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% |
|
Without
Enrichment -Non-Foraging: 52% |
|
With
Enrichment - Non-Foraging:
36% |
|
Without Enrichment -Inactive:
16% |
|
With Enrichment -Inactive:
11% |
| Scheduling
Recommendations: Twice
a month, on or off exhibit. Plan for a major exhibit cleanup afterwards. |
|
Enrichment Type:
Feeding-presentation. |
|
Target Behaviour:
“Working” for food, exploration
and play. |
|
Set-up: A
2 ½” PVC capped pipe with ½” slit along
side filled with fruits and vegetables hung on exhibit. This is a reusable
variation on a cardboard tube filled with food, which is occasionally still
used. (Our exhibit is surrounded by a moat, play items and feeders that are
not roped to the exhibit end up in the pool!). |
|
Data Collection:
Scan sampling results of 4 hour block observations |
|
Conclusions:
It was the mother of our family group that showed the most systematic
determination in extruding food items from the tube, sitting for long
periods of time working at the tube. The juveniles in constant play would
stop and show interest in mom’s activity as she successfully extruded
large pieces of food, which they would steal away with! Foraging duration
can be lengthened by use of frozen food items in the tube. |
|
Without
Enrichment -Foraging: 32% |
|
With
Enrichment -Foraging:
38% |
|
Without
Enrichment -Non-Foraging: 52% |
|
With
Enrichment - Non-Foraging:
36% |
|
Without Enrichment -Inactive:
16% |
|
With Enrichment -Inactive:
26% |
| Scheduling
Recommendations: Twice
a month, on or off exhibit. Can be left on exhibit as a play item for
several days. |
|
Enrichment Type:
Physical-Structural |
|
Target Behaviour:
Exploration and play. |
|
Set-up: Triangular
hammock hung on
exhibit. |
|
Data Collection: Accumulation
of |
|
Conclusions:
A six-foot triangular fire hose hammock was hung on exhibit. The adults were
the first to explore the new hammock. The hammock appeared to increase the
activity of all the gibbons that moved constantly back to and around the
hammock. Its position did not
appear to hamper the gibbons’ brachiation. They also took advantage of its
shade to rest occasionally on one of the poles under it (an unusual
resting-place for them). While
it seemed that the parents would have liked to use the hammock to rest, the
kids were in constant motion in and around it, running along the edge,
swinging from it, jumping from all sides down into the hammock and taking
flying leaps into it so that the adults repeatedly had to move out and leave
the hammock to the kids. All the gibbons appeared to be interested in the
nuts and bolts clamping the underside of the hammock, and M several times
seemed to be trying to undo the rope attached to the hammock chain. |
| Scheduling
Recommendations:
Relocation of hammock seasonally |
|
Enrichment Type:
Sensory-visual, Feeding-presentation. |
|
Target Behaviour:
“Working” for food, exploration
and play. |
|
Set-up:
1 foot square mirrored box |
|
Data Collection: Accumulation
of daily
observations during normal species interaction and maintenance by the keeper
and volunteers. |
|
Conclusions:
The gibbons showed little to no interest in their reflection in the mirror.
