Studies on the food and feeding habits of Gaur Bos gaurusH. Smith (Mammalia: Artiodactyla:
Bovidae) in two protected areas of Goa
Suman
D. Gad 1 & S.K. Shyama 2
1 Research Scholar,
2 Reader, Department of Zoology, Goa University, Goa 403206, India
Email: 1 sumangad@rediffmail.com; 2 shyamask2001@yahoo.co.in
Date
of online publication 26 February 2009
ISSN 0974-7907
(online) | 0974-7893 (print)
Editor: Sanjay Molur
Manuscript
details:
Ms # o1589
Received 10 July
2006
Final revised
received 16 June 2007
Finally accepted
25 November 2008
Citation: S.D. Gad &
S.K. Shyama (2009). Studies on the food and feeding habits of Gaur Bos
gaurus H. Smith (Mammalia: Artiodactyla: Bovidae) in two protected areas of
Goa. Journal of Threatened Taxa 1(2): 128-130.
Copyright: © S.D. Gad
& S.K. Shyama 2009. Creative Commons
Attribution 3.0 Unported License. JoTT allows unrestricted use of this article in
any medium for non-profit purposes, reproduction and distribution by providing
adequate credit to the authors and the source of publication.
For Images & Tables – click here
The
Gaur or Indian Bison (Bos
gaurus)
is a major herbivore and considered a parental stock for domestic cattle. Globally, Gaur is distributed in Bangladesh,
Bhutan, Cambodia, China, India, Peninsular Malaysia, Burma, Nepal, Thailand and
Vietnam. In India, Gaur is found in
central, southern, southwestern and northeastern regions (Choudhury 2002). Studies on the food habits of wild ungulates
have been carried out in different habitats by a number of researchers. Rogers (1987) elaborated on the wild grazing
ungulates of India, including Gaur. The
activity patterns and feeding habits of gaur in Palni hills, Tamil Nadu were
studied by Sathyanarayana & Murthy (1995). Srivatava et al. (1996) carried out microhistological studies on the
food habits of Sambar, Gaur and cattle in Periyar Tiger Reserve. The food habits of wild ungulates and their
competition with livestock were studied in Pench Wildlife Reserve (Shukla &
Khare 1998). Krishnan (1972) studied the
habitat, activity patters and food habits of Gaur. Habitat analysis of Gaur in Bhagvan Mahaveer
Wildlife Sanctuary using remote sensing and GIS was carried out by Kittur
(2002). Pasha et al. (2002)
reported debarking of Teak (Tectona grandis) by Gaur during summer in
Pench Tiger Reserve. Bhagvan Mahaveer
Wildlife Sanctuary and Mollem National Park provide good habitat for Gaur. The
present study was undertaken with an aim to identify the plant species consumed
by Gaur and their feeding habits in different seasons.
Study Area
Bhagvan Mahaveer
Wildlife Sanctuary (133 km2) and Mollem National park (107 km2) (Fig. 1)
situated at Mollem in Sanguem taluk of southern Goa were selected as the study
area. The area lies between
15o15’30"-15o29’30'’N & 74o10’15"-74o20’15"E. The forest cover of this area has been
classified as tropical evergreen, semi-evergreen, moist deciduous and southern
Indian subtropical hill savannah woodland (Champion & Seth 1968). Wet and moist bamboo brakes are found
throughout the semi-evergreen and moist deciduous forests. The main rivers that flow through this region
are the Dudhsagar, Caranzol, Boma, Calem and Ragada, which branches into the
Jambauli river. The National highway
NH4A makes its way through this sanctuary. The South central railway also has its broad gauge route through this
sanctuary. Climatically, the area has
three seasons: summer (February-May), monsoon (June-September) and winter
(October-January). The area receives
monsoon from the south-west monsoon winds with average annual rainfall of 2400
mm. The terrain is plain at lower
altitudes and undulating at higher altitudes. The dominant vegetation types include Callophylum inophylum, Garciniasp., Myristica fragrans, Leea indica, Calycopteris floribunda,
Terminalia paniculata, Strobilanthes sp., Xylia, Dalbergia, Dillenia
pentagyna, Careya arborea, Grewia tiliifolia mixed with Calamus andBambusa arundinacea.
Methods
Sampling sites
in different habitats covering moist deciduous, semi-evergreen, evergreen, and
grassland habitats totaling an area of 46 km2 were selected for the present
study. Observation was done on foot and
from jeeps on motorable roads. The study was carried out for two years from
July 2004 to June 2006. Two methods were
employed for studying food habits: i) Direct observation, and ii) Faecal
analysis.
