honess 2006
TRANSCRIPT
8/3/2019 Honess 2006
http://slidepdf.com/reader/full/honess-2006 1/14
Anita. Behav., 199 1,41 , 121 134
Ag gression in interaction s of imm ature rhesus monkeys: components, con tex t
and relation to affiliation lev els
M A G D A L E N A J A N U S *
S u b - d e p a r t m e n t o f A n i m a l B e h a vi o u r, C a m b r i d g e U n i ve rs it y, M a d i n g l e y , C a m b r id g e C B 3 8 A A , U . K .
(Received 16 Februa ry 1990; initial acceptance 30 M arch 1990;
final acceptance 28 June 1990; M S. number 3535)
Abs t rac t . A g o n i s t i c i n t er a c t io n s o f i m m a t u r e r h e s u s m o n k e y s , M a c a c a m u l a t t a , were s t u d i ed o v e r two
seaso n s . Th e h y p o th es i s t e s t ed co n ce rn ed t h e l ev e l s an d t y p e o f ag g re ss io n b e tween mo n k ey s sh o win g
vario us degrees o f a ff i lia t ion : s t rong ly affi l ia ted par tne rs w ere expected to sh ow h igh er overa l l l eve ls , and
d i f fe ren t t y p es , o f ag g re ss io n t h an t h e wea k ly a f f il ia t ed p a r tn e rs . Pa i r s o f mo n k ey s w ere d iv id ed i n to s i b li n g s
( t h o se wi th t h e sam e mo th e r ) an d n o n -s ib l i n g s ( t h o se wi th d if fe ren t mo th e rs ) . Th e l a t t e r g ro u p was fu r t h e rd iv id ed i n to p ee rs ( same-ag e p a r tn e rs ) an d n o n -p ee rs (d i f fe ren t -ag e p a r tn e rs ) . I t i s k n o wn th a t y o u n g
s ib li n g s sh o w h ig h e r d eg rees o f a f f il i at i o n t h an n o n -s ib l i n g s an d t h a t p ee rs a re m o re a ff ili at ed t h an n o n -p ee rs .
F i r s t , t h e l ev e ls o f ag g re ss io n ex p re ssed b y m o n k ey s were e s t ab li sh ed . D y ad s o f s i b li n g s an d p ee rs sh o w ed
m o r e a g g r e s s io n t h a n d y a d s o f n o n - p e e r s. T h e n , a g g r e s s io n c o m p o n e n t s i n t e r m s o f s tr e n g t h a n d r e s p o n s iv e -
n ess , an d t h e co n t ex t o fag o n i s t i c ep i so d es b e tween m o n k ey s a f f i li a ted t o d i f fe ren t d egrees , we re in v es t i g at ed .
S t ro n g ly a ff il ia ted d y ad s sh o wed l es s o f t h e sev e re ty p es o f ag g re ss io n t h an weak ly a f fi li a ted o n es . B o th
s ib l i n g s an d p ee rs sh o wed mo re rec ip ro ca l ag g re ss io n t h an n o n -p ee rs . S ib l i n g s h ad mo re co n f l i c t s t h an
n o n -s ib l i n g s i n t h e co n t ex t s o f g ro o m in g an d p u n i sh m en t , b u t a h ig h e r p ro p o r t i o n o f sev e re co n f l i c ts o f
n o n -s ib l i n g s t h an o f s i bl in g s h ap p en ed i n a feed in g co n t ex t . Th u s a f f i l ia t io n seems t o h av e im p o r t an t l in k s
wi th the levels and c harac ter i s t ics o f agonis t ic in terac t ions . I t i s sugge sted tha t su ch d i fferences are a d i rec t
co n seq u e n ce o f d if fe ren t q u a l it ie s o f re l a ti o n sh ip b e tween s t ro n g ly an d weak ly a f fi li a ted d y ad s .
