Activity pattern of the
orphaned Asiatic Black Bear Ursus thibetanus (Mammalia: Carnivora:
Ursidae) cubs during rehabilitation processes
Soumya Dasgupta 1,
Parthankar Choudhury 2 & Parimal C. Bhattacharjee 3
1,2 Department of Ecology and
Environmental Science, Assam University, Silchar, Assam 788011, India
1,3 Wildlife Trust of India,
F-13, Sector-8, Noida, Uttar Pradesh 201301, India
1 soumya@wti.org.in, 2 parthankar@rediffmail.com
(corresponding author), 3 bhattapc@wti.org.in
Abstract: Five Asiatic Black Bear Ursus
thibetanus cubs aged between 6.5–15 months were studied for five
months using instantaneous scan sampling (n=3049 scans) while they were
undergoing acclimatization in the rehabilitation areas in Pakke Tiger Reserve,
Arunachal Pradesh, India. During
the course of the study, feeding, moving, climbing, resting and playing
activities were recorded in three consecutive time periods, representing three
phases of acclimatization. The
frequency of climbing and moving increased considerably towards the third
phase, while feeding decreased. These changes can be attributed to a learning process during
acclimatization. Time spent on moving
and playing differed significantly among the bears, but not climbing or
feeding.
Keywords: Asiatic Black Bear, India,
instantaneous group scan, Pakke Tiger Reserve, Rehabilitation.
doi: http://dx.doi.org/10.11609/JoTT.o3887.6371-5
Editor: Mewa
Singh, University of Mysore, Mysuru, India. Date
of publication: 26 September 2014 (online & print)
Manuscript details: Ms #
o3887 | Received 23 December 2013 | Final received 03 September 2014 | Finally
accepted 05 September 2014
Citation: Dasgupta,
S., P. Choudhury & P.C. Bhattacharjee (2014).
Activity pattern of the orphaned Asiatic Black Bear Ursus thibetanus(Mammalia: Carnivora: Ursidae) cubs during rehabilitation processes. Journal
of Threatened Taxa 6(10): 6371–6375; http://dx.doi.org/10.11609/JoTT.o3887.6371-5
Copyright: © Dasgupta et al. 2014. Creative Commons Attribution 4.0
International License. JoTT allows unrestricted use of this article in any
medium, reproduction and distribution by providing adequate credit to the
authors and the source of publication.
Funding: Assam University, Silchar (for logistic support) and
International fund for Animal Welfare (IFAW) and Wildlife trust of India (WTI)
for financial support.
Competing Interest: The
authors declare no competing interests.
Acknowledgements: We sincerely thank Mr. Tana Tapi,
Divisional Forest Officer, Pakke Tiger Reserve, and Mr. P.B. Rana, Range
Officer Seijusa range, for their help and support during our work. We also
express our gratitude to Mr. Aman Biri, Mr. Arun Saikia and Mr Deba Musahari
for assisting in the field work. We thank Dr. N.V.K Ashraf, Mr. Sunil Kyarong,
Dr. Kuladeep Roy, Mr. Tapajit Bhattacharya and Dr. Rahul Kaul of Wildlife Trust
of India for their valuable suggestions. We are grateful to International fund
for Animal Welfare and Mr. Vivek Menon to give us the opportunity and funding
to carry out the work.
For figures, images -- click here
The behaviour of bears varies considerably among species
(Garshelis 2004). The range of the
Asiatic Black Bear runs north-south from Russia to southern Thailand and
east-west from Japan to Iran (Servheen & Peyton 1999). Considerable work has been done on bear
activity patterns throughout this distribution range, relying primarily on
satellite or radio telemetry. These
studies have revealed that Asiatic Black Bears are diurnal (Schaller et al.
1989; Reid et al. 1991), and observations of bears in captivity also indicate that
their activities are high during dawn and dusk (Wang 1990; Hwang & Wang
1993). Most of the studies are
limited to the northern distribution range of the species in Russia, Japan and
parts of China (above 300N latitude) (Hwang & Garshelis
2007). In India, the foraging
behaviour of the Asiatic Black Bear has been studied in Dachigam National Park
(Manjrekar 1989) and Kedarnath Wildlife Sanctuary (Sathyakumar & Viswanath
2003). Studies on radio-collared bears
have also been carried out in Dachigam National Park to establish range usage
and activity patterns (Charoo et al. 2011). However, until recently, there has been
a lack of information on the behaviour of free-ranging bear cubs and their
activity in the wild. The present
study was carried out to monitor the acclimatization behaviour of five orphan
Asiatic Black Bear cubs in the wild during their rehabilitation, with emphases
on changes in behaviour patterns and variation among individuals.