1. Direct
observation:After observing the feeding of animals through binoculars (10 x 50), on-site
inspections of food plants were made to identify plant species. A herbarium of unidentified plant species was
prepared for later identification by taxonomists. Time of feeding and atmospheric temperature
were also recorded.
2. Faecal
analysis:This was carried out by adopting procedures outlined by Satakopan (1972). Reference slides of fresh plant species
animals were observed feeding upon were prepared by taking sections of the
upper and lower epidermis of leaves, providing a key for all possible food
plants of the study area. Gaur dung
samples were collected throughout the year, except during the monsoon. The samples were oven-dried, ground coarsely
and washed in chloral hydrate solution. Permanent slides of the plant fragments obtained were prepared. The leaf fragments in these samples were
compared with the key prepared for identification from fresh plant species. Identification of plant fragments was based
on keys given by Satakopan (1972) and Johnson et al. (1983). The results were compared with field
observations.
Results
Altogether 32
species of plants belonging to 17 families were identified as food plants of
Gaur. The Gaur consumed fruits, leaves,
young shoots, bark and flowers with high preference for leaves (87%). In summer the Gaur also consumed bark of
cashew (Anacardium occidentale) and teak (Tectona grandis)
trees. The diet of Gaur is represented
by seven species of grasses, five species of herbs, eight species of shrubs and
12 species of trees. Gaur were also
observed feeding on fruits of Dillenia pentagyna (Image 1).
Species fed upon
in different seasons by Gaur are represented in Table 1. Gaur spent most of their daily time feeding
(63%). Peak feeding activity was observed in the morning (0630 to 0830 hr) and
in the evening (1730 to 1845 hr). During
hot hours of the day (1330 to 1530 hr) they were found resting in the shade of
big trees.
Discussion
We have observed
that the gaur diet consists of grasses, herbs, shrubs and trees, with high
preference for leaves. These observations are in agreement with the reports of
Shukla & Khare (1998) who reported that Gaur grazed and browsed on a much
wider variety of plants than any other ungulate species of India, with a
preference for the upper portions of plants, such as leaf blades, stems, seeds
and flowers of grass species. In
contrast, some earlier studies (Krishnan 1972; Peden et al. 1974; Reynolds
& Hawley 1987; Sathyanarayana & Murthy 1995) showed that Gaur fed
selectively in grass-dominated areas and are primarily grass eaters.
Although
Sathyanarayana & Murthy (1995) reported that Gaur prefer both finer and
coarser grasses, we observed that finer and fresh grass was preferred more as
compared to coarse grasses, and that during dry seasons Gaur browsed on tree
species. Strobilanthes ixiocephalus (Image 2) and Strobilanthes
callosus were the most preferred food plants. Preference for a particular food type showed
seasonal variation with more grass and herb species (5 spp. each) consumed in
monsoon than tree species (1 sp.). In
winter all the food classes are represented proportionately in the diet (6
grasses, 5 herbs, 7 shrubs and 6 trees). In summer maximum tree species (8 spp.) are represented as compared to
grasses and shrubs (2 spp. & 1 sp. respectively). Strong association was observed between food
preference and season (chi-square=12.94; p=0.001).
Gaur consumed
the bark of Teak (Tectona grandis) and Cashew (Anacardium occidentale)
in the summer season. This may be due to
an insufficiency of green grass in summer. Gaur are also known to feed on the bark of other tree species like Adina
cordifolia (Brander 1923; Schaller 1967; Shukla & Khare 1998), Holarrhena
antidysentrica (Ogilive 1954), Tectona grandis (Ranjitsingh 1997;
Pasha et al. 2002) and Wendlandia natoniana (Ogilve 1954). Several arguments have been put forth to
explain the probable reason for debarking behavior in different species of
mammals. The mammals may debark in
response to shortage of food resource in an area (MacKinnon 1976), a shortage
of minerals and trace elements required to meet their nutritional demands (Vancuylenberg
1977), or for maintaining an optimum fiber: protein ration for proper digestion
of food and better assimilation of nutrients (Spinage, 1974). Gaur may turn to available browse species and
fibrous teak bark in summer as green grass and herbaceous resources dry
up. In the dry season, high fibrous diet
increases the retention time of food in the gut (Owen-Smith 1988) and also
decreases the turnover rate of the rumen contents (Bell 1971). High concentrations of calcium (22400 ppm)
and phosphorus (400 ppm) have been reported in teak bark (Tewari 1992). Thus the consumption of teak bark may help
animals to satisfy both mineral and food needs.
Conclusion
The Gaur is a
generalist feeder, consuming a wide variety of grasses, herbs, shrubs and trees,
and diet composition may vary according to season and food availability. Long-term survival and conservation of
herbivores depends on the availability of suitable habitats, hence protection
of the plant species utilized by herbivores is a significant factor in
conservation biology.
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