Abstract
Social structures emerge in primate groups mainly as a response to
environmental pressures. Social structure impacts significantly on
predator detection, food gathering and reproduction, and it is
also an indicator of social condition and age and sex categories
within the group. Differentiated activities which depend on social
status, sex and age have been described in established social
groups of primates. Dominance patterns influence the behavior
of some species. It seems that the night-time spatial arrangement
of members of a primate group is an anti-predation strategy,
either by increasing detection and defensive capabilities in the
case of large sleeping groups, or by emphasizing inconspicuousness
in the case of more solitary sleepers. The persistence of social
organization during rest-activity cycles in primate groups allows
for the prediction that individuals in a group having the same
monitoring needs may alternate their rest-activity condition to
assure vigilance. In this study, we examined the rest and activity
conditions of two peripheral individuals in an established social
group of M. arctoides. Each subject was videorecorded twice for
two continous periods of 24 hours each, totaling a videorecording
of 96 hours. The rest and activity conditions observed in both
subjects were grouped in the four possible conditions:
Condition 1. Subject A resting, subject B resting;
Condition 2. Subject A resting, subject B active;
Condition 3. Subject A active, subject B resting;
Condition 4. Subject A active, subject B active.
These were compared with a concordance test. Results revealed
that peripheral males alternated their rest-activity cycles. That is,
while one subject was resting, the other remained active. The
possibility that rest-activity alternation is an adaptation to maintain
constant vigilance is discussed.
environmental pressures. Social structure impacts significantly on
predator detection, food gathering and reproduction, and it is
also an indicator of social condition and age and sex categories
within the group. Differentiated activities which depend on social
status, sex and age have been described in established social
groups of primates. Dominance patterns influence the behavior
of some species. It seems that the night-time spatial arrangement
of members of a primate group is an anti-predation strategy,
either by increasing detection and defensive capabilities in the
case of large sleeping groups, or by emphasizing inconspicuousness
in the case of more solitary sleepers. The persistence of social
organization during rest-activity cycles in primate groups allows
for the prediction that individuals in a group having the same
monitoring needs may alternate their rest-activity condition to
assure vigilance. In this study, we examined the rest and activity
conditions of two peripheral individuals in an established social
group of M. arctoides. Each subject was videorecorded twice for
two continous periods of 24 hours each, totaling a videorecording
of 96 hours. The rest and activity conditions observed in both
subjects were grouped in the four possible conditions:
Condition 1. Subject A resting, subject B resting;
Condition 2. Subject A resting, subject B active;
Condition 3. Subject A active, subject B resting;
Condition 4. Subject A active, subject B active.
These were compared with a concordance test. Results revealed
that peripheral males alternated their rest-activity cycles. That is,
while one subject was resting, the other remained active. The
possibility that rest-activity alternation is an adaptation to maintain
constant vigilance is discussed.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 34-39 |
| Number of pages | 5 |
| Journal | Salud Mental |
| Volume | 27 |
| Issue number | 6 |
| State | Published - Dec 6 2004 |