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We studied the daily time budget and feeding activity of the bear cuscus, Ailurops ursinus, in the Tangkoko-Duasudara Nature Reserve, North Sulawesi, Indonesia. Bear cuscuses spent 63.4% of their time resting, and feeding accounted for only 5.6% of their activity. Bear cuscuses fed on 31 species of plants, including 26 identified trees and lianas from 17 families and 5 unidentified mistletoes. Dietary preference was influenced by availability of young leaves, and bear cuscuses maximized the amount of young leaves in the diet.
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American Society of Mammalogists
Diet and Activity of the Bear Cuscus, Ailurops ursinus, in North Sulawesi, Indonesia
Author(s): Asri A. Dwiyahreni, Margaret F. Kinnaird, Timothy G. O'Brien, Jatna Supriatna,
Noviar Andayani
Journal of Mammalogy,
Vol. 80, No. 3 (Aug., 1999), pp. 905-912
Published by: American Society of Mammalogists
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Journal of Mammalogy.
Wildlife Conservation Society-Indonesia Program, Post Office Box 311,
Bogor 16003, Indonesia (AAD, MFK, TGO)
Department of Biology, Faculty of Mathematics and Sciences, University of Indonesia,
Depok 16424, Indonesia (JS, NA)
We studied the daily time budget and feeding activity of the bear cuscus, Ailurops ursinus,
in the Tangkoko-Duasudara Nature Reserve, North Sulawesi, Indonesia. Bear cuscuses
spent 63.4% of their time resting, and feeding accounted for only 5.6% of their activity.
Bear cuscuses fed on 31 species of plants, including 26 identified trees and lianas from 17
families and 5 unidentified mistletoes. Dietary preference was influenced by availability of
young leaves, and bear cuscuses maximized the amount of young leaves in the diet.
Key words: Ailurops ursinus, bear cuscus, Garuga floribunda, Sulawesi, time budget,
diet, feeding preferences
The marsupial family Phalangeridae is a
monophyletic group that includes ->17 liv-
ing species, all of which are partly or whol-
ly arboreal omnivores or herbivores (Flan-
nery et al., 1987). The Phalangeridae has
the most extensive range of any Austral-
asian family of marsupials and occurs in
Australia, Tasmania, Papua New Guinea,
and throughout islands east of Wallace's
Line as far as the Solomon Islands (George,
1987). The Indonesian island of Sulawesi
forms the northwestern limit of its distri-
bution (Flannery et al., 1987; George,
1987). Although known to European zool-
ogists as early as the 18th century, the Phal-
angeridae remains poorly known, especially
its ecology, with the possible exception of
the Australian brush-tailed possum, Tricho-
surus vulpecula, and the Australian moun-
tain possum, T. caninus (Flannery et al.,
The bear cuscus, Ailurops ursinus, is the
largest and most primitive species of the
Phalangeridae, and it is found only on Su-
lawesi and surrounding islands. The bear
cuscus lives in sympatry with the dwarf
cuscus, Strigocuscus celebensis, except on
Peleng Island in Central Sulawesi, where it
is sympatric with the Peleng Island cuscus,
S. pelengensis, an endemic species (Flan-
nery, 1995). The bear cuscus is an arboreal
folivore that lives in the upper canopy of
lowland forest. It is active during the day
and found mostly in pairs (Tarmudji and
MacKinnon, 1980). Unlike the bear cuscus,
both species of Strigocuscus are predomi-
nantly nocturnal and frugivorous.
There is no detailed information on the
ecology of the bear cuscus on Sulawesi, es-
pecially its feeding habits (George, 1987).
The only previous study was a survey con-
ducted by Tarmudji and MacKinnon (1980)
that provided general information about be-
havior. Detailed information is needed to
enhance conservation of this little-known
marsupial. O'Brien and Kinnaird (1996) re-
ported that the population of bear cuscuses
in the Tangkoko-Duasudara Nature Reserve
on Sulawesi decreased 95% over 15 years
as a result of hunting pressure. We describe
daily activity patterns of the bear cuscus,
focusing on feeding behavior, and provide
the first preliminary data on its dietary di-
versity and preference.
Journal of Mammalogy, 80(3):905-912, 1999 905
Study area.-We conducted our study in
April-July 1995 in Tangkoko-Duasudara Nature
Reserve. The 8,867-ha reserve lies on the north-
ernmost tip of Sulawesi (1'30'-1o34'N, 125081'-
125010'E) and contains many habitats, including
beach forest, lowland forest, montane forest, and
even moss forest on peaks of Mount Tangkoko
and Mount Duasudara. Annual rainfall varied
from ca. 1,500 to 2,400 mm and was distributed
in distinct wet (October-April) and dry seasons
(May-September). We worked within a 416-ha
area of lowland forest, located on the north
slopes of Mount Tangkoko. The area was grid-
ded by trails forming 1-ha blocks. Canopy with-
in the area was dominated by five species of
trees: Palaquium amboinense (Sapotaceae),
Cananga odorata (Annonaceae), Homalium ce-
lebicum (Flacourtiaceae), Dendrocnide micro-
stigma (Urticaceae), and Eugenia (Myrtaceae).
Collection of data.-To collect behavioral
data, an individual or a group of bear cuscus was
located within the study area between 0600 and
0900 h and followed until 1700 h. Data collected
included height of a bear cuscus in the tree, spe-
cies of tree, and behavioral data. Behavioral data
were collected using focal-animal sampling (Alt-
mann, 1974) at 30-s intervals during 10-min
sampling periods followed by 5 min of no ob-
servation. Whenever possible, the focal animal
was selected according to a fixed rotation among
individuals in a group.
Animals were categorized into four classes of
age and sex. Adult males were identified by their
large size and prominent genitalia. Adult fe-
males were identified by large size and being
paired with an adult male, or large size and pres-
ence of an independent juvenile, or presence of
a clinging infant. Subadults were smaller than
adults and usually still living in a group with
adults; infants were smaller than subadults and
generally still carried by an adult female.
Behavior was classified into five activities.
