close

Вход

Забыли?

вход по аккаунту

?

Aspects of fight interference in free-ranging and compound-dwelling rhesus macaques (Macaca mulatta).

код для вставкиСкачать
American Journal of Primatology 12:287-298 (1987)
Aspects of Fight Interference in Free-Ranging and
Compound-Dwelling Rhesus Macaques (Macaca rnufatta)
JAY R KAPLAN,' DENNIS K CHIKAZAWA,' AND STEPHEN B MANUCK3
'Bowman Gray School of Medicine of Wake Forest University, Winston-Salem, North
Carolina, 'Yerkes Regional Primate Research Center, Emory University, Atlanta, Georgia,
3Un1versity of Pittsburgh, Pittsburgh, Pennsylvania
Pat terns of fight interference (agonistic aiding) were compared among three
groups of rhesus monkeys (Macaca mulatta) living in two settings: 1)two
groups a t Cay0 Santiago (Caribbean Primate Center); and 2) one group a t
the Yerkes Regional Primate Research Center (YRPRC). A total of 1,227
interference episodes were recorded in 1,650 hours of observation. The only
significant intergroup difference was the increased tendency of males at
YRPRC to aid aggressors rather than victims. Among other findings, females aided relatives, interfered against target animals dominant to themselves, aided juveniles, and aided victims more consistently and frequently
than did males. Importantly, female interference became more male-like in
pattern when aid was given to nonrelatives. Neither the dominant males
nor males in general displayed a unique or consistent tendency to interfere
in fights in a manner which could be interpreted as controlling aggression.
The males' interference patterns also did not suggest they were forming
coalitions to either attain or defend status rankings. It is concluded that,
overall, observations of compound-dwelling and free-ranging rhesus monkeys reveal similar relationships. Further, while female rhesus monkeys
interfered in fights in a manner consistent with the control of aggression
and protection of kin, the motives of male interferers remain unknown;
however, their behavior is consistent with the hypothesis that they were
reducing intermale tensions while, a t the same time, minimizing physical
risk.
Key words: interference, agonistic aiding, rhesus macaques, primates, Macaca mulatta
INTRODUCTION
Social behavior within a species is believed to vary as a function of ecological
setting or demographic conditions [eg, Gartlan & Brain, 19681; however, the degree
and significance of this variability is difficult to gauge as the relevant data are most
often collected by different investigators, with little uniformity in collection tech-
Received Marc:h 5, 1986; revision accepted November 2, 1986.
Address reprint requests t o Jay R. Kaplan, Ph.D., Bowman Gray School of Medicine, Department of
Comparative Medicine, 300 S. Hawthorne Road, Winston-Salem, NC 17103.
0 1987 Alan R. Liss. Inc.
288 I Kaplan, Chikazawa, and Manuck
niques or methods of analysis. Additionally, investigators typically examine only a
single group within any given condition or setting, making it difficult to establish
the extent of variability that reasonably may be expected within a location. It
seemed especially important to us to examine variability in the occurrence of fight
interference (also termed agonistic aiding or third party interference [Bernstein &
Ehardt, 198511, as this behavior has been utilized to evaluate social bonding networks within groups and also to test hypotheses concerning sociobiology, dominance
rank, and kinship [Trivers, 1971; West-Eberhard, 1975; Kurland, 1977; Kaplan,
1978; Bernstein & Ehardt, 19851. In the current study, aspects of fight interference
are reported for three social groups of rhesus monkeys (Mucaca mulatta) living in
two disparate conditions: a) two groups free-ranging at the Cay0 Santiago (CS)
station of the Caribbean Primate Center; and b) one group dwelling in a 38 m x 38
m compound a t the Yerkes Regional Primate Research Center (YRPRC). The data
were collected and analyzed utilizing identical techniques.
One objective was to determine the extent and nature of variability in interference behavior, especially the manner in which compound-dwelling monkeys differed
from their free-ranging counterparts. A further objective was to determine the
robustness of fight interference patterns reported previously a t both CS and YRPRC.
Such observations showed, for example, that males and females differed significantly in their patterns of aiding, with females aiding kin, and with the beneficiaries
of such aiding often being victims of aggression [Kaplan, 1977, 1978; Bernstein &
Ehardt, 19851. The current data were used also to consider two unresolved issues
relating to interference behavior in macaques: a) the motivation of males to interfere, especially when the interference is on behalf of aggressors; and b) the existence
of a “control role,” occupied by dominant males. A control role has been reported in
some, but not all, groups of rhesus monkeys as well as in other macaque species.
