Biology Reference
In-Depth Information
estimates 150 new infants per year based on his population estimate of 900
animals. His estimated population density of 108 animals per square kilometer
is high compared to that of some other populations. If we assume that there are
1,000 or so animals on the island it would seem extremely time consuming to
exterminate every macaque. An example might be instructive. An experimen-
tal release of a single Norway rat onto a 9.3 hectare island took almost five
months to trap (Russell
et al
.,
2005
). This was despite intensive trapping efforts
and the fact that the rat's position was known at all times via a radio transmit-
ter. Farslow (
1987
), our surveys and the statements by local people show that
the population of monkeys is much higher on the northern part of the Island,
north of the ruins of the phosphorus refinery. The macaque population has ten-
aciously survived numerous calamities. German and later, Japanese phosphate
mining as well as warfare and extensive military occupation have damaged the
island and destroyed many plants and animals (Lorenza,
1999
). In the 1930s
over 3,000 people lived on the Island. The macaques survived saturation bomb-
ing during World War II and several major typhoons, including typhoon Louise
in 1964. One man interviewed had admiration for the ability of monkeys to
survive the war. He also said that it would be a shame if there were no more
monkeys on Ngeaur after all that they went through.
Macaques can survive severe droughts and forest fires such as those in the
early 1980s in eastern Borneo (Berenstain,
1986
). They can hide and live in
the numerous coral nooks and crannies on Ngeaur Island. Furthermore, the
animals have apparently adapted to hunting and trapping pressures by ranging
in smaller-sized troops (Wheatley
et al
.,
1999b
) and by remaining silent and
out of sight (Farslow,
1987
; Wheatley
et al
.,
1999b
). Trapping is also not as
effective as it was when it was introduced (Marsh-Kautz and Wheatley,
2004
).
If trapping continues it is to be hoped that humane concerns will prompt close
attention to trapped animals. We heard a number of stories about the death
of trapped animals because the traps were not checked as frequently as they
should have been to ensure that food and water were being provided. It is
worth remembering that the Indian ban on the export of rhesus macaques was
imposed for humanitarian reasons (Eudey,
1995
). The local people of Ngeaur
are sensitive about the possibility of chemicals, whether they are poisons or
birth control hormones getting into the environment or their food supply. Thus,
all eradication measures up to now have failed. The eradication of monkeys
from Ngeaur may thus be very costly and very time consuming. Complete
eradication may even be impossible.
The various anonymous reports and pamphlets including the public aware-
ness campaign, Operation Counter-Invasion against monkeys and a vine (Anon,
2007
), almost sounds like a military offensive. The message in its entirety is
exaggerated perhaps as an effort to frighten people into controlling this macaque