The juvenile male was startled at first then became indifferent. The best
use of the mirrored box was as a feeder device, hung on the outside of the
1” mesh fencing of their inside quarters and filled with food. The mother
spent the most time picking the food through the mesh, preferring this
foraging activity even when the same food was also available in an open pan
within arm’s reach. This mirrored box was rotated monthly to other primate
quarters with greatly varying behaviours. Our Langurs were fascinated with
their reflection, the alpha male
producing a territorial clicking sound that he makes at no other time. Our
Siamang females became defensive as to who got the use of the mirror. Our
female Patas would spend hours staring at herself almost hypnotizing
herself. |
|
Scheduling
Recommendations:
Remove or reintroduce mirror monthly. |
|
Enrichment Type:
Physical-Structural. |
|
Target Behaviour:
Exploration and play. |
|
Set-up:
Existing exhibit structure. |
|
Data Collection: Accumulation
of daily
observations during normal species interaction and maintenance by the keeper
and volunteers. |
|
Conclusions:
The gibbons make excellent use of the current pole structure, utilizing
every available segment. All poles are of the same 4”diameter so no
comparison of diameter preference can be made. The horizontal spacing is
4’ and allows for easy ascension to the next level from a position of
rest. The horizontal spacing of 8’ allows for acceleration and ‘air time' of
brachiation. There
has been no use of diagonal poles, non-stationary poles or natural branches
at this point for observations, but a current new exhibit is being planned
to include a large tree, and non-static features. |
| Scheduling
Recommendations:
Unalterable. |
|
Enrichment Type:
Physical-Structural |
|
Target Behaviour:
Exploration and play. |
|
Set-up:
Existing exhibit |
|
Data Collection: Accumulation
of daily
observations during normal species interaction and maintenance by the keeper
and volunteers. |
|
Conclusions:
The
addition of ropes to the exhibit increased the overall activity level by
increasing the exhibit’s useable space. A noticeable change in the
brachiating patterns is observed when the ropes are seasonally moved about
on exhibit. There is very little difference in use of nylon rope vs. manila
rope, although the nylon is more durable, and less likely to be ingested.
However the ends need to be seared to avoid fraying. The smaller diameter
ropes (½ ”and ¾”) are used less then the larger ones (1” and 1 ½”).
Fire hose ropes are used more often for sitting on than the round
ropes, with no difference in their use for brachiating. The addition of a
taut rope over the bridge increased water play and the juvenile male has
been on occasion seen tightrope walking along it. The vertical spacing of
ropes and poles is best at about 3 feet to 4 feet and the horizontal spacing
appears best at about 6 feet to 8 feet. |
| Scheduling
Recommendations:
Addition or relocation of ropes seasonally. |
|
Enrichment Type:
Sensory- Tactile |
|
Target Behaviour:
Exploration and play. |
|
Set-up: Existing
exhibit |
|
Data Collection: Accumulation
of daily
observations during normal species interaction and maintenance by the keeper
and volunteers. |
|
Conclusions:
Primates might indeed have a fear of deep water, but they spend a lot of
time interacting with it from the bank and from the plank: playing with
items that float near their island, using leaves and even bottle caps as
cups to drink from, or just a cupped hand drinking the water that rolls off
the fingers. The juveniles interact with the water more than the parents and
the mother more than the father does. They dislike being wet, avoid the
rain, and generally go out from the inside quarters when keepers are hosing.
The island has a licks-it that the gibbons use as frequently as drinking out
of the pool. The inside quarters have large rabbit- type water bottles, but
the gibbons don’t usually use them unless they have no access to the
exhibit or unless the bottles are filled with juice. The adults are adept at
drinking from a squeeze bottle, which is used to reinforce an open mouth
exam behaviour. |
| Scheduling
Recommendations:
Unalterable. |
|
Enrichment Type:
Sensory |
|
Target Behaviour:
Exploration and play. |
|
Set-up:
Stockings and presents on exhibit
with treats and toys. |
|
Data Collection: Accumulation
of yearly
observations during normal species interaction and maintenance by the keeper
and volunteers. |
|
Conclusions:
Over the years the gibbons have come to know what these colourful packages
and stockings hold, and are as excited as any child would be. This is also a
great community event. Volunteers donate items and enjoy stuffing stockings
and wrapping presents. The media is notified, and the general public comes
to watch. This can often detract from that special moment of the season that
the keepers share with their family of animals, so usually the keepers and
animals also have a private behind the scenes Christmas. Gibbon birthdays
are also celebrated with special treats and presents. |
|
Scheduling
Recommendations:
Seasonally |
|
Enrichment Type:
Sensory- Taste |
|
Target Behaviour:
|
|
Set-up:
Seasonal fruits or treats |
|
Data Collection: Accumulation
of daily
observations during normal species interaction and maintenance by the keeper
and volunteers. |
|
Conclusions:
The excitement of novel foods heightens the animals’ interest and focus on
the keeper’s presents.