METHODS
Study Sites, Animals and Data Collection
The study animals consisted of groups M (termed “Cl” in the current study)
and L (“CB”) from CS, and group R-9 (“Yl”) a t the YRPRC (Table I). Behavioral
observations were made by one investigator (JRK) on group C1 from March, 1974
through July, 1975 (950 hours) and on group C2 from January, 1974 through July,
1974 (450 hours). Observations were made by JRK on group Y1 in July and August,
1977. These observations were continued by another investigator (DKC) from September, 1977 through February, 1978 (250 hours, total). All of these groups had been
monitored previously by a number of other investigators, hence their social histories
were well known [Sade et al, 1977; Chikazawa et al, 19791.
Notes by JRK were taken with ad libitum sampling [Altmann, 19741 and
described, in detail, all interactions occurring between individual monkeys, between
groups and subgroups, and relationships between monkeys and their nonsocial
environments [Kaplan, 1976, 19771. Notes by DKC were taken in abbreviated diary
fashion, with the emphasis on grooming and fight interference interactions. It is
recognized that the ad libitum sampling procedure does not provide a random
sample of the rate of occurrence of interference or any other specific behavior;
however, it is assumed that the pattern of interference observed on the part of each
animal represented a random sample of all interferences performed by that animal
[cf Hausfater, 19751.
All notes were tabulated by JRK using the same criteria for identifying the
occurrence of interference episodes. Specifically, interference was defined as a n
episode in which a monkey entered a n ongoing or just-terminated agonistic bout
(fight) that began as a dyadic encounter between two other monkeys [Kaplan, 1977;
see Sade, 1967, 1972 for definitions of “fight,” “episode,” and “bout”]. An earlier
Fight Interference in Rhesus Macaques I 289
TABLE I. AgelGender Composition of Groups Y1, C1, and C2
Group
Y1
c1
c2
Infants-Juveniles
(< 3Yr)
Males
Fema1es
18
17
14
17
10
8
Adolescents-Adults
( 2 3Yr)
Males
Females
16
12
17
22
15
24
study had shown that, in rhesus monkeys, the interfering animal almost always
aids one of the original combatants against the other [Kaplan, 1974, 19761. Thus,
three roles are represented in each interference episode: a) the interferer; b) the
beneficiary of the interference; and c) the target. Additionally, beneficiaries can be
distinguished by their identification as victim or aggressor in the original fight.
Comparison of behavioral data taken by JRK and DKC on group Y1 revealed no
significant differences in patterns of fight interference, grooming, or dominance
[Kaplan & Chikazawa, 19781.
Ana1y ses
Previously published analyses of rhesus monkey interference behavior have
been based on the summation of episode frequencies within classes of animals (eg,
all males, all females, all adults) [Kaplan, 1977, 1978; Bernstein & Ehardt, 19851.
This is because the data were collected ad libitum, making true rates of interaction
impossible to determine. However, such analyses have the potential to distort the
contributions of animals which interfere frequently, if such animals are acting
idiosyncratically. Further, the use of summed frequencies generally limits analyses
to nonparametric techniques (C‘Z” tests or repeated x2).
Data in the current study also were collected ad libitum. However, we sought to
avoid potential problems in the use of frequency data summed within classes by
creating for each animal a series of four indices based on the percentages of their
interference episodes which were directed toward different categories of beneficiaries
or targets: a) the percentage of interference episodes in which the beneficiary was a
victim in the original fight; b) the percentage of episodes in which the interferer was
dominant to the target animal; c) the percentage of episodes in which (for natal
animals only) the interferer was related to the target animal; and d) the percentage
of episodes in which infant-juveniles were aided. These calculations reflect the four
factors reported previously as significant determinants of interference patterns: a)
role of the beneficiary (victim or aggressor in the original fight); b) status of the
interferer relative to the target animal (dominant or subordinate);c) the genealogical
relationship between the interferer and the beneficiary (related or not related); and
d) age of the beneficiary (infant-juvenile, < 3 yr; adolescent-adult, 2 3 yr) [Kaplan,
1977, 19781.
To be included in the primary analyses, an animal had to be an adolescent-adult
and had to have interfered at least five times. The data from all animals which met
these criteria were then included with equal weight in a series of analyses of
variance (ANOVA), comparing male and female interferers within and between
groups. Analyses of covariance were then applied to the data in order t o demonstrate
that the patterns revealed by the ANOVAs were not influenced by the differing
number of episodes contributed by individual monkeys. In these latter analyses, the
number of interference episodes performed by each individual (range 5-49) was used
as the covariate. None of the covariance analyses resulted in alteration of the
original ANOVA results; the covariance analyses, thus, are not reported in the text.
