Gibbon Enrichment
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White-Handed Gibbon Enrichment

ENVIRONMENTAL ENRICHMENT RECOMMENDATIONS:

Provide: Feeding, Physical, Sensory and Social enrichment to encourage behaviours that are natural to wild gibbons.

PHYSICAL CHARACTERISTICS:

The White-handed gibbon (Scientific Name: PONGIDAE HYLOBATES Lar), like the gorilla, chimpanzee and orangutan, is an ape, not a monkey. The chief characteristics distinguishing apes from monkeys are the absence of a tail, their more or less upright posture and the high development of their brain. The White-handed gibbon (also know as the Lar gibbon) has a black to pale brown or yellowish-grey fur body, with white hair framing a black naked face. The palms of the hand and soles of the feet are also free of fur and white in color, hence its name. The animal's long arms and grasping hands with thumb, contribute to its ability to swing through the trees. Adult males weigh 10-20 lbs., females are slightly smaller. Dense fluffy fur keeps these animals cool in hot temperatures, and also presents a larger image to predators.

The tough, horny pads on their buttocks are fused to the hip bones and are indispensable to this animal that builds no nest. The pads provide some protection when the gibbon rests on bare tree limbs

DISTRIBUTION and HABITAT:

These arboreal primates are found in the forests of Southeast Asia and Sumatra , from lower Burma south through the Malay Peninsula and east throughout Thailand .

BEHAVIOUR:

In the wild, White-handed Gibbons spend about 35% of their day actively foraging for food, 24% in non-foraging activities (travel, play, sentry, aggression, mating, grooming or vocalizing) and 41% being inactive. White-handed gibbons brachiate, or swing by the arms, from branch to branch horizontally and vertically. Their long, strong arms enable them to quickly change direction in flight and to catch a handhold if they fall. White-handed gibbons live in peaceful family troops of 8-15 members, within a territory ranging in size from 30-100 acres. This territory is marked by a whooping, piercing "song," which broadcasts precise information on the species and sex of individuals, the area occupied by the adults and the presence of sub-adults ready to form a new pair. A different bark-like call is used to warm troop members of danger. With a keen sense of hearing and their agility in the trees, they are equipped to avoid the leopards, birds of prey and snakes that hunt them.

DIET:

White-handed gibbons live on leaves, buds and blossoms, tree ants and other insects, snails, small vertebrates, nestlings, and bird eggs. In the Zoo they are fed fruit, vegetables, monkey chow and water.

GALLERY OF ENRICHMENT

Exhibit Assessment

Feeding Enrichment-Feeder Bag

Feeding Enrichment-Feeder Ball

Feeding Enrichment-Browse Hanger

Feeding Enrichment-Feeder Bucket

Feeding Enrichment-Frozen Fruit Block

Feeding Enrichment-Feeder Mop

Feeding Enrichment-Stuffed Banana Stalk

Feeding Enrichment-Feeder Tube

Physical Enrichment-Hammock

Physical Enrichment-Mirror

Physical Enrichment-Poles

Physical Enrichment-Ropes

Physical Enrichment-Water

Sensory Enrichment-Christmas

Sensory Enrichment-Novel Foods

Social Enrichment-Training

Annual Exam

 

 

Exhibit Assessment:

In the original design of the Gibbon exhibit the principle consideration was to accommodate the gibbon’s arboreal nature.  The pole structure was designed by Zookeepers and constructed over 15 years ago. In recent years with more consideration being given to environmental enrichment, modular changeable features have been added: a hammock, ropes, occupational feeder device and toys. These additions provide a changing non-stationary environment offering challenges that their wild counterparts might have to face: search for food, novel encounters, and a change in brachiating patterns. The gibbons’ behaviours were studied in their basic exhibit structure and compared to those of their wild counterparts.

Wild Gibbons -Foraging: 35%
Wild Gibbons -Non-Foraging: 24%
Wild Gibbons -Inactive: 41%
Our Gibbons -Foraging: 32%
Our Gibbons -Non-Foraging: 52%
Our Gibbons -Inactive: 16%

These findings show that our gibbons’ activity levels are equivalent to those of their wild counterparts in foraging and greatly more active in non-foraging. This could be because of  the increased energy level of our two juveniles and/or the constant proximity and encouragement of the visiting public.

Thanks to contributions from the Wildest Show in Town of 2001, the Honolulu Zoo Society has designated over $7,000 for Primate Island Improvements. In meetings of management and the primate keeper, plans have been made that include: changing to a naturalistic looking exhibit by the addition of a large tree, increasing the total area, providing shaded areas, more modular  and non-static features, improving the night quarters and increasing the size to accommodate enrichment and training.  

