Biology Reference
In-Depth Information
Long-tailed macaques go through the process of habituating to people when
human communities develop on forest edges, and over the developmental pro-
cess of lowering flight distance the macaques adjust to living more within the
anthropogenic landscape as they become more comfortable and move closer
into proximity with their neighboring humans. Aspects of this change are
developmental and learned, but there will also be components influencing a
species flight distance and ability to habituate to humans that are heritable,
as indicated by the large degree of variation in the habituation process across
species. This means that heritable aspects providing a greater ability for habitu-
ation and lowering flight distance around humans could be selected for if living
near humans has reproductive advantages.
Thus far, we have no studies on the development of human-macaque inter-
faces, and can only speculate on the time frame and processes that occur as the
two species increase in overlap. We can observe the end result of the process
though, and it is clear macaques in interface zones do have lower flight dis-
tances to people. This presents a significant change in the biotic environment
and thus presents a new exertion of selective pressures facing the macaques.
Reproductive costs will be incurred based on the degree to which people harm,
trap, kill, or otherwise remove macaques from the breeding pool (e.g., take as
pets or trade) (Eudey,
1994
; Schillaci
et al
.,
2010
;Aggimarangsee,
1992
; Louden
et al
.,
2006
; Eudey,
2008
; Lane
et al
.,
2010
). Moreover, exposure to infec-
tious agents through contact with humans (Engel and Jones-Engel, Chapter 7)
can place new selective pressures on their immune systems. Selective advan-
tages may also occur and these will be based on the amount of support, care,
and provisioning local communities provide to macaques. Human support can
increase survivorship and allow individuals to survive that might not have done
so in less anthropogenic-influenced environments (see Box 7.1). The degree of
human impact on macaque survival will vary across regions and will depend
on many of the factors studied by ethnoprimatologists, such as local cultures,
religions, and attitudes towards animals. Therefore, differing human communi-
ties will exert different selective pressures on the macaques they live with.
The important question in the evolutionary biological approach to human-
macaque sympatry is whether there are any common traits shared by the
individual macaques that are selected for or against by human activity. For
example, do macaques removed by humans (i.e., culled, killed, or otherwise
removed from breeding) tend to be less tolerant of humans and thus enter into
greater levels of overt conflict (i.e., aggression) with their human neighbors
than other individuals that are not removed? Are animals that or more passive
and relaxed around their human neighbors under less threat to be killed by their
human neighbors? Or perhaps, animals with temperaments that people prefer
(e.g., complacent and docile) are removed to be taken as pets. If we do find any
