Biology Reference
In-Depth Information
size by 41 percent, group 2 decreased by 4.5 percent, and group 3 increased in
size by 173 percent. This may suggest that groups 1 and 2 were impacted most
severely by the streptococcus outbreak in 1994 which caused high mortality in
many macaque groups in central Bali (see
Table 6.1
). However, local temple offi-
cials and villagers have stated that group 3 suffered significant losses as well. The
demographic patterns between 1992 and 1998 at this site remain unclear.
Wheatley (
1999
) also reports a relatively cohesive all male group from
1990-1992 at Padangtegal. We observed frequent play groups composed of
juvenile and sub-adult males from either group 2 or group 3. Occasionally
young males from both groups formed a play group in the space between
groups. However, these play groups were temporary lasting from a few min-
utes to multiple hours. There was no evidence of any permanent or temporally
cohesive male groups. It is possible that the increase in overall population has
created substantial peer clusters within each group and led to the reduction in
inter-group play by immatures.
In 1999, a new management program was initiated which included removal
of plastic and other wastes from the forest, anti-erosion control, reclamation
and re-forestation of fields bordering the forest, and occasional medical care
for injured or sick individual macaques. It is clear that this change in manage-
ment style combined with the increased diversity, amount, and regularity of
provisioning, as well as the increased tourist presence and feeding from them,
resulted in the population increasing in size at a dramatic rate.
The number of new infants in the May-August birth peak (
Table 6.2
) has
increased annually. These births make up approximately half the annual births.
Anecdotal information suggests that rate of increase have continued through
2010 with estimates of the current population nearing 500 individuals (see
Box 6.1).
As the diet of this population is heavily provisioned, the death rate is fairly
low and infant mortality appears low as well, population growth appears to be
primarily curbed by epidemics and at least two have occurred between 1986
and 2002. This suggests that pathogen environment may be a significant select-
ive force on these macaques. A significant role for epidemics/disease has also
been proposed for the semi-free-ranging population of macaques (
Macaca syl-
vanus
) in Gibraltar (Fa and Lind,
1996
; O'Leary and Fa, 1993) and a large
population of chimpanzees in Tanzania (Nishida
et al
.,
2003
).
Immigration/emigration
Koyama
et al
., (
1981
) report the immigration of two adult males into this
population. Wheatley did not observe any immigration and we observed