Resting was defined as a behavior during which
no locomotion occured, regardless of posture;
sleeping, sitting still, and sitting with slight
movement of head, tail, hand, or leg were in-
cluded in that category. Moving was defined as
walking or moving the whole body to change
position, and feeding was defined as taking food
into mouth, biting, chewing, and swallowing;
sniffing and investigating food on branches were
included in this category. When the focal animal
was feeding, the plant species and part of the
plant that was eaten were recorded. Grooming
was defined as picking, scratching, or removing
debris from an individual's own fur, and social
activity was defined as grooming others, nurs-
ing, or being nursed.
Leafing phenologies were studied along a
transect (5 m by 2,500 m), twice each month, to
assess availability of food. We used a score of
0-4 for each tree (Struhsaker, 1975), in which 0
indicated no leaves; 1, 1-25% coverage; 2, 26-
50% coverage; 3, 51-75% coverage; 4, 76-
100% coverage of leaf buds, young leaves, and
mature leaves.
Analysis of data.-We calculated average per-
centage of records spent in the five behavioral
categories for each individual bear cuscus for 3
periods: morning (0600-1100 h), mid-day
(1101-1400 h), and afternoon (1401-1700 h).
We summed the average value for each individ-
ual and calculated an overall mean percentage
of records for each behavior by time of day, and
then calculated the overall mean percentage of
each behavior for bear cuscuses in general. We
used analysis of variance and Duncan's multi-
ple-range tests (Sokal and Rohlf, 1981) to ex-
amine the influence of time of day, age, and sex
on each behavior. Because data were propor-
tions, we applied an arcsine-square-root trans-
formation before analysis.
For feeding activity, we calculated the aver-
age proportion of records for eating a particular
species of plant and items (leaf, flower, or fruit)
for each bear cuscus. We then summed the av-
erage value for all individuals and calculated an
overall mean percentage of activity spent feed-
ing on each species of plant and item.
We calculated a biweekly phenological index
using the midpoint of the range of percentages
for each phenological score (Kinnaird, 1992)
and considered this a measure of the availability
of leaves as dietary items. We used Jacob's in-
dex of preference (Jacob, 1974) to rank feeding
preference by bear cuscuses. Jacob's index (D)
compared the frequency of each species being
eaten to its availability in the environment. D-
values range from -1 to + 1; as the index ap-
proached +1, it indicated increasing preference,
and as index approached -1, it indicated strong
To determine the effect of availability of
leaves on feeding preferences and the proportion
of activity spent feeding by bear cuscuses, we
August 1999 DWIYAHRENI
used multiple regression analysis (Sokal and
Rohlf, 1981). For the analysis, we used the bi-
weekly availability of leaf buds, young leaves,
mature leaves for each dietary species and the
week of study as independent
preferences and proportion of activity spent
feeding by bear cuscuses were dependent
ables. The partial slope (P3)
of each independent
variable was evaluated using type-III sums of
square, and all analysis were performed
the Statistical Analysis System (SAS Institute
Inc., 1985).
We collected 32,823 behavioral obser-
vations during 1,643 10-min sampling pe-
riods on individual cuscuses. Although bear
cuscuses were not individually identifiable,
those found in about the same location with
the same group composition were consid-
ered the same individual. Fifty bear cuscus-
es were found in pairs, 33 were in groups
of three or four individuals, and 17 were
solitary. We found bear cuscuses in 29 spe-
cies of tree, at an average height of 20 m
? 2.66 SD.
Daily activities.--Bear cuscuses spent
most of the time resting and sleeping (Fig.
la). Resting declined from morning to af-
ternoon, although not significantly, while
feeding showed opposite trends that were
significant. Feeding comprised only 5.6%
of the activity budget of the bear cuscus,
and proportion of activity spent eating was
significantly greater in the afternoon than in
the morning (F = 3.2; d.f. = 2.243; P =
0.04). Moving accounted for 23% of the
time budget. Movements declined from
morning to afternoon, but the difference
was not significant. Grooming accounted
for 7.5% of the daily activity budget, and
the bear cuscus spent only 0.4% of its ac-
tivity in social behavior. There were no sig-
nificant differences in the distribution of be-
haviors among classes of age and sex (Fig.
Dietary items.-Bear cuscuses fed on 31
species of plants, including 26 identified
trees and lianas from 17 families and 5 un-
identified mistletoes. However, >50% of
70 C3Morning EMid-day OAfternoon
S 5so
o 40
S 20
0 Resting Moving Feeding Social Grooming
70 - Resting OMoving EFeeding ~ISocial EGrooming
F 50
o 40
m 30
C 20
S 10
0 Male Female Sub adult Juvenile
Age-Sex Class
1.-Percentage of activity spent by bear
cuscuses in five behavioral
to a) time of day and b) age-sex class.
their diet comprised only three species of
tree: Garuga floribunda (23.5%), Melia
azedarach (19.4%), and Dracontomelum
dao (17.9%, Table 1). They fed mainly on
young leaves (54.4% of their diet), fol-
lowed by mature leaves (22.9%), and leaf
buds (7.8%; Table 1). For some species,
such as mistletoes, Cananga odorata and
Palaquium amboinense, bear cuscuses
chose mature leaves over young leaves.
Bear cuscuses ate petioles (leaf stalk) of
some species, especially when leaves were
mature. We once observed a bear cuscus
removing the blade of mature leaves of C.
odorata before eating petioles, and leaves
of Pterocymbium javanicum with eaten pet-
ioles were found under a tree used by a bear
cuscus for sleeping. Fruit was a minor part
of the diet, and unripe fruits were eaten
more than ripe fruits (unripe, 4.2%; ripe,
0.4%). Bear cuscuses also occasionally fed
on flowers and flower buds (2.9%). The re-
1.-Species and part of plants eaten by bear cuscuses during the sampling periods as a
percentage of activity budget spent feeding, based on 2,653 feeding records.