290 I Kaplan, Chikazawa, and Manuck
In addition to the above analyses, post-hoc tests and nonparametric evaluations
were performed as needed. The inclusion of data from adults only provided for a
relatively homogeneous data set, and the inclusion criterion of five episodes provided
a reasonable lower limit for representation in the study. Males natal and non-natal
to the social groups were considered together for all analyses except the relative vs nonrelative comparisons.
Of the 1,227 recorded episodes of interference, 80% were performed by animals
meeting the above inclusion criteria, 6% were performed by adults with less than
five interferences each, and 14% were performed by juveniles. Of the 106 adults in
the three groups, 60% contributed data to the analyses; these animals performed a n
average of 15.76 ( & 1.30 SEM) interferences. While the primary analyses were
performed on the percentage indices of interference, parallel x2 analyses were
applied to the total adult frequency data in order to demonstrate the robust nature
of the results and their comparability to previously published results. All tests of
significance were two-tailed.
RESULTS
Genealogical Relationship Between Interferers and Beneficiaries
The mean percentage of episodes in which males and females (natal only) in
each group aided relatives is shown in Table 11. Females interfered on behalf of
relatives considerably more frequently than did males. A Gender male,female x Group
C ~ , C B , YANOVA
~
applied to the data revealed a significant main effect for Gender
(F[1,52] = 53.44, P < 0.001). Neither the Group main effect nor the Group x Gender
interaction was significant.
Because the data violated somewhat the parametric assumption regarding homogeneity of variance, additional analyses (t-tests)were performed on the data from
each group separately. These analyses showed, also, that males interfered on behalf
of relatives significantly less than did females (Cl: t = 3.04, P < 0.01; C2: t = 3.68,
P < 0.01; Y1: t = 6.43, P < 0.001). A comparison of the percentage of aid given by
females to relatives revealed no differences among the three groups (F[12,41] =
0.63, NS). The rather consistent percentage of aid given to relatives by females was,
despite the increased opportunities for relative aid among the animals from C1,
where the percentage of dyads containing relatives was higher than in the other two
groups (Cl: 22% dyads related; C2: 15% dyads related; Y1: 12% dyads related).
Role of the Beneficiary
The percentage of episodes in which male and female interferers in each group
aided victims (rather than attackers) are shown in Table 111. A Gender x Group
ANOVA applied to these data revealed main effects for Group (F[2,57] = 7.83, P <
0.01) and Gender (F[1,57] = 14.68, P < 0.01), as well as for the Group x Gender
interaction (F[2,57] = 4.71, P < 0.02). An initial interpretation of these data is that
TABLE 11. Percentage of Aid Given by Natal Males and Females to Relatives (+ SD)*
Gender
c1
Grom
c2
Males
56 (15)
n=4
85 (17)
n = 15
n=4
83 (20)
n = 11
Females
35 (30)
Y1
38 (10)
n=6
78 (14)
n = 18
*ANOVA: Gender, F[1,52] = 53.4, P < 0.001; Group, F[2,52] = 2.21, P > 0.10; Group x Gender,
F[2,52] = 1.09, P > 0.20.
Fight Interference in Rhesus Macaques / 291
TABLE 111. Percentage of Aid ( & SD) Given by Interferers to Victims of Aggression in
Groups Cl, C2, and Y1*
Group
Gender
c1
Males
68 (16)
n=8
62 (30)
30 (19)
n=5
n=6
76 (16)
n = 15
72 (22)
n = 11
70 (14)
n = 18
Females
Y1
c2
*ANOVA: Gender, F[1,57] = 14.68, P < 0.001;Group, F[2,57] = 7.83, P < 0.001; Group x Gender,
F[2,57] = 4.71, P = 0.01.
while animals in general aided victims of aggression (67% of instances), females
were more likely than males to aid victims. Further, there was variability across
groups, with[ the animals in group Y1 significantly less likely than other animals to
aid victims of aggression. Finally, there was a more marked male-female difference
in group Y l than in the other groups. Subsequent contrasts among group means a t
P < 0.05 [Kirk, 19681 suggests some qualification of this interpretation. The propensity of females to interfere on behalf of victims was significantly greater than that
of males only in group Y1. This finding suggests, in turn, that most of the observed
ANOVA effects resided in the Y1 males (ie, if these males were similar to the C1
and C2 males, the overall male-female difference probably would have been of only
marginal significance).
