Biology Reference
In-Depth Information
In 2005, we found that much of the research site had been converted into a
captive breeding colony operated by Biodia Co. Ltd., a subsidiary of Médine
Estates, Ltd. Even though when we conducted our study the site was in many
ways “man-made”, it was relatively undisturbed and used seasonally for organ-
ized deer hunts. By 2005, Mon Vallon had been converted and there were no
free-ranging monkeys remaining at the site.
In order to follow and observe the animals in this diverse and often impene-
trable vegetation, we trapped members of two groups, tranquillized the ani-
mals, examined and weighed and measured them, and then placed radio collars
on 25 individuals (ten from one group and fifteen from the other). Trapping
techniques are described in detail in Jamieson, 1998 . Other individuals were
marked with Chinese hair dye. Radio collaring individuals of different ages
and sexes in both resident groups enabled us to follow the groups throughout
the day. Data were collected on the ecology and behavior of the animals using
five-minute scan samples of all individuals in site. Changes in the location of
the animals were noted and, even when the animals were in thick vegetation
and out of site, location of the group under observation was obtained from
the radio collared individuals. Ad lib notes were taken of all occurrences of
social interactions or of any unusual behaviors (e.g., interactions with deer,
human interference, intergroup interactions). Data were also collected on
nearest neighbor and on grooming partners when sex or individual identifi-
cations could be determined. The data were collected in all-day sessions or
partial-day sessions but were tabulated weekly with the goal of distributing
the sampling periods evenly over the day and month. Since groups were very
large and moved fairly quickly, census data were collected by two individuals
or with a tape recorder as the groups moved through open areas or crossed
roads or paths.
Some results and comparisons
Group size and structure
The two groups studied in Mauritius contained at least 85 (south group) and
72 (north group) individuals ( Table 8.1 ). The groups were multi-male/multi-
female with a sex ratio of around one male to three females. The sex ratio in
some parts of the island, however, is now likely different due to selective cap-
ture of females over males. The mean adult to immature ratio is one adult to
one to two young. Members of the large groups would leave their sleeping site
together but soon split into subgroups throughout the day. They would then
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