Family Speciesa nb Bud Young Mature Otherc Total
Anacardiaceae Dracontomelum dao 475 3.7 12 0.1 2.1 17.9
Koodersiodendron pinnatum 25 0.2 0.6 0.1 0.9
Annonaceae Cananga odorata 26 0.3 0.4 0.3 1
Alstonia ranvolfia 19 0.7 0.7
Urceola 47 1.8 1.8
Asclepiadaceae Marsdenia 5 0.1 0.1 0.2
Burceraceae Garuga floribunda 624 2.7 14.8 3.9 2.1 23.5
Ebenaceae Diospyros rumpii 3 0.1 0.1
Euphorbiaceae Macaranga tannarius 72 2.7 2.7
Fabaceae Derris elliptica 15 0.1 0.5 0.6
Flacourtiaceae Homalium celebicum 61 2.3 2.3
Meliaceae Melia azedarach 514 0.1 10.1 8.1 1.1 19.4
Moraceae Artocarpus dadah 16 0.5 0.1 0.6
Ficus variegata 55 0.8 1.3 2.1
Myrtaceae Eugenia 3 0.1 0.1
Syzygium 68 2.3 0.2 0.1 2.6
Sapotaceae Palaquium amboinense 206 0.1 0.8 3.5 3.4 7.8
Sterculiaceae Pterospermum javanicum 15 0.3 0.3 0.6
Verbenaceae Vitex quinata 136 0.1 4.2 0.2 0.6 5.1
Mistletoe A 100 0.2 0.9 2.5 0.2 3.8
Mistletoe B 82 0.1 0.1 2.8 0.1 3.1
Total 2567d 7.8 54.4 22.9 11.8 96.9d
a Four species of plants-Dracontomelum mangiferum (Anacardiaceae; young leaves), Alstonia sumatrana (Apocynaceae; young
and mature leaves), Ficus (Moraceae; unripe fruits), and Pterocymbium javanicum (Sterculiaceae; young leaves and petioles)-
were eaten outside the sampling periods and not included in the percentage of time spent feeding.
The number of feeding records in which a species was eaten by bear cuscuses.
c Other category consists of flowers and fruits and unidentified parts for listed species.
The remaining 86 observations (3.1%) of the diet, consisted of unidentified parts, flowers and fruits, and leaves of four plants
species (Aglaia and species of mistletoe) that each comprised <0.1% of the diets.
maining 7.4% of the diet comprised un-
known parts of plants and four species of
plants (Aglaia and species of mistletoe) that
each comprised <0.1% of the diets.
Feeding preferences.-Although the val-
ues of Jacob's index do not indicate a pref-
erence for any species in the diet, the values
do indicate the ranking of dietary prefer-
ence. G. floribunda was the most preferred
species in the diet (D = 0.021), followed
by D. dao (D = -0.230) and M. azedarach
(D = -0.237; Table 2). Among all dietary
species, multiple regression analysis
showed that Jacob's index was influenced
only by biweekly availability of young
leaves (partial P = 0.03, t = 2.91, P =
0.004). Similarly, multiple regression anal-
ysis indicated that availability of young
leaves also influenced the percentage of ac-
tivity spent eating each species (partial P =
0.004, t = 2.67, P = 0.009). Although
availability of young leaves across all spe-
cies stayed relatively constant throughout
the study (Fig. 2a), it fluctuated among di-
etary species on a biweekly basis (Fig. 2b).
As the largest arboreal folivores in Su-
lawesi, bear cuscuses fill a niche occupied
by primates west of Wallace's Line and tree
kangaroos, Dendrolagus, further east. Ac-
tivity budgets of bear cuscuses are similar
to diurnal, canopy-dwelling, folivorous pri-
mates (e.g., howler monkey, Alouatta-
Crockett and Eisenberg, 1986; Milton,
1979) and presumably sloths (Bradypus
2.-Index of preferences (Jacob's
D) and density for 17 dietary species of bear
Jacob's (plants
Species of plant D /ha)
Garuga floribunda 0.021 12
Dracontomelum dao -0.230 8
Melia azedarach -0.237 13
Vitex quinata -0.374 38
Ficus variegata -0.403 9
Palaquium amboinense -0.580 54
Koodersiodendron pinnatum -0.634 8
Macaranga tannarius -0.638 7
Barringtonia acutangula -0.666 3
Cananga odorata -0.677 27
Syzygium -0.678 16
Cryptocarya bicolor -0.729 14
Alstonia ranvolfia -0.739 17
Diospyros rumpii -0.822 12
Pterospermum javanicum -0.841 12
Homalium celebicum -0.867 40
Eugenia -0.964 23
griseus and Choloepus hofinanni-Dawson
and Degabriele, 1973) in that they spent the
majority of their activity budget inactive,
usually resting and sleeping. Such skewed
activity patterns may reflect spatial distri-
bution, and nutritive characteristics of di-
etary species. In many primates that obtain
the majority of their protein from leaves,
there is a negative relationship between
proportion of time spent moving and pro-
portion of foliage in the diet (Clutton-Brock
and Harvey, 1977; Oates, 1986). The need
to move is reduced, in part, because leaves
tend to occur in large patches, which only
require short intrapatch movements to sat-
isfy feeding requirements. In addition, bear
cuscuses presumably require relatively
large amounts of food to compensate for the
low nutritional levels of their diet. Feeding
on leaves necessitates a defined post-feed-
ing, processing period to use a bulky diet
that is comprised of highly fibrous items of
low digestibility (Chapman and Chapman,
1991; Robbins, 1993). The long resting pe-
riods of bear cuscuses may be necessary be-
fore another meal can be consumed (Oates,
60 T 3OLeaf buds MYoung leaves lMature leaves
S o
o 40
S 30
4-l 20
1 2 3 4 5 6 7
Biweekly Periods
40 EGaruga floribunda OMelia azedarach LDracontomelum dao
0 30
0 20
0 0
1 2 3 4 5 6 7
Biweekly Periods
FIG. 2.-The phenological index of a) leaf
buds and young and mature leaves in consecu-
tive biweekly periods and b) young leaves for
the three most common species in the diet of
bear cuscuses.
1986; Oates et al., 1980). Extended periods
of rest also may be critical for effective use
of bacterial fermentation to breakdown cel-
lulose in the hindgut (Tyndale-Biscoe,
The significant increase in feeding activ-
ity of bear cuscuses in the afternoon may
allow for more efficient use of time if di-
gestion proceeds during the night. Chapman
and Chapman (1991) suggest that, for spi-
der monkeys, Ateles geoffroyi, late after-
noon feeding may provide calories prior to
an overnight fast, minimize travel costs as-
sociated with full stomachs, and minimize
the potential of encountering patches of
food that cannot be exploited. We are not
certain, however, that bear cuscuses restrict
their feeding activities to daylight hours. On
several occasions, we observed animals
moving within a tree after dark, and this
nocturnal activity usually followed periods
of inactivity in the late afternoon. Local in-
formants also report that cuscuses move be-
tween trees and travel on the ground during
the night. Only a few marsupials are strictly
diurnal and the amount of diurnal activity
varies with season and species (Walker,
1975). The larger kangaroos (Macropus gi-
ganteus, M. parryi, M. robustus, and M. ru-
fus), for example, are active to some extent
throughout the 24-h cycle, and in most spe-
cies, more nocturnal activity occurs in sum-
mer than winter (Kaufmann, 1974). It is
possible that activities of bear cuscuses also
are spread throughout the 24-h cycle, but
this remains to be investigated.