Given the significant influence of kinship on female interference, we tried to
determine whether the percentage of aid given by females to victims might have
been conditioned, in part, by genealogical relationships. Here, the analysis was
limited to animals which interfered more than five times on behalf of both relatives
and nonrelatives (n = 9 males, n = 6 females). It was found that when interfering
on behalf of' relatives, females were significantly more likely to aid victims than
were males (females: = 67% (+ 22 [SD]) aid to victims; males: =43% (+ 15); t
= 2.15, P : < 0.05). However, when these same animals aided nonrelatives, the
percentage of aid by females and males to victims could not be distinguished
(females: X = 53% (+ 18);males; X = 53% (+ 15); t = 0, NS).
x
x
Age of Beneficiary
The percentages of aid given by adolescent-adult interferers to infant-juveniles
are shown in Table IV.A Gender X Group ANOVA applied to these data revealed
only a signiificant Gender effect (F[1,57] = 10.64, P < 0.01). Mean values indicated
that females were significantly more likely to aid infant-adolescents than were
males. While about half of the animals in groups Y1 and C1 were infant-juveniles
(Table I), this was true for only 35% of the animals in group C2. Despite this
variability, however, there were no group differences in propensity to aid infantjuveniles as opposed to adolescent-adults. As with aid to victims, it was hypothesized
that genealogical associations might have influenced the relatively high amount of
aid given by females to infant-juveniles. Again, the analysis was limited to those
animals interfering on behalf of relatives and nonrelatives a t least five times (n = 9
males, n = 6 females). When interfering on behalf of relatives, females helped
juveniles mlore than did males (females: X = 50% ( 5 26) aid to infant-juveniles;
males: X = 23 (k 23); t = 2.24, P < 0.05). However, males and females could not be
distinguished when aiding nonrelatives (females: X = 27% (+ 17); males: = 28%
(+ 281, NS).
x
292 I Kaplan, Chikazawa, and Manuck
TABLE IV. Percentage of Aid Given by Adolescent-Adult Male and Female Interferers to
Infant-Juveniles*
c1
Gender
Males
Fema1es
*ANOVA: Gender, F[1,53] =
F[2,57] = 0.55, P > 0.20.
Group
c2
Y1
37 (20)
31 (19)
n=8
n=5
58 (21)
41 (21)
n = 15
n = 11
10.6, P < 0.01; Group, F[2,57] = 1.91, P > 0.10; Group x
25 (14)
n=6
50 (21)
n = 18
Gender,
TABLE V. Percentage of Episodes (& SD) in Which Interferers Were Subordinate to
Target Animals
Gender
c1
Group
c2
Males
2 (6)
n=8
38 (19)
n = 15
3 (8)
n=5
46 (18)
n = 11
Females
Y1
0 (0)
n=6
46 (27)
n = 18
Status of the Interferer (Dominant or Subordinate to the Target)
The percentages with which males and females of each group interfered against
animals which were dominant to them are shown in Table V. Inspection of this table
reveals that males rarely interfered in fights if they were subordinate to the target,
while females were often subordinate to the target. Because of the depressed variability among the males (with means and SDs close to 01, a series of Mann-Whitney
U tests (two-tailed) were applied to the data, comparing males and females within
each group. These analyses revealed that the females in all three groups interfered
in fights in which they were subordinate to the target animal significantly more
frequently than did males (all P values < 0.01).
WhiIe males were similar across groups in not interfering in fights if they were
subordinate to target animals, females were similar in the tendency for about 40%
of their interferences to be performed while subordinate to the target animal. An
ANOVA applied to the data involving females indicated no significant differences
between groups (F[2,41] = 0.66, NS). Although females showed a slight tendency to
interfere more frequently when subordinate to the target if they were related to the
beneficiary than if not, the difference was not significant (females [n = 61 aiding
relatives:
= 37% (+ 23) subordinate to target; females aiding nonrelatives:
=
30%(+ 24); t = 0.77, NS).
x
x
Dominant Males and the “Control Role” Concept
We sought to determine whether the dominant males may have, more than
other animals, helped to “control” aggression in their groups. This was done by
evaluating the extent to which the two highest ranking males in each group aided
victims, rather than aggressors, when they interfered. Additionally, we examined
the pattern with which these dominant males occupied the target and beneficiary
roles in interference episodes.
There was considerable intergroup variability in the degree to which dominant
males aided victims rather than aggressors; within groups, however, the dominant
Fight Interference in Rhesus Macaques I 293
TABLE VI. Interference Pattern of the Two Most Dominant Males in Each Group
Percentage
aid to
No. as Percentage as
No. as
Percentage as
Group Male interferer victims target
aggressor
beneficiary
aggressor
No. as
C1
M1"
M2"
C2
Mlb
Y1
M2"
Mlb
M2b
37
38
14
7
22
23
76
82
64
46
36
26
15
31
14
33
14
21
100
90
100
100
100
86
7
4
9
16
2
7
100
75
89
94
100
71
'Nonnatal to the group.
bNatal to the group.
males appeared comparable (Table VI). Thus, for example, the dominant males in
Y 1 both aided victims less than aggressors and differed significantly from females
in this pattern (cf Table 111)(P < 0.01, Mann-Whitney U). On the other hand, the
dominant males in C1 aided victims more than aggressors and did not differ from
females in t h i s pattern (P > 0.20, Mann-Whitney U). The two most dominant males
from C2 aided victims and aggressors approximately equivalently and, although
their percentage values were below the mean percentage of aid given to victims by
females, the difference was not significant (0.20 > P > 0.10, Mann-Whitney U).