Study Area
The study was conducted near Khari, 12km from Seijusa,
the divisional head quarter of Pakke Tiger Reserve located at 92036’–93009’E
& 26054’–27016′N in East Kameng District
of Arunachal Pradesh covering an area of 861.95km2 (Fig. 1). The study area is hilly with several
small rivulets traversing throughout. Cane, palms and bamboo thickets are common on the hill slopes. Dilenia indica and Alpiniasp. are common in the river margin forest. The area has a tropical climate with cold weather from November to
February. Rainfall follows a
bimodal pattern, with south-west monsoon during May to September and short
rainy period from December to April with annual mean precipitation of 2500mm
(Birand & Pawar 2004). Mean
(±SD) maximum temperature is 29.30C±4.2 and the mean minimum is 18.30C±4.7
(1983 to 1995, Tipi Orchid Research Centre).
Vegetation in the area predominantly conforms to the
Assam Valley tropical semi-evergreen forest 2B/C1 (Champion & Seth
1968). Datta & Rawat (2003)
recorded 343 species of woody flowering plants in these forests, predominated
by Euphorbiaceae and Lauraceae (Padmawathe et al. 2004). The forests are typically multi-storeyed
and rich in epiphytic flora, woody lianas and climbers. The terrain is hilly, with elevations
ranging from 100–1500 m.
Methods
We recorded the activity patterns of five Asiatic Black
Bear cubs of approximately 6–15 months of age undergoing acclimatization
for rehabilitation in the sub-tropical climate of the Indian eastern
Himalaya. Cubs were rescued from Assam
and Meghalaya (one each) and different areas of Arunachal Pradesh. These states lie within the designated
distribution range of the Tibetan subspecies of the Asiatic Black Bear Ursus
thibetanus thibetanus. As part
of the assisted release protocol (Ashraf et al. 2008) bear cubs were kept in
the in situ acclimatization enclosure in the future release area. From the time of rescue the cubs were
taken care by human rehabilitators who allowed the cubs to associate with them,
which is necessary for the in situ acclimatization process. Cubs were taken for daily walks in the
forest by the rehabilitator, and in the course of such exposure to varying
micro-habitats the cubs were expected to get acquainted with the availability
and distribution of resources, and they were also exposed to other inter and
intra-specific interactions. At the
beginning of the habituation process cubs would follow the rehabilitators and
supplementary food was kept inside the enclosure when the cubs were taken for
their daily walk away from the enclosure. Later, when the cubs were acclimatized to the habitat they were neither
dependent on the rehabilitator nor the supplementary food given inside the
night shelter enclosure. Their
activities were observed to document the process of acclimatization with their
surroundings.
The acclimatization process was divided into three
stages. In the first stage the cubs followed the rehabilitator all the times
during acclimatization walks. The
second stage began when the dependency of the bear cubs to the rehabilitator
decreased, and they began to spend time on their own. In the third stage the cubs became
completely independent of the rehabilitator, who still followed them. In all three stages supplementary food
was given to the cubs only when they came back to the night shelter enclosure
at the end of the daily acclimatization walk. Degree of exposure to the wild,
enclosure characteristics and provisioning remained the same throughout the
habituation process. The role of
the rehabilitators was limited to protection and guidance during the acclimatization
process so that cubs would not develop dependency. Monthwise data collected from the
beginning of November 2010 to the end of March 2011 were categorised as stage 1
(from 12 November to 05 December 2010), stage 2 (from 03 January to 03 February),
and stage 3 (from 26 February to 28 March). Each stage was of approximately one
month duration with a gap in between to demarcate the stages. These data were analysed to document the
advancement of the habituation process.
Instantaneous group scans (Altman 1974) were done at 10
minute intervals throughout the acclimatization process for all five cubs,
documenting activities categorised as:
Feeding - when the animal was seen taking any food
material; moving - while moving on ground; resting - when it was neither moving
nor doing anything, and sitting idle; climbing - when the animal was seen
climbing on a tree or moving up or down; playing - when it was playing with
other animal or with some non-living objects; missing - whenever the cubs went
out of sight of the observer; other activity - this includes fighting with each
other, etc. as the frequencies of
these activities were very low, they have been included as sundry (Images 1–4).
The data was analysed to compare activity frequencies
during different stages of acclimatization. Data normality was tested using
Shapiro-Wilk test. Statistical
significance of the differences was also tested using the appropriate
non-parametric tests. A similar
analytical approach was used to test the significance of differences in time
spent for different activities among the individuals.
Results
A total of 3049 scan observations (SO) on the activity
of five bear cubs were recorded and the data was analysed to find out
occurrence of various activities. Feeding was found to be the major activity (32.04%), followed by
climbing (24.63%), moving (20.04%) and playing (12.85%). Resting occurred in 2.23% of the scans
and doing other activities (0.13%) had low frequency. The cubs were missing in 8.06% of the
total 3049 scan observations (Fig. 2). As the cubs grew up and became more and more accustomed in the natural
environment, their activity pattern also showed some changes. Over time, missing observations
increased. Simultaneously, the cubs showed reduced dependency on the
rehabilitators.