Bear cuscuses fed on a variety of plants,
but they showed selectivity in both species
chosen and items eaten. Dietary selectivity
may result from the need to optimize the
mix of nutrients and total bulk of the diet
(Westoby, 1974) and choose species that
contain low levels of toxic and digestion-
inhibiting chemicals (Edwards and Wratten,
1980; Freeland and Janzen, 1974; Milton,
1979; Walker, 1975). Herbivores with spe-
cialized digestive features, such as hindgut
fermentation of the bear cuscus (Tyndale-
Biscoe, 1973), are more efficient at utilizing
fibrous foods than animals without such
specializations, and they should, therefore,
be less selective in feeding. A small herbi-
vore like the bear cuscus (ca. 5 kg), how-
ever, has a proportionately smaller capacity
of its digestive tract and a higher mass-spe-
cific maintenance requirement relative to
larger herbivores, which put limits on pas-
sage rates of food. Faced with this limita-
tion, the bear cuscus may be under more
pressure to be selective in its feeding and
may not be able to tolerate as much fiber
as larger herbivores (Milton, 1979).
During our study, bear cuscuses showed
a weak preference for Garuga floribunda, a
species of canopy tree. The emergence of
G. floribunda as the most preferred species,
however, may be due more to temporal
availability of young leaves than to a strong
preference for the species. Values of Jacob's
index (Table 2) show that cuscuses display
little or no preference for most dietary spe-
cies. Rather, cuscuses display a preference
for young leaves regardless of species.
Availability of young leaves also influenced
the time spent eating a given dietary species
during any biweekly period. We expect that
preference will change for various species
throughout the year as the phenological pat-
terns of leaf emergence change. Similar
changes in foraging behavior related to sea-
sonal changes in leafing phenologies have
been shown for greater gliders, Petaurides
volans, in Australia (Kavanagh, 1984). Bear
cuscuses probably choose young leaves be-
cause they tend to be higher in protein, low-
er in condensed tannins and lignins, and
more easily digested than mature leaves
(Feeny, 1970; McKey et al., 1981; Milton,
1979; Oates et al., 1980; Waterman, 1984).
Although infrequent, bear cuscuses did
consume mature leaves. For a few species,
such as mistletoes, Cananga odorata and
Palaquium amboinense, bear cuscuses
chose mature leaves over young leaves.
Oates et al. (1980) note that Palaquium is
unusual in that mature leaves contain higher
protein than young leaves. When eating the
mature leaves of C. odorata and Pterocym-
bium javanicum, bear cuscuses were ob-
served consuming petioles and rejecting the
leaf blade. Struhsaker and Leland (1986)
observed similar behaviors by the red col-
obus monkey, Colobus badius, in Uganda
and showed that petioles of mature leaves
have fewer secondary compounds and
greater digestibility than leaf blades.
Bear cuscuses also selected flowers and
fruits of a few species when available. Bear
cuscuses consumed flower and mature
leaves of unidentified mistletoes and P. am-
boinense. Waterman (1984) reported that
flowers and mature leaves of the same spe-
cies frequently contain similar chemical
compounds. When choosing fruits, bear
cuscuses consumed greater amounts of un-
ripe fruits relative to ripe fruits. Ripe fruits
tend to have lower concentrations of nutri-
ents, especially protein (McKey, 1975; Wa-
terman, 1984), and bear cuscuses would
have to consume large quantities that pass
quickly through the gut to obtain sufficient
nutrients (Davies, 1984; Davies et al.,
1988). A fast rate of passage, however is
probably incompatible with the fermenta-
tive digestive system of the bear cuscus
(Davies, 1984; Janis, 1976; Kool, 1993;
McKey, 1975). Additionally, like foregut
fermenters, a large intake of simple sugars
may cause hyperacidity and be detrimental
to intestinal microflora (Goltenboth, 1976;
Kool, 1993).
Activity and feeding preferences of bear
cuscuses over 4 months appear influenced
by availability and nutritional composition
of foods. Choices of young leaves, petioles,
and poorly protected mature leaves are con-
sistent with choices made by folivorous pri-
mates. Presumably, folivorous primates and
cuscuses apply similar criteria for dietary
selection, despite differences in morpholo-
gy of their allimentary tract, and these
choices affect the time allocated to various
behaviors. While choice of dietary species
by bear cuscuses on Sulawesi may change
between seasons, the criteria for selection
likely remain the same.
This study was funded by the Wildlife Con-
servation Society. We thank the Indonesian In-
stitute of Sciences and the Directorate
for Nature Preservation and Forest Protection
for their assistance and permission to work in
North Sulawesi. We especially acknowledge
Mashudi, Sub Balai Konservasi Sumber Daya
Alam in Manado,
and give special thanks
to N.
and Y. Manderos for assistance
in col-
lection of data. Finally, we thank J. Eisenberg
for reviewing an earlier
draft of the manuscript.
J. 1974. Observational study of behavior:
sampling methods. Behavior, 49:227-267.
C. A., AND
1991. The for-
aging itinerary of spider monkeys: when to eat
leaves? Folia Primatologica, 56:162-166.
T. H., AND
1977. Spe-
cies differences in feeding and ranging behaviour in
primates. Pp. 539-556, in Primate ecology (T H.
Clutton-Brock, ed.). Academic Press, London, Unit-
ed Kingdom.
C. M., AND
1986. Howlers:
variations in group size and demography. Pp. 54-
68, in Primate societies (B. B. Smuts, D. L. Cheney,
R. M. Seyfarth, R. W. Wrangham, and T T Struhs-
aker, eds.). The University of Chicago Press, Chi-
cago, Illinois.