Importantly, further analyses showed that the two highest ranking males in each
group could not be differentiated from other males in their groups in the extent to
which victimis or aggressors were aided (all P > 0.20, Mann-Whitney U); hence, in
terms of their pattern of aid to aggressors and victims, dominant males were not
uniform in their "control" of aggression, nor were they unique and distinct from
other animals in this aspect of interference.
Further evaluation of the data (Table VI) indicates that these six dominant
males were themselves the targets of interference (almost always as aggressors)
approximately one and a half times a s frequently as they helped victims. Also, while
dominant males were sometimes the beneficiaries of interference behavior, this was
almost always when they were aggressors rather than victims. In fact, the data
show that dominant males in all groups either aided aggressors or were involved in
interference episodes a s aggressors (while targets or beneficiaries) almost three
times as frequently as they aided victims.
Evaluation of Frequency of Interference by Subclasses
Table V[I shows the summed frequency of interference a s performed by all
adolescent-adult animals in each of the three social groups (including the 69 episodes
performed bj7 the 43 monkeys which interfered less than five times each). A series
of chi-square tests applied to these data revealed results almost identical to those
obtained above with the use of the percentage indices. Thus, for example, males in
general were less likely than females to aid victims of aggression (x2 = 32.0, P <
0.01), and the animals of group Y1 were less likely than were the animals of other
groups to aid victims of aggression (x2 = 19.2, P < 0.01).Further analysis shows
that females interfered more on behalf of victims than did males in groups C2 (x2 =
5.94, P < 0.03) and Y1 (x2 = 45.6, P < 0.011, but not in group C1 (x2 < 1.0, NS).
Similar analyses showed that males in all groups interfered in fights only when
dominant to the target animal (x2 = 18.4, P < 0.011, that males were less likely to
aid relatives than were females (x2 = 124.9, P < 0.011, and that males showed a
lesser tendency to aid infant-juveniles than did females (x2 = 34.9, P < 0.01). The
294 I Kaplan, Chikazawa, and Manuck
TABLE VII. Summed Frequency of All Interference Performed by Adolescent-Adult
C1. C2,
C2. and Y1
Animals of C1,
Group
c2
c1
~~
Y1
Male
Female
Male
Female
Male
Female
Aid victim
Aid attacker
Dominant
118
52
234
87
24
21
99
37
40
82
176
77
to target
Subordinate
to target
Aid relative
Aid nonrelative
Aid juvenile
Aid adult
168
201
44
72
121
140
2
45
30
61
109
120
271
50
179
142
1
8
20
14
31
64
114
22
53
82
1
39
68
28
93
113
200
53
126
127
ANOVAs reported above (on the percentage indices) allowed for a somewhat more
precise description of these effects.
DISCUSSION
Intergroup Variability
The three rhesus monkey study groups (Cl, C2, and Y1) differed in a number of
ways, each of which could have influenced the expression of interference behavior.
Most obviously, groups C1 and C2 were free-ranging, with animals able to avoid
unwanted interactions with other animals through the use of cover or through
timely departures from locations of conflict. On the other hand, the monkeys of Y 1
were in relative proximity to each other on a continuous basis. Additionally, the
spontaneous migration of animals (especially males) into and out of social groups
which occurred at CS [Kaplan, 19761 was precluded in Y1. As a result, the ratio of
natal to non-natal males was greater in Y1 than in C1 or C2. Finally, many of the
Y 1 males were, as adults, subordinate to many of the adult females. In groups C1
and C2, on the other hand, most adult males were non-natal and most were dominant to most females. These are the kinds of differences that sometimes are suggested as capable of causing signficant alterations in patterns of social behavior
[Rowell, 19721.
Interference behavior was relatively uniform in pattern of occurrence, given the
demographic and ecologic variability among these groups. Females were especially
consistent in aiding relatives and victims, while males were particularly consistent
in aiding when dominant to the target and in aiding older, rather than younger,
animals. Although there was behavioral variability among groups, the only significant difference in interference behavior related to the increased likelihood of Y 1
males (including the dominant males) to aid attackers rather than victims. It is
tempting to suggest that such a difference resulted from the increased visibility
present in the corral situation and the greater willingness of males under these
conditions to join in attacks on victims rather than to defend such animals (see
below). Given that this was the only significant difference among groups, it can be
concluded that variability in interference behavior between groups living under
ecologically disparate conditions, as well as between groups in a single location, is
relatively minimal.
