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
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.
| 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. |
|
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. |
|
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. |
|
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. |
|
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. |
|
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. |
|
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% |
|
|