Our goals in the gibbons’ Environmental Enrichment Program are to provide a changing environment, increase foraging and play, establish routine gating and decrease stress due to human interaction at times of physical examinations.

 

 

Feeding Enrichment-Feeder Bag:

 

Enrichment Type: Feeding-presentation.
Target Behaviour: “Working” for food, exploration and play
Set-up: 1" nylon net bags filled with food items hung on exhibit.
Data Collection: Scan sampling results of 4 hour block observations with an average of the 1st, 5th,10th presentation of activity, given never less than three weeks apart.
Conclusions: All gibbons went immediately to investigate. The juveniles showed the most enthusiasm for the exhibit addition. The adult male went into his usual sentry position high on exhibit, while the mother did her usual sunning. All would periodically return to the feeder bags for further investigation. Mycah would antagonize dad into playing while baby Emma amused herself with the bags. Males had renewed interest in the bag when Emma would extrude large browse pieces from the bag. At two hours when enough leaves had been removed from the bag to expose the core of treats, all gibbons returned to foraging the bags. By three hours all the contents of the bags had been foraged and the fall out items had been foraged from the ground.

 

Without Enrichment -Foraging:                   32%      
With Enrichment -Foraging:                         46  %
Without Enrichment -Non-Foraging:          52%      
With Enrichment - Non-Foraging:               32 %
Without Enrichment -Inactive:                     16 %
With Enrichment -Inactive:                           21 %

 

Scheduling Recommendations: Twice a month, on or off exhibit.

 

 

Feeding Enrichment - Feeder Ball:

 

Enrichment Type: Feeding-presentation 

Target Behaviour: “Working” for food, exploration and play

Set-up: 12” plastic ball with ½” holes filled with dry treats hung on exhibit

Data Collection: Scan sampling results of 4 hour block observations with an average of the 1st, 5th,10th presentation of activity, given never less than three weeks apart 

Conclusions: All gibbons showed interest in this activity.  The mother had the most persistence, poking her fingers/thumb in the lower holes and was able to jiggle out treats that dropped to the ground where she retrieved them. The others noticed that the treats were falling to the ground and would wait on the ground to pick them up. The mother later became more adept at jiggling and poking and was able to catch the treats in her hand as they fell out. This activity maintained their interest beyond the first day and they were still retrieving treats the second day. The ball also proved to be a fascination for playing and swinging, so it is left empty on exhibit for up to a week. This activity greatly increased the overall activity level of the exhibit.

 

Without Enrichment -Foraging:            32%       

With Enrichment -Foraging:                  66%

Without Enrichment -Non-Foraging:   52%

With Enrichment - Non-Foraging:        25%

Without Enrichment -Inactive:              16 %      

With Enrichment -Inactive:                    9%

 

Scheduling Recommendations: Twice a month, on or off exhibit. Can be left on exhibit as a play item for several days.

 

 

Feeding Enrichment - Browse Hanger:

 

Enrichment Type: Feeding-presentation 

Target Behaviour: “Working” for food, exploration and play 

Set-up: A Zigzag weave of fire hose tucked with browse hung on exhibit

Data Collection: Scan sampling results of 4 hour block observations with an average of the 1st, 5th,10th presentation of activity, given never less than three weeks apart.

Conclusions: All gibbons showed interest in this activity. The males would approach it first with interest in pulling out the branches and “killing” the object, only later would they show any interest in eating any of the browse. The females took a more delicate approach to the hanger, taking deliberate interest in selecting which browse pieces to pick off to eat. The juveniles found such delight in leaping on and off the hanger, even after all the browse and food items were gone, that the browse hanger was left on exhibit for months at a time, and weekly replenished with new browse. There was a vigorous increase in vocalization on the days of browse presentation.

 

Without Enrichment -Foraging:           32%       

With Enrichment -Foraging:                 50%

Without Enrichment -Non-Foraging:  52%       

With Enrichment - Non-Foraging:       31%  

Without Enrichment -Inactive:             16%      

With Enrichment -Inactive:                   19%

 

Scheduling Recommendations:  Hanger can be left on exhibit for months as a play item with fresh browse added weekly.

 

 

Feeding Enrichment-Feeder Bucket:

Enrichment Type: Feeding-presentation 

Target Behaviour: “Working” for food, exploration and play

Set-up: A 5gal. Bucket with four baffled compartments and rotating lid with 2 ½” hole filled with fruits and vegetables hung on exhibit 

Data Collection: Scan sampling results of 4 hour block observations with an average of the 1st, 5th,10th presentation of activity, given never less than three weeks apart

Conclusions: All gibbons went immediately to investigate. The juveniles were the first to investigate, but it was mom who dominated this activity, pulling out the contents and dropping the items that she didn’t want. There was no need for everyone to stick their hand in the bucket with mom so willing to toss out all the treats! There was always someone investigating the bucket touching or looking into the bucket before sticking their hands in, getting bolder as the day wore on. After all the observations the twirling of the lid and revealing of new compartments still appeared to be “trail and error” The revealing of new compartments caused great excitement with mom starting the whole foraging routine over again. This enrichment was in use continuously for the first 3.5 hrs; all animals took a turn. The juvenile male liked picking up the bucket by the rope, biting the rope and even manoeuvred the bucket handle above the bucket, held onto an upper bar with his feet and used his hands to heft the bucket. The juveniles batted and kicked at the bucket in play more than the adults.