Fight Interference in Rhesus Macaques I 295
Comparative Studies
The data presented in this report go beyond providing a comparison of conspecific rhesus monkey groups living in free-ranging and compound environments. The
data offer also the opportunity to evaluate the robustness of previously reported
findings on rhesus monkeys, particularly those from CS and YRPRC. For example,
data from CS and YRPRC indicate that aid is more often given to victims than
aggressors; however, male and female patterns of interference were reported to be
different, with females giving more aid overall, and aiding victims and relatives and
interfering as subordinate to the target more frequently than males [Kaplan, 1977,
1978; Bernstein & Ehardt, 19851. On the other hand, males appeared to aid a t little
risk to themselves (ie, when dominant to the target), and did not seem to “control”
intergroup aggression, as has sometimes been suggested for other species of macaques, such as M. fuscata [Tokuda & Jensen, 1968; Watanabe, 19791 and M. nemestrina [Oswald & Erwin, 19761.
The data reported in the current manuscript are largely consistent with these
previous results. Thus, in C1, C2, and Y1, victims, overall, were aided significantly
more often than aggressors. Additionally, four male-female differences consistent
with earlier findings were observed among the three groups: a) females were more
active than males in aiding relatives; b) females were more active than males in
aiding against target animals dominant to themselves; c) females were more likely
than males to aid infant-juveniles; and d) overall, females were somewhat more
likely to aid victims of aggression than were males, though this effect was appreciable (and indeed statistically significant) only in group Y 1. Finally, the dominant
males failed to show any uniform or unique tendency to occupy a control role
(protecting victims in fights). Significantly, the above patterns of interference were
present whether the data were evaluated on the basis of summed frequencies within
subclasses, or on the basis of equivalent individual contributions (the percentage
indices).
As a whole, the data from CS and YRPRC suggest that the interference patterns
of male and fismale rhesus monkeys are distinct. Further, these patterns are consistent with the hypothesis that a major activity of (adolescent-adult) female rhesus
macaques is to control aggression, especially as it affects their kin, while males
interfere in ai manner which minimizes their risk (because they almost never aid
when they are subordinate to the target animals) and which does not relate specifically to the control of aggression (because relatively often they aid aggressors rather
than victims:l. Similar male-female differences have been reported in pigtail and
cynomolgus macaques (M. nemestrina, M. fasicularis) [Massey, 1977; de Waal, 19771.
Marked gender differences in aiding patterns exist also among chimpanzees (Pan
troglodytes) [de Waal, 1984; Nishida, 19831. It is worth noting that the gender
differences observed a t CS and YRPRC may have been dependent, a t least in part,
on genealogical relationships. Thus, it was found that when females aided nonrelatives, they dild so in a pattern that was much more male-like than when they aided
relatives (males did not change their pattern of aiding as a function of genealogical
associations). Based on such a finding it might be speculated that the interference
patterns of females living in groups not characterized by genealogical and long-term
peer associations would converge strongly with those observed among males. In fact,
a recent report describes the interference behavior within artificially formed groups
of adult female cynomolgus macaques as being male-like [Kaplan & Manuck, 19851.
Unresolved Issues
The current data leave several issues unresolved. The pattern and motivation
of male interference, in particular, is problematic. For example, data in the current
296 1 Kaplan, Chikazawa, and Manuck
and previous studies show that males a t CS aid victims of aggression more frequently than aggressors, while males at the YRPRC consistently aid aggressors
more than victims [Kaplan, 1977, 1978; Datta, 1983; Bernstein & Ehardt, 19851. De
Waal [1977] suggested that the tendency to aid aggressors under confined circumstances might be related to the increased degree of tension presumably existing
between high ranking males forced to live in close proximity; aiding each other
against lower ranking animals (“scapegoating”) may help release such tensions.
Alternatively, or in addition, we would suggest that the increased visibility in
closely confined conditions (such as experienced by the males of group Y1) may cause
males to more completely reduce risk to themselves by only becoming involved in
those fights in which the target is already losing (ie, is a victim). Importantly, it does
not appear that these rhesus males often use interference behavior as a means of
raising their ranks relative to the targets against which they are interfering, since
they are almost always already dominant to the targets. Whether some of the
interference episodes of males represent coalitions helping to maintain status distinctions, such as has been suggested for baboons [Packer, 19771, awaits the collection of more detailed data.