A. G. 1984. An ecological study of the red
leaf monkey (Presbytis rubicunda) in the diptero-
carp forest of northern Borneo, Ph.D. dissertation,
University of Cambridge, Cambridge, United King-
1988. Food selection by two South-east Asian co-
lobine monkeys (Presbytis rubicunda and Presbytis
melalophos) in relation to plant chemistry. Biologi-
cal Journal of the Linnean Society, 34:33-56.
1973. The cuscus
(Phalanger maculatus)-a marsupial sloth? Journal
of Comparative Physiology, 83:41-50.
EDWARDS, P. J., AND S. D. WRATTEN. 1980. Ecology of
insect-plant interactions. Edward Arnold, London,
United Kingdom.
P. P 1970. Seasonal changes in oak leaf tannins
and nutrients as a cause of spring feeding by winter
moth caterpillars. Ecology, 51:565-580.
T. 1995. Mammals of the South-West Pa-
cific & Moluccan Islands. Australian Museum/Reed
Books, New South Wales, Australia.
T. M., M. ARCHER, AND G. MAYNES. 1987.
The phylogenetic relationships of living phalanger-
ids (Phalangeroidea: Marsupialia) with a suggested
new taxonomy. Pp. 477-506, in Possums and opos-
sums: studies in evolution (M. Archer, ed.). Surrey
Beatty & Sons and the Royal Zoological Society of
New South Wales, Sydney, Australia.
W. J., AND D. H. JANZEN. 1974. Strategies
in herbivory by mammals: the role of plant second-
ary compounds. The American Naturalist, 108:269-
G. G. 1987. Characterisation of the living
species of cuscus (Marsupialia: Phalangeridae). Pp.
507-526, in Possums and opossums: studies in evo-
lution (M. Archer, ed.). Surrey Beatty & Sons and
the Royal Zoological Society of New South Wales,
Sydney, Australia.
R. 1976. Nonhuman primates (apes,
monkeys and prosimians). Pp. 46-85, in The hand-
book of zoo medicine (H.-G. Klos and E. M. Lang,
eds.). Van Nostrand Reinhold, New York.
J. 1974. Quantitative measurement of food se-
lection. A modification of the forage ratio and
Ivlev's selectivity index. Oecologia, 14:413-417.
C. 1976. The evolutionary strategy of the Equi-
dae and the origins of rumen and caecal digestion.
Evolution, 30:757-774.
T. H. 1974. Social ethology of the whiptail
wallaby, Macropus parryi, in north-eastern New
South Wales. Animal Behaviour, 22:281-369.
R. P 1984. Seasonal changes in habitat use
by gliders and possums in southeastern New South
Wales. Pp. 527-543, in Possums and gliders (A. P.
Smith and I. D. Hume, eds.). Australian Mammal
Society, Sydney, Australia.
KINNAIRD, M. E 1992. Phenology of flowering and
fruiting of an East African riverine forest ecosystem.
Biotropica, 24:187-194.
K. M. 1993. The diet and feeding behavior of
the silver leaf monkey (Trachypithecus auratus son-
daicus) in Indonesia. International Journal of Pri-
matology, 14:667-700.
McKEY, D. B. 1975. The ecology of coevolved seed
dispersal systems. Pp. 159-191, in Coevolution of
animals and plants (L. E. Gilbert and P H. Raven,
eds.). University of Texas Press, Austin.
1981. Food selection by colobus mon-
keys (Colobus satanas) in relation to plant chemis-
try. Biological Journal of the Linnean Society, 16:
K. 1979. Factors influencing leaf choice by
howler monkeys: a test of some hypotheses of food
selection by generalist herbivores. The American
Naturalist, 114:362-378.
OATES, J. E 1986. Food distribution and foraging be-
havior. Pp. 197-209, in Primate societies (B. B.
Smuts, D. L. Cheney, R. M. Seyfarth, R. W. Wrang-
ham, and T T Struhsaker, eds.). The University of
Chicago Press, Chicago, Illinois.
Food selection by South Indian leaf-monkey, Pres-
bytis johnii, in relation of leaf chemistry. Oecologia,
1996. Changing
population of birds and mammals in North Sulawesi.
Oryx, 30:150-156.
ROBBINS, C. T 1993. Wildlife feeding and nutrition.
Second ed. Academic Press, San Diego, California.
1985. SAS User's Guide: statistics,
version 5. SAS Institute, Inc., Cary, North Carolina.
R. R., AND
1981. Biometry: the
principles and practice of statistics in biological re-
search. Second ed. W. H. Freeman and Company,
New York.
T. T. 1975. The red colobus monkey. The
University of Chicago Press, Chicago, Illinois.
T. T., AND L. LELAND. 1986. Colobines:
infanticide by adult males. Pp. 83-97, in Primate
societies (B. B. Smuts, D. L. Cheney, R. M. Sey-
farth, R. W. Wrangham, and T T. Struhsaker, eds.).
The University of Chicago Press, Chicago, Illinois.
AND J. MACKINNON. 1980. Tangkoko-Duasu-
dara Nature Reserve, North Sulawesi. Management
plan 1981-1986. World Wildlife Fund, Bogor, In-
H. 1973. Life of marsupials. Edward
Arnold, London, United Kingdom.
J. R. L. 1975. The biology of plant phenolics.
Edward Arnold, London, United Kingdom.
P G. 1984. Food acquisition and process-
ing as a function of plant chemistry. Pp. 177-211,
in Food acquisition and processing in primates (D.
J. Chivers, B. A. Wood, and A. Bilsborough, eds.).
Plenum Publishing Corporation, New York.
M. 1974. An analysis of diet selection by
large generalist herbivores. The American Natural-
ist, 108:290-304.
Submitted 5 January 1998. Accepted 26 October 1998.
Associate Editor was Allen Kurta.
... The Sulawesi bear cuscus (Ailurops ursinus; Bubutu Mehmu; Suyanto et al. 2020) is one of the two Ailurops species, which form an evolutionarily distinct branch of the Phalangeridae, being recognised as the subfamily Ailuropinae, which includes the dwarf cuscus genus Strigocuscus (Dwiyahreni et al. 1999). It is the most primitive and largest species within the Phalangeridae family (Shepherd et al. 2018). ...