 

Without Enrichment -Foraging:           32%       

With Enrichment -Foraging:                 44%

Without Enrichment -Non-Foraging:  52%       

With Enrichment - Non-Foraging:       46%

Without Enrichment -Inactive:             16%      

With Enrichment -Inactive:                   10%

 

Scheduling Recommendations: Twice a month, on or off exhibit.

 

Feeding Enrichment-Frozen Fruit Block:

Enrichment Type: Feeding-presentation and Sensory-frozen tactile.

Target Behaviour: “Working” for food, exploration and play.

Set-up: A 1gal. Juice bucket filled with fruit and a hanging rope frozen and hung on exhibit.

Data Collection: Scan sampling results of 4 hour block observations with an average of the 1st, 5th,10th presentation of activity, given never less than three weeks apart.

Conclusions: All gibbons showed interest in this activity. The juveniles showed the most interest, licking and picking at the exposed fruit, occasionally shaking their head and hands as though in reaction to the cold. The adults investigated the block but seemed to wait until the fruit pieces became exposed by melting. As the hanging rope became exposed, there was increased interest in the block with the gibbons using the rope to manipulate the block to work out the choicest fruit pieces and using the rope for play and acrobatics. This activity greatly increased the overall activity level of the exhibit.

 

Without Enrichment -Foraging:             32%

With Enrichment -Foraging:                   68%

Without Enrichment -Non-Foraging:    52%       

With Enrichment - Non-Foraging:         21%

Without Enrichment -Inactive:               16%      

With Enrichment -Inactive:                     11%

 

Scheduling Recommendations: Twice a month, on or off exhibit. Best on hotter days.

 

 

Feeding Enrichment-Feeder Mop:

  

Enrichment Type: Feeding-presentation 

Target Behaviour: “Working” for food, exploration and play 

Set-up: A clean cotton mop with each strand strung with fruit loops hung on exhibit

Data Collection: Scan sampling results of 4 hour block observations with an average of the 1st, 5th,10th presentation of activity, given never less than three weeks apart

Conclusions: All gibbons showed interest in this activity. The males would make an initial attack on the mop, but it was always the mother who methodically picked off the fruit loops from each string, often joined by the juveniles. The father would pick up loops that dropped to the ground. The feeding would typically last but a short time in comparison to the time it takes to string them on (Education Zoo Adventure kids come in handy for this!). After feeding was complete it was the juveniles that monopolized the mop, using it to swing from in several positions; upside down, head in mop, one-handed, sitting on it, biting it, wrestling with it, making the mop swing by itself, swinging away from it with wild leaps and flailing arms and legs, posturing as with a flag. The mop was left on exhibit for play for several days.

 

Without Enrichment -Foraging:           32%

With Enrichment -Foraging:                 35%

Without Enrichment -Non-Foraging:  52%

With Enrichment - Non-Foraging:       32%

Without Enrichment -Inactive:             16%

With Enrichment -Inactive:                   33%

 

Scheduling Recommendations: Twice a month, on or off exhibit. Can be left on exhibit as a play item for several days.

 

 

Feeding Enrichment - Stuffed Banana Stalk:

  

Enrichment Type: Feeding-presentation. 

Target Behaviour: “Working” for food, exploration and play. 

Set-up: A Banana tree plugged with holes filled with food  placed on exhibit. 

Data Collection: Scan sampling results of 4 hour block observations with an average of the 1st, 5th,10th presentation of activity, given never less than three weeks apart.

Conclusions: All gibbons showed interest in this activity. The boys would make straight for the leaves tearing large leaves from the stalk and swing off with them holding them in their feet and tearing off pieces of the leaf to eat. The girls quickly discovered that there were goodies in the stalk and used both their teeth and hands to pick out the items. The juveniles’ attention turned into rambunctious playing in the leaves, pulling them down, sliding down the stalk, grabbing pieces of leaves and swinging away with them. The duration of foraging time increased when pasty food items were used in the holes. This activity greatly increased the overall activity level of the exhibit, and was very popular with the public, although the exhibit did get a trashed appearance by the end of the day.

 

Without Enrichment -Foraging:           32%       

With Enrichment -Foraging:                 53%