A further unresolved issue relates to the control role. Numerous authors have
contended that dominant macaque males play a control role by breaking up fights
and punishing aggressors [Bernstein & Sharpe, 1966; Kaufmann, 1967; Kurland,
1977; Watanabe, 19791. The data reported above do not support, among rhesus
monkeys, the existence of a control role consistently filled by dominant males. An
examination of the criteria used to evaluate the presence of the control role may, in
part, resolve the issue. Usually, a major criterion for the presence of a control role is
whether aid is given to victims rather than agressors [de Waal, 1977; Kurland, 1977;
Watanabe, 19791. A less frequently used criterion is whether agonism (overall, or
within specific agelsex categories) increases with the removal of the supposed control
animal [Tokuda & Jensen, 1968; Oswald & Erwin, 1976; Erwin, 19791.
Unfortunately, there appears to be considerable inter- and intra-species variability in both of these phenomena. However, if fight outcomes are carefully evaluated, a more consistent result may emerge. For example, de Waal [1977] showed
that although the dominant male of each of his small cynomolgus macaque groups
was active in helping victims of aggression, the fight interference of the dominant
males had three characteristics: a) these males were not more effective than other
animals in stopping aggression; b) they were no more protective than other animals;
and most importantly c) their participation in fights tended (whether helping victims
or aggressors) to increase the overall level of aggression. This suggests that where
dominant males are reported to occupy a control role, the effect may be more
apparent than real. Further diminishing the potential importance of direct male
interference behavior is its relatively low frequency in comparison to that of females
[Bernstein & Ehardt, 19851. Clearly, additional, detailed studies are needed to
resolve this issue.
CONCLUSIONS
1. Rhesus monkeys displayed a relatively consistent pattern of interference
behavior, both within and across ecological settings. Females were particularly
consistent in aiding victims of aggression and relatives, while males were most
consistent in aiding older animals and in aiding when dominant to the target.
2. Compound-dwelling rhesus males were much more likely to aid aggressors
than were their free-ranging counterparts. This appeared to be the most significant
effect of increased confinement on interference behavior.
3. Rhesus monkey females differed from males in that they were more likely
than males to aid relatives and juveniles, to aid against target animals dominant to
Fight Interference in Rhesus Macaques I 297
themselves, and, overall, to aid victims. However, when not aiding relatives, females
tended to be more male-like in their interference patterns.
4. Rhesus monkey males interfered at little risk to themselves, and may have
interfered in a way (eg, “scapegoating”) which reduced social tension among
themselves.
5. There was little evidence to support the existence of a unique “control” role
for dominant rhesus monkey males. These males either interfered in a way which
exacerbated rather than controlled aggression, or they interfered in a manner
similar to that of other males or females.
ACKNOWLEDGMENTS
This work was supported in part by grants from the NSF (6s 2377), NIH (HL
R01 26561, IIL 14164, RR 00165), NIMH (MH-204831, and the University of Alabama in Birmingham (faculty research grant to JRK).
REFERENCES
Altmann, J. Observational study of behavior:
Sampling methods. BEHAVIOUR 48:l-41,
1974.
Bernstein, IS.; Sharpe, L.G. Social roles in a
rhesus monkey group. BEHAVIOUR 26: 91104, 1966.
Bernstein, I.S.; Ehardt, C.L. Agonistic aiding: Kinship, rank, age, and sex influences.
AMERICAN JOURNAL OF PRIMATOLOGY 8:37-52,1985.
Chikazawa, D.; Gordon, T.P.; Bean, C.A.;
Bernstein, IS. Mother-daughter reversals
in rhesus monkeys (Macaca mulatta). PRIMATES 20:301-304, 1979.
Datta, S.B. Patterns of agonistic interference. Pp 289-297 in PRIMATE SOCIAL
RELATIONSHIPS: AN INTEGRATED APPROACH. R.A. Hinde, ed. Sunderland,
Massachusetts, Sinauer Associates, 1983.
de Waal, F.B.:M. Organization of agonistic
relations within two captive groups of Java
monkeys (2Clacaca fascicularis). ZEITSCHRIFT :FUR TIERPSYCHOLOGIE
44:225-282, 1977.
de Waal, F.B.M. Sex differences in the formation of co,alitions among chimpanzees.
ETHOLOGY .AND SOCIOBIOLOGY5:239255, 1984.
Erwin, J. Agression in captive macaques: Interaction of social and spatial factors. Pp
139-171 in CAPTIVITY AND BEHAVIOR:
PRIMATES IN BREEDING COLONIES,
LABORATOFLIES, AND ZOOS. J. Erwin,
T.L. Maple, G. Mitchell, eds. New York, Van
Nostrand Reinhold, 1979.