... Sulawesi bear cuscus feed on the leaves of trees and woody vines (Dwiyahreni et al. 1999). Unlike its closest relatives, the diminutive Strigocuscus species, which are nocturnal and largely fruit eating, A. ursinus is a large diurnal folivore, reaching a head-body length of 47-57 cm, tail length of 52-58 cm and body mass of 5-8 kg (Helgen & Jackson 2015). ...
... Unlike its closest relatives, the diminutive Strigocuscus species, which are nocturnal and largely fruit eating, A. ursinus is a large diurnal folivore, reaching a head-body length of 47-57 cm, tail length of 52-58 cm and body mass of 5-8 kg (Helgen & Jackson 2015). They are a sedentary species, spending 63.4% of their time resting and sleeping, with feeding and self-grooming accounting for 5.6% and 7.5% of their daily activity budget, respectively (Dwiyahreni et al. 1999;Talumepa et al. 2015). Little is known about A. ursinus social behaviour and communication (Dwiyahreni et al. 1999). ...
en Possum acoustic behaviour is complex and varies substantially, with some species having numerous calls used in various contexts, while other species are limited to one known vocalisation or non‐vocal sounds. Here, we report that the first known recording of Sulawesi bear cuscus (Ailurops ursinus, 1824) acoustic behaviour and observations of associated behavioural displays. We observed an animal adopting a raised posture in apparent threat display and audio‐recorded the concurrent short, harsh sounds. The animal produced a ‘chatter’, composed of four notes given at short, regular intervals, followed by a series of ‘clicks’ given at longer and irregular intervals. We describe the frequency and temporal characteristics of these sounds. Clicks were variable in acoustic structure, possibly falling into three subtypes, and some clicks overlapped in acoustic features with individual chatter notes. Click and chatter notes were broadband and non‐tonal, and so appear to be non‐vocal sounds, produced by the mouth or tongue rather than larynx. Our observations and recording of A. ursinus contribute to the natural history of this poorly known and enigmatic species, that is currently threatened with extinction from illegal wildlife trade, hunting and deforestation. Abstrak id Perilaku akustik possum bersifat kompleks dan sangat bervariasi, dengan beberapa spesies memiliki beragam panggilan yang digunakan dalam berbagai konteks, sementara spesies lain diketauhi terbatas pada satu suara vokalisasi atau non‐vokal. Di sini, kami melaporkan rekaman pertama yang diketahui dari perilaku akustik Kuskus beruang Sulawesi (Ailurops ursinus,1824) dan pengamatan dari tampilan perilaku terkait. Kami mengamati seekor hewan yang mengadopsi postur tubuh yang tampak seperti ancaman, dan merekam audio suara yang pendek dan kasar secara bersamaan. Hewan itu mengeluarkan "obrolan", terdiri dari empat nada yang diberikan secara singkat dan teratur, diikuti oleh serangkaian suara decak yang diberikan dengan interval yang lebih panjang dan tidak teratur. Kami menjelaskan frekuensi dan karakteristik temporal suara‐suara ini. Suara decak bervariasi dalam struktur akustik, mungkin terbagi dalam tiga sub‐jenis, dan beberapa suara decak tumpang tindih dalam fitur akustik dengan catatan obrolan individual. Nada decak dan obrolan adalah nada pita lebar dan non‐nada, sehingga tampak seperti suara non‐vokal, yang dihasilkan oleh mulut atau lidah daripada laring. Pengamatan dan pencatatan kami terhadap A. ursinus berkontribusi pada sejarah alami spesies yang kurang dikenal dan misterius ini, yang saat ini terancam punah karena perdagangan illegal satwa liar, perburuan dan penggundulan hutan. Abstract in Indonesian is available with online material.
... Cuscus was classified as adult males, adult females, and subadult, no individual infant was found in the observation. Adult males were identified based on large body size and prominent genital signs, in this case, the testicles and scrotum, adult females were identified based on large size and absence of prominent genital signs (testicles and scrotum), presence of adult males or presence of infant, subadult generally have smaller body sizes than adult males and females usually still live with adult males and females (Dwiyahreni et al. 1999). ...
... Grooming activities included scratching and cleansing of impurities in the individual fur (auto grooming). Social activities included mutual grooming (allogrooming), nursing, or being nursed and playing behavior (Dwiyahreni et al. 1999). Feeding data collection was carried out using the focal animal sampling method (Altmann 1974) by recording the type of diet consumed by the individual target. ...
... Data collection was carried out for each sex and age classes. The data collected is the type of diet (plant species), parts ate (fruit, leaves, flowers, etc.), feed descriptions (young leaves, old leaves, young fruit, ripe fruit, buds, etc.), and the amount of consumption of each type of diet (Dwiyahreni et al 1999). Vegetation analysis using a sample plot in the form of line compartment method, with a total of 15 plots (20 m x 20 m) was carried out to determine the diversity of vegetation species as well as the type of diet available at the study site. ...
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Daily activity and diet of Talaud bear cuscus (Ailurops melanotis Thomas, 1898) on Salibabu Island, North Sulawesi, Indonesia. Biodiversitas 20: 2636-2644. Talaud bear cuscus (Ailurops melanotis) is an endemic species in the Sangihe and Talaud Islands, North Sulawesi, Indonesia. This species is critically endangered in the IUCN Redlist, with a declining population trend. As a protected species in Indonesia, there has not been any specific research on this species. This research aimed to determine the daily activity pattern of talaud bear cuscus based on sex and age classes, and provide the first preliminary data on its dietary diversity and preference. Data collection was conducted on Salibabu Island (Talaud Islands District, North Sulawesi, Indonesia) for approximately three months (May-July 2016). The talaud bear cuscus spent most of its time resting 78.19%, moving 14.98%, feeding 3.49%, grooming 3.06%, and social 0.28%. Talaud bear cuscus fed on 22 species in its daily diet consisting of 20 tree species and 2 liana species. Cuscus fed mainly on young leaves (57.48%) followed by petioles (leaf stalk) (17.60%), mature leaves (15.33%), bud (7.19%), flowers (1.32%) and unripe fruit (1.07%). This preliminary data about the behavior, activity patterns, and diet of talaud bear cuscus, in general, can be used as supporting information in cuscus conservation efforts, especially habitat management related to the availability of feed resources and to determine the time of the survey and to understand the general behavior and ecology of this species.