To ascertain whether any substantial differences existed
in activity patterns among the cubs, the Kruskal Wallis test was applied. The cubs differed significantly in the
amount of time they spent on moving (Ho-21.089> Hc-9.488)
and playing (Ho-16.241> Hc-9.488) at df=4, but not for
climbing (Ho-1.380>
Hc-9.488)
and feeding (Ho-8.768.> Hc-9.488).
When the data was grouped into different habituation
stages (from stage-1 to stage-3) of acclimatization and the same test was
applied, the difference was statistically significant for all the major
behavioural activities including moving (Ho-43.171> Hc-23.685),
playing (Ho-25.449>
Hc-23.685),
climbing (Ho-30.567>
Hc-23.685)
and feeding (Ho-69.784> Hc-23.685) at df =14.
On analysis of the scan data it was observed that the
moving and playing activity increased through gradual advancement of
stages. Climbing activity also
increased from 1st to 3rd stage of acclimatizing process,
although it decreased in 2nd stage. Percentage of time spent on feeding and
resting decreased as the bear cubs got acclimatized further. A significant difference in the time
spent on climbing (Zo-2.864> Zc-1.960 at 0.05% significant
level), feeding (Zo-3.123>Zc-1.960 at 0.05% significant
level) and moving (Zo-2.599>Zc-1.960 at 0.05% significant level)
activities was observed, where these were found to be considerably less. But the difference was not significant
in case of playing activity, although it showed a gradual decrease from first
to third stage (Fig. 3). Missing observation also increased significantly
through gradual advancement of stages showing the success of acclimatization
process of the cubs (Fig. 4).
Discussion
All the bear cubs were hand-raised in the nursery of
Centre for Bear Rehabilitation and Conservation (CBRC) for about 2–4
months before they were released in the wild. When exposed to the rehabilitation site
the cubs were exposed to the new ambience to which they adapted gradually at
each stage of acclimatization. During the early stages of the rehabilitation
process they followed the rehabilitator and other bear cubs. Heyes (1994), and Galef & Laland
(2005) reported that social learning occurs when an animal acquires a new behaviour
as a result of observing or interacting with another animal. Fragaszy & Visalberghi (1996),
Lefebvre & Giraldeau (1996), and Reader (2003) have reported that learning
ability is correlated with large brain size, well-developed memory, behavioural
plasticity and curiosity. Bears have all these characteristic traits to learn
from the environment they are subjected to (Gittleman 1986; Gilbert 1999; Mazur
& Seher 2008). Göth & Evans
(2005) have hypothesized that even minimal parental care is worthwhile to
select for social learning. This is
most relevant in the context of social learning in black bears, since during
post natal period, the species maintains prolonged mother-cub association. During this period, cubs learn about
predators, dietary choices and also foraging sites (Gilbert 1999). The same phenomenon is pertinent for
bear cubs that have been rehabilitated in Arunachal Pradesh. With the rehabilitator, who acts as the
foster mother the cubs possibly use to learn the foraging skill and utilization
of optimum resources. Behavioural
patterns become more specialised with the gradual advancement of the
acclimatization process. In the
present study it was observed that time spent on feeding activity decreased in
the later stages of habituation as bears did not need to spend as much time
searching for food, while time spent moving, playing and climbing
increased. In the quest of better
resource availability the cubs were seen to spend more time in exploring their
wild environment, and with time they showed an increased tendency to climb
trees, consistent with the semi-arboreal behaviour of the species often
observed in wild habitats. Bear
cubs usually spend a considerable period of time on the tree canopies. On one occasion a single cub was
observed to make a nest using branches and leaves, and throughout the study
area tree nesting by wild black bears was observed quite often.
Inter-individual differences in behavioural patterns
were observed among the cubs studied. Frequencies of moving and playing differed greatly, while feeding
behaviour did not differ significantly, as primarily the cubs spent time
learning how to utilize available resources. Minor changes in foraging patterns were
observed after the cubs became acclimatized in their own home ranges. As Asiatic Black Bear tends to live a
solitary life, occasional social group formation was observed between female
with cubs or male and female during breeding time (Legakul & Mcneely 1977).
Scant information is available on the behaviour Asiatic
Black Bears, many of which are killed each year in north east India as a result
of man-animal conflicts. Cubs are
often kept as pets, and when they become a nuisance they are either killed or
handed over to the forest department. Studies of their habitat acclimatization behaviour are important for successful
rehabilitation of such bears, and it is hoped that the present study will help
to provide baseline information to aid this process.
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