Gartlan, J.S.; Brain, C.K. Ecology and social
variability in Cercopithecus aethiops and C.
mitis. Pp 253--292 in PRIMATES, STUDIES
IN ADAPTATION AND VARIABILITY.
P.C. Jay, ed. New York, Holt, Rinehart 8z
Winston, 1968.
Hausfater, G. Dominance and reproduction
in baboons (Papio cynocephalus): A quantitative analysis. CONTRIBUTIONS TO
PRIMATOLOGY, No. 7. Basel, S. Karger,
1975.
Kaplan, J. Patterns of fight interference in
rhesus monkeys. AMERICAN JOURNAL
OF PHYSICAL ANTHROPOLOGY 41:487,
1974.
Kaplan, J.R. Patterns of Interference and the
Control of Aggression in a Group of Freeranging Rhesus Monkeys. Ph.D. Dissertation, University of Michigan, Ann Arbor,
Michigan, UNIVERSITY MICROFILMS,
1976.
Kaplan, J.R. Patterns of fight interference in
free-ranging rhesus monkeys. AMERICAN
JOURNAL OF PHYSICAL ANTHROPOLOGY 47:279-287,1977.
KaDlan. J.R. Fight interference and altruism
i n rhesus monkeys. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY
491241-249, 1978.
Kaplan, J.R.; Chikazawa, D. Comparison of
compound and free-ranging rhesus monkeys. AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY. 48:410,1978.
Kaplan, J.R.; Manuck, S.B. Patterns of fight
interference in one-male harem groups of
cynomolgus macaques. AMERICAN JOURNAL OF PRIMATOLOGY 8:346,1985.
Kaufmann, J.H. Social relations of adult
males in a free-ranging band of rhesus monkeys. Pp 73-98 in SOCIAL COMMUNICATION AMONG PRIMATES, S.A. Altmann.
ed. Chicago University Press, Chicago, 1967:
Kirk. R.E. EXPERIMENTAL DESIGN:
PROCEDURES FOR THE BEHAVIORAL
SCIENCES. Belmont, California, Brooks/
Cole, 1968.
Kurland, J.A. Kin selection in the Japanese
monkey. CONTRIBUTIONS TO PRIMATOLOGY No. 12. Basel, S. Karger, 1977.
Massey, A. Agonistic aids and kinship in a
group of pigtail macaques. BEHAVIORAL
ECOLOGY AND SOCIOBIOLOGY 2:31-40,
1977.
Nishida, T. Alpha status and agonistic alliance in wild chimpanzees (Pan troglodytes
schweinfurthii). PRIMATES 24:318-336,
1983.
298 I Kaplan, Chikazawa, and Manuck
Oswald, M.; Erwin, J. Control of intragroup
aggression by male pigtail monkeys (Macaca nernestrina). NATURE (LONDON)
2621656-687,1976.
Packer, C. Reciprocal altruism in Pupio unubis. NATURE (LONDON) 265:441-443,
1977.
Rowell, T. THE SOCIAL BEHAVIOR OF
MONKEYS. Baltimore, Penguin Books,
1972.
Sade, D.S. Determinants of dominance in a
group of free-ranging rhesus monkeys. Pp
99-114 in SOCIAL COMMUNICATION
AMONG PRIMATES. S.A. Altmann, ed.
Chicago, University of Chicago Press, 1967.
Sade, D.S. A longitudinal study of social behavior in rhesus monkeys. Pp 377-398 i n
FUNCTIONAL AND EVOLUTIONARY
BIOLOGY OF PRIMATES. R. Tuttle, ed.
Chicago, Aldine Atherton, 1972.
Sade, D.S.; Cushing P.; Cushing, K.; Dunaif,
A.; Figueroa, A.; Kaplan, J.R.; Lauer, C.;
Rhodes, D.; Schneider, J. Population dynamics in relation to social structure on
Cay0 Santiago. YEARBOOK OF PHYSICAL ANTHROPOLOGY 20:251-262,1977.
Tokuda, K.; Jensen, G. The leader’s role in
controlling aggressive behavior. PRIMATES 9:319-322,1968.
Trivers, R.L. The evolution of reciprocal altruism. QUARTERLY REVIEW OF BIOLOGY 46:35-57,1971.
Watanabe, K. Alliance formation in a freeranging troop of Japanese macaques. PRIMATES 20:459-474,1979.
West-Eberhard, M.J. The evolution of social
behavior by kin selection. QUARTERLY
REVIEW OF BIOLOGY 5O:l-33.1975.
Документ
Категория
Без категории
Просмотров
3
Размер файла
863 Кб
Теги
fight, compounds, interferenz, macaque, free, aspects, rhesus, dwelling, mulatta, macaca, ranging
1/--страниц
Пожаловаться на содержимое документа