learning success, they were best used sporadically to prevent the macaques from becoming bored with the puzzles.

      Among other commercially-made toys that we have given to the macaques are boomer balls and large plastic spools; the recycled items that we have picked up from around the zoo include milk

crates, hard hats and plastic pails and trash cans. Some of these objects have holes cut in them and some without; all are of different colors and sizes and, over long-term use, have proven durable and still fun for the monkeys.

      Other recycled items that were well liked include paper bags, cardboard boxes and trash bag tubes, newspapers, phone books, and branches and perching with and without foliage. All these items come in different colors, shapes, and sizes; most of them are easily brought from home. And most important, cost-efficient items such as these go over very well with management as much as with the animals!

ACTIVITIES AND INTERACTION

      The macaque, whom we have already identified as a curious and gregarious species, spends much of its time in search of liveliness, utilizing all of its bodily senses; zoo keepers are often responsible for providing captive animals with much of the activities that promote liveliness and nurture the use of the body's senses. Therefore, besides the use of visual and tactile stimuli, we have tried to introduce variables which stimulate the olfactory and auditory senses among our monkeys.

       Both fresh and dried herbs and spices--garlic, lemon grass, rosemary, and cinnamon, among others-or store-bought perfumes can be sprinkled and doused on objects and in exhibits and holding areas. As with any new enrichment, these items provoke the animals to examine, explore, rub, and smell everything; the musky and fruity scents seemed to cause the most activity. Auditory stimulation has been encouraged, but not extensively, with a portable radio playing music or people talking; we have never tried pre-recorded vocalizations--of either macaques or other animals.

       In accordance with our training program protocols, we initially allowed the monkeys access to their enriched indoor holding area during zoo hours, thus conditioning them to the idea of coming in at any time besides the end of the day, as well as restoring trust with the keepers. By using verbal commands and tongs to distribute treats, we have been able to get most of the troop--with the exception of two monkeys out of ten-to sit or "target for a reward. We have been most successful with our younger monkeys and least successful with two of the older adults. Other troop members are middling.

      As an activity, positive reinforcement training and gating sessions provide intellectual stimulation for an animal, it breaks up the routine of the animal's day, and aids in decreasing stress and aggression, thus deterring stereotypic and abnormal behaviours--such as excessive grooming or fur-pulling.

CONCLUSION

      With any new enrichment introduced we must consider the durability, the expense, and the entertainment value, as well as any worst case scenarios and, of course, how practical it is to the zoo keeper. The use of environmental enrichments and positive reinforcement training techniques has fast gained a foothold in the wildlife industry. Positive reinforcement training offers the animal more control over its own life and the option to independently make its own choices; it gives the animal a chance to voluntarily work for its food; in addition, by performing "quantitative studies" of training, we can also offer an "objective way to evaluate the successes and failures of animal training efforts."

      At Central Park, we have implemented training and enrichment programs that are working well with several of our species besides the macaques--including colobus monkeys, pinnapeds, and polar bears. The macaques have proven challenging, but not so challenging as to discontinue working with them--to me, that alone spells success!