5. Discussion
Over the past 50 years, population of rhesus monkeys in Aligarh district has shown
significant and spatial distribution in terms of numbers and groups. In 1959 there were 337
rhesus monkeys spread over in 17 groups which increased to 403 individuals in 21 groups by
1962 (Southwick & Siddiqi 1983). The population after that declined irregularly and even
alarmingly to a low point of only 163 individuals in 1970 (Southwick & Siddiqi 1983). This
happened probably due to deforestation and commercial trapping of rhesus for import.
However, the rhesus population recovered after a ban was imposed in 1978 on commercial
trapping, and population increased to 669 individuals in 1991 showing a growth of 48.4%
(Imam & Yahya 1995). Further an increase was observed in rhesus population during 1993
and 1995 when 963 and 1337 monkeys were recorded in the district respectively (Imam,
2000). After a gap of 15 years (1995-2010) a remarkable change in population of rhesus
monkey was observed in Aligarh district. Since 1995, the rhesus population has registered a
growth of 203% and at present there were 4051 individuals. While comparing the number of
groups, 14 monkey groups were recorded in the district during 1995 (Imam 2000), which
increased to 84 (in 2010) showing a remarkable growth of 500% during the last 15 years. The
reason for such a high rate of growth in monkey population as well as in their group number
may be due to absence of natural predator and high natality rate. This idea is also advocated
by Imam (2000), who conducted similar study in some parts of Aligarh district and found
91.6% of average natality and only 2.1% of mortality. Probably these are the reasons because
of that population and group sizes of rhesus monkey have increased manifold.
5. DiscussionOver the past 50 years, population of rhesus monkeys in Aligarh district has shownsignificant and spatial distribution in terms of numbers and groups. In 1959 there were 337rhesus monkeys spread over in 17 groups which increased to 403 individuals in 21 groups by1962 (Southwick & Siddiqi 1983). The population after that declined irregularly and evenalarmingly to a low point of only 163 individuals in 1970 (Southwick & Siddiqi 1983). Thishappened probably due to deforestation and commercial trapping of rhesus for import.However, the rhesus population recovered after a ban was imposed in 1978 on commercialtrapping, and population increased to 669 individuals in 1991 showing a growth of 48.4%(Imam & Yahya 1995). Further an increase was observed in rhesus population during 1993and 1995 when 963 and 1337 monkeys were recorded in the district respectively (Imam,2000). After a gap of 15 years (1995-2010) a remarkable change in population of rhesusmonkey was observed in Aligarh district. Since 1995, the rhesus population has registered agrowth of 203% and at present there were 4051 individuals. While comparing the number ofgroups, 14 monkey groups were recorded in the district during 1995 (Imam 2000), whichincreased to 84 (in 2010) showing a remarkable growth of 500% during the last 15 years. Thereason for such a high rate of growth in monkey population as well as in their group numbermay be due to absence of natural predator and high natality rate. This idea is also advocatedby Imam (2000), who conducted similar study in some parts of Aligarh district and found91.6% of average natality and only 2.1% of mortality. Probably these are the reasons becauseof that population and group sizes of rhesus monkey have increased manifold.
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