... Di habitatnya, kuskus beruang lebih banyak mengkonsumsi dedaunan daripada buahbuahan (Whitten et al., 1988), terutama bagian pucuk dan daun muda (Dwiyahreni et al., 1999). Sedangkan kuskus kerdil yang juga satwa endemik Sulawesi yang bersifat aktif di malam hari (nokturnal) dan pemakan buah. ...
... Menurut Kinnaird (1997) bahwa kuskus beruang aktif di siang dan malam, sedangkan Lee (2000) melaporkan, sebagian besar waktunya dihabiskan untuk beristirahat atau tidur, dengan sedikit waktu untuk makan, merawat tubuh, dan bahkan sedikit interaksi sosial. Di habitatnya, kuskus beruang menghabiskan 64% waktunya untuk beristirahat dan 5,6% untuk makan dari keseluruhan aktivitas hariannya (Dwiyahreni et al., 1999). Sedangkan Talumepa Hal ini dikarenakan penelitian ini dilakukan di wilayah 4 propinsi, sehingga ditemukan lebih beragam pohon sarang bagi kuskus beruang yaitu 20 jenis yang tergolong dalam 13 suku. ...
... Sejalan dengan penelitian Achmad et al. (2016), kuskus beruang memilih pohon pakan sebagai pohon sarang dengan tinggi pohon lebih banyak diatas 12 meter. Sedangkan hasil penelitian Dwiyahreni et al. (1999) melaporkan menemukan 29 ekor kuskus beruang di pohon sarang dengan rataan ketinggian pohon 20 m ± 2,66 m. ...
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The objective of this study is collecting data on the selection of forest plants as feed resources and nest tree of bear cuscus (Ailurops ursinus) in North Sulawesi, Gorontalo, Central- and South Sulawesi. The bear cuscus is the largest and most primitive species of the Phalangeridae, and it is endemic of Sulawesi and surrounding islands. These animals are protected and endangered due to habitat destruction and poaching. Surveys with the roaming method are carried out by exploring the location where the bear cuscus is visible, collecting the forest plant as feed resources and nest tree. The results showed 74 species of plants consisting of 38 families was selected by bear cuscus as their feed resources and 20 species of plants as their nesting site. Parts of the feed plants being consumed were shoots and young leaves, flowers, and fruit. Keywords: Forest plant, feed resources, nest tree, Ailurops ursinus
... However, some exceptions have been reported. Dwiyahreni, Kinnaird, O'Brien, Supriatna, and Andayani (1999) observed cuscus activity in the form of tree climbing or descending to the ground to change their environment after dusk. Cuscuses most commonly appear in pairs or small groups (of up to four individuals) (Grzimek, Schlager, & Elendorf, 2003). ...
... The exact number of cuscuses is unknown. The 1993-1994 observations carried out by Dwiyahreni et al. (1999) and O'Brien & Kinnaird (1996) in northern Sulawesi reported two cuscuses per km 2 . Unfortunately, this species is endangered (The IUCN Red List of Threatened Species: Ailurops ursinus, 2008). ...
... However, some exceptions have been reported. Dwiyahreni, Kinnaird, O'Brien, Supriatna, and Andayani (1999) observed cuscus activity in the form of tree climbing or descending to the ground to change their environment after dusk. Cuscuses most commonly appear in pairs or small groups (of up to four individuals) (Grzimek, Schlager, & Elendorf, 2003). ...
... The exact number of cuscuses is unknown. The 1993-1994 observations carried out by Dwiyahreni et al. (1999) and O'Brien & Kinnaird (1996) in northern Sulawesi reported two cuscuses per km 2 . Unfortunately, this species is endangered (The IUCN Red List of Threatened Species: Ailurops ursinus, 2008). ...
Full-text available
This study described the anatomy, histology and the histochemical analysis of the eye tunics, the upper and lower eyelid, the third eyelid, the lacrimal gland and the superficial gland of the third eyelid in adult Sulawesi bear cuscus. The eyeball and the eyelids with the orbital glands were harvested immediately post-mortem. The eyeball in the Sulawesi bear cuscus had a sphere-like shape. The pupil was round, and the lens was a circular biconvex body. There was neither tapetum lucidum nor Harderian gland. Similarly, there were no eyelashes in the lower eyelid. The lymphoid follicles and the high endothelial venules (HEV) were found in the lymphoid region only in the third eyelid and in the connective tissue of the superficial gland of the third eyelid. The third eyelid in the bear cuscus resembled the letter “T.” The lacrimal gland and superficial gland of the third eyelid were multilobar tubuloacinar glands. The histological analysis and histochemical studies showed that the lacrimal gland in the Sulawesi bear cuscus produced a mucoserous secretion with predominantly serous cells. In contrast, the superficial gland of the third eyelid produced a serous secretion with a single acinus mucous in character.
... This may be the cause of the small probability of finding the movement of the cuscus during the day. Therefore, further research with the cuscus population survey method at night is necessary, considering that there is no certainty whether it is nocturnal or diurnal (Dwiyahreni et al. 1999;Repi et al. 2019). ...
Full-text available
The Talaud bear cuscus (Ailurops melanotis) has been reported from Sangihe (the largest island in the Sangihe Island group) and Salibabu (within the Talaud Islands). As an endemic species of Indonesia, this species is rare and there is no certainty regarding its precise geographic distribution or population size. This research aimed to estimate population density and provide the first preliminary data on its geographical distribution, as well as general description of its habitat. Our research shows that A. melanotis occurs on three islands: Salibabu Island, Nusa Island, and Bukide Island, and probably also exists in the Sahandaruman mountain on Sangihe Island. Our population surveys estimate, population density on each island as: Salibabu: 3.69 ± 2.54 ind/km 2 , with an estimated total population of 28.95 individuals, Nusa Island: was 12.31 ± 2.58 ind/km 2 , with an estimated population of 19.08 individuals, and Bukide Island: 7.17 ± 1.79/km 2 , with an estimated population of 10.40 individuals. Information regarding population is a key guiding factor in conservation efforts, where population size is related to extinction risk (threat status) and its geographical distribution, this can help to determine conservation priorities for species or habitats.