 |
Seasonally
grown favourites are: mangos, pineapples, figs,
Madagascar
olives, tamarinds, false kamani nuts, hala fruit,
melon, kiwi, monkeypod pods, tomatoes, corn on the stalk, and
Surinam
cherries. |
|
Occasional
treats (less then once a month) are: primate brownies and laulaus,
pasta, Jell-O, popcorn, peppermint candy, hard-boiled eggs, and breads. |
|
Regular
treats (used in association with training) are raisins, peanuts and
cereal. |
|
|
Scheduling
Recommendations:
Weekly offering of a non-regular diet item. |
|
Enrichment Type:
Social- Training |
|
Target Behaviour:
Gating, Stationing, Exam
behaviour, Cooperative feeding |
|
Set-up:
Physical interaction stations |
|
Goals:
Train all individuals to respond to a
clicker, station at a target, take food by hand and remain calm while other
activities go on around them. |
|
Applications:
Group may be called off exhibit and gated. Individuals may be stationed and
cage shifted for examination behaviour training. |
|
SHAPING
PLAN
|
Level
1 - Establish response
with animals individually and together. |
|
Level
2 - Work in the inside
quarters away from exhibit door. |
|
Level
3 - Give a positive
small item motivator (i.e. raisins or peanuts with primates) |
|
Level
4 - Reward progressive
movement toward the target or trainer. |
|
Level
5 - Click / reward
each desired behaviour (i.e. hand feeding stationing behaviour). |
|
Level
6 - Time out when any
individuals show aggression. |
|
Level
7 -
Increase duration of session. |
|
Level
8 - Repeat session
several times during the day. |
|
Level
9 - Progressively move
stationing area further from the exhibit door. |
|
Level
10 - Begin desensitization of trainer's movement toward door. |
|
Level
11 - Reinforce as you touch and rattle the door. (gating behaviour) |
|
Level
12 - When possible, close door, give bonus, and open immediately. |
|
Level
13 - Slowly extend period of time door is closed. |
|
Level
14 - Reward with BIG bonus upon sending animals out of quarters. |
|
Level
15 - Work dominant individuals into the far quarters, close door, and
station with bonus. |
|
Level
16 - Work with less dominant individuals while dominants are closed off. |
|
Level
17 - Slowly work to cooperatively feed entire group (see cooperative
feeding protocol ) |
|
Level
18 - Work with isolated individuals on exam behaviours( see exam behaviour
protocol ) |
|
|
Note:
The key to clicker training is to click at the exact instant the positive
stimulus occurs, And the key to desensitization is to bridge the exact
instant the negative stimulus occurs |
|
Scheduling
Recommendations:
Daily |
The Gibbons as well as the
other primates at the Honolulu Zoo
are observed
on a daily basis by their Keepers
for any physical changes or
illnesses through a training of presenting
body parts for exam. Annually
it is necessary for the Vet staff
to conduct a thorough health exam.
The animals are immobilized, weighed,
vital signs of heart and respiration rate are recorded, samples of blood and
stool are collected for testing, vaccinations are given, oral, eye and external
exams are conducted, and a TB test is given. At any signs of concern a more
in-depth procedure may be conducted. Our alpha male a year ago after the birth
of a daughter and having sired two males and a female, ensuring his genetics,
was neutered at the request of the Species Survival Plan. The juveniles have
both been implanted with micro identification chips. This year our mother gibbon
was implanted with birth control. Although the gibbons are the only monogamous
primate, and although her mate is
now fixed, and our juvenile male at 3 ½ years old is years away from
becoming a viable breeder, it was decided to play on the side of caution and
implant her. |