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The population of the bear cuscus Ailurops ursinus (Temminck, 1824), an arboreal marsupial endemic to Sulawesi, Indonesia, and its satellite islands, is declining rapidly due to poaching and habitat loss, even in protected areas. However, despite concerns over its persistence, little is actually known of this secretive species. This research investigated the characteristics of the selected habitats and diet of the bear cuscus in four ecosystem types (lowland non-dipterocarp forest, lowland limestone forest, lowland monsoon deciduous forest, lowland monsoon evergreen forest). Habitat use data were collected through direct encounters and indirect observations (tracks, signs, secondary information), and analyzed using a chi-square goodness-of-fit test. Habitat characteristics and diet availability were determined using vegetation analysis. Diet data were obtained using direct observations, feed remains, and interviews. The lowland non-dipterocarp forest ecosystem was used significantly more by bear cuscus populations. Its habitats across the four ecosystem types had similar environmental conditions. Fifty-five plant species, eaten mostly as young leaves and leaf buds, encompassed the bear cuscus’ diet, with the Moraceae family being the most representative. Considering the ubiquity of Moraceae in the bear cuscus’ habitat, these results highlight the impact unchecked deforestation will continue to have on lowland Indonesia and its endemic species.
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Kuskus, a marsupial species belonging to the Phalangeridae family that is vulnerable in the IUCN Redlist, is one of the endemic animals whose survival is currently very concerning due to habitat destruction and poaching, so conservation activities need to be carried out immediately. This study aims to identify the characteristics of the habitat, type of feed, and in situ conservation strategies in the Wakasiu forest, Leihitu Barat sub-district, Central Maluku district. This research was conducted in October 2020. Habitat characteristics were identified using vegetation analysis, forage types were identified using direct and indirect observations, and insitu conservation strategies using SWOT analysis. The highest index of importance at the tree level in the line of observation is the type of gayam (lnocarpus fagifer) (20.19%), at the level of weaning is the langsat species (70.32%) the level of the pole type of brown (69.27%). The diversity level of plant species is high and the level of evenness of plant species is even. There are 24 types of plants recorded as potential for special feed. The in-situ conservation strategy that is carried out is planting the type of feed preferred by the specialists, so as to provide a stable feed availability during the successive fruiting period. Apart from that, the restriction of hunting for specialties is through written regulations and the imposition of sanctions.
This study aimed to evaluate the microstructure of the surface of the tongue and lingual glands of the vulnerable native Sulawesi bear Ailurops ursinus. The study was carried out on five tongues collected from four adult animals and one young animal. There was variation in the shape of the filiform papillae. Few conical papillae were observed on the caudo‐lateral surface of the tongue. The gustatory papillae included fungiform papillae on the entire lingual surface and three vallate papillae, with the largest papilla located centrally. The foliate papillae were present on all the studied tongues and consisted of parallel folia on the right and left caudo‐lateral side of the tongue, which were divided into five to eight sulci. Numerous openings of the lingual glands were present on surface of the root of the tongue. Histochemical studies of the cells of the lingual glands showed the differences between young and adult animals. Thus, the composition of the secretion of these glands depends on age of animals. An aggregation of lymphatic cells was observed beneath the surface of the root epithelium. Keel (enlargement of mucosa) was present on the ventral surface of the tongue medially and was composed of the connective tissue and epithelium.
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We highlight hitherto unreported populations of two globally threatened Phalangeridae species on southeast Sulawesi’s offshore islands – Bear Cuscus Ailurops ursinus and Small Sulawesi Cuscus Strigocuscus celebensis – and observations of a third range-restricted species – Peleng Cuscus Strigocuscus pelengensis. Our data are based on records made during 11 years of seasonal surveys on Buton, and short-term expeditions to Kabaena and Manui. Our observations of S. celebensis on Buton, where it occurs in three protected areas, represent an important range extension for this species, as do our observations of A. ursinus on Kabaena, where it is also widespread. We also report the unexpected presence of S. pelengensis on Manui. Buton in particular appears to be an important stronghold for both A. ursinus and S. celebensis, given that forest ecosystems here remain extensive and relatively intact. Both these species may also display a previously unreported adaptability to disturbed forest and even some non-forest habitats within our study area. Hunting pressures, a proven threat to these species in northern Sulawesi, may also be lesser here.
Cycles of new leaf growth, flowering and bark shedding for each tree species followed a regular pattern. Phenological stages, such as the production of new leaves on the trees, yielded food of different nutrient value, and the arboreal marsupials altered their diet and feeding activities in response to these seasonal changes. The result was a seasonal pattern of selection of tree species by foraging animals. Limited migration of individuals occurred between adjacent habitat types to take advantage of higher quality food resources. The characteristics of mature forests required to maintain a dense population of arboreal marsupials include a combination of tree species having high foliage nutrients, a large proportion of 'gum' species, and a complex forest mosaic within the range of individual animals.-from Author
Relatively little data exists concerning the energy and nutrient requirements of free-living primates. In the only comprehensive investigation published Nagy and Milton (1979a) recorded an average food intake of 53.5 g/kg/day of mixed fruit and immature leaves by six howler monkeys (Alouatta palliata). Of this about 35% was assimilated, representing a field energy budget of 355 kJ/ kg/day, almost twice the reported basal rate and markedly higher than the rate of 293 kJ/kg/day recorded for two caged howlers. Our knowledge of the minimum requirements of specific nutrients is similarly scant (Kerr, 1972). Protein demand can be assumed to be at least the 1 g/kg/day recommended for man, but could be appreciably higher. Most vitamin requirements are also probably comparable to those of man. Other nutrients required include Ca, Mg, Na, K, P, Cl, S, I, Fe, Cu, Se, Mo, B, Mn and V, and possibly Al, Si, Ni, Cr, Sn, Zn and Co (Kerr, 1972; Nagy and Milton, 1979b).
The so-called 'inefficiency' of the perissodactyls, resulting from the evolution of a cecal site of fermentation, arises because the strategy of selecting fibrous herbage was developed early in their evolution. The ruminant artiodactyls did not adopt this sort of diet until they were of a sufficiently large body size for a rumen fermentation site to be physiologically possible. It appears that body size at the time of the adoption of a fibrous diet is the critical factor in determining the type of digestive system that will be evolved. Cecal digestion is in fact the superior adaptation for dealing with high fiber content herbage, provided that intake is not limited by the actual quantity of herbage available. The Equidae continued to be successful in the face of the radiation of ruminant artiodactyls because they could maintain themselves on herbage more fibrous than could be tolerated by a ruminant of similar body size.