L iv in g c lo se t o g e th e r i n so c i a l g ro u p s , p r ima te s
s u c h a s m a c a q u e s a n d b a b o o n s a r e c o n s t a n t ly i n te r -
ac t i n g wi th t h e i r f e l lo w g ro u p -m em b ers . So c i a l l if e
i s u su a l l y co n s id e red t o b e ad v an t ag eo u s fo r
m o n k e y s , f o r e x a m p l e b y r e d u c i n g t h e r i s k o f p r e d -
a t i o n ( C h e n e y & W r a n g h a m 1 98 7) , o r b y p r o v i d i n g
p a r tn e rs f o r g ro o m in g (e .g . Sau n d e rs 1 9 87 ). Ho w -
ev e r , wh en re so u rces v i t a l fo r su ccess fu l r ep ro -
d u c t i o n a re sca rce , t h e an ima l s h av e t o co m p e te fo r
t h em wi th t h e i r c l o se n e ig h b o u rs (Cro o k 1 9 7 0 ) .
Th u s , t h e sam e in d iv id u a l s m ay a t t imes b e f r i en d ly
to each o th e r , an d a t o th e rs , ag g re ss iv e .
Th e re a re co n f l i c t i n g rep o r t s a s t o t h e d i s t r i -
b u t i o n o f a g g re s s io n i n p r im a t e g r o u p s . W h i le s o m e
s tu d i e s h av e sh o wn th a t t h e re i s l e s s ag g re ss io n
a m o n g r e l a t i v e s t h a n a m o n g u n r e l a t e d a n i m a l s
(e.g. vervets, Cercopithecus ae thiops: Lee 1987),
o t h e r s h a v e d e m o n s t r a t e d m o r e a g g r e s s i o n a m o n g
re la t ives ( rhesus , M a c a c a m u l a t t a : Bern s t e in &
*Present address: The Psychiatric Research Unit, TheHospital for Sic k Children , 555 U niversi ty A venue,Toro nto, Ontario M5G 1X8, Canada.
E h a r d t 1 98 6; J a p a n e s e m o n k e y s , M a c a c a f u s c a t a :
Gl ick e t a l . 1 9 8 6 ) . On t h e o th e r h an d , a l t h o u g h
fac to rs t h a t i n fl u en ce ag g re ss io n su ch a s ag e an d sex
(D i t tus 1977; E ato n e t a l. 1981; Y ou ng e t a l . 1982) ,
sea so n (Wi l so n & B o e lk in s 1 9 7 0; Dr i ck am er 1 9 75 ;
Eaton e t a l . 1981; Teas e t a l . 1982) or hormonal
s t a t e (Mich ae l & Zu mp e 1 9 7 0 ; Lo y 1 9 7 1 ; Dix so n
1980) have of ten been s tud ied , the k insh ip effec t
has of ten bee n neglec ted . Ei ther re la t ives have been
reg a rd ed sep a ra t e ly f ro m n o n - re l a ti v e s (e.g . Da t t a
1 9 83 a , b ) o r k in re l a t i o n s h av e n o t b een k n o w n
sufficiently (e.g. D it tu s 1977; E at on e t al . 1981; Te as
et al. 1982).
Ev en w i th in o n e sp ec ie s, t h e rh esu s mo n k ey , t h e re
a r e r e p o r t s o f b o t h m o r e a n d le ss a g g r e s s io n b e tw e e n
s t ro n g ly a f fi li a ted p a r tn e rs t h an b e tween t h o se w i th
weak aff i l ia t ive bonds . Bernste in & Ehard t (1986)
h a v e s h o w n t h a t y o u n g r h es u s m o n k e y s d i r e c t sig -
n i f i can t l y mo re ag g re ss io n t o ward s , an d rece iv e
m o r e a g g r e s s i o n f r o m , k i n t h a n n o n - k i n . C o l v i n& Ti s s i e r (1 9 8 5 ) , h o wev e r , fo u n d t h a t immatu re
rh esu s ma le s were l e s s ag g re ss iv e b o th t o ward s
s ib l i n g s an d u n re l a t ed ma le p ee rs wi th wh o m th ey
0003-3472/91/010121 + 14 $03.00/0 9 1991 The A ssociation for the Study of Animal Behaviour
121
8/3/2019 Honess 2006
http://slidepdf.com/reader/full/honess-2006 2/14
12 2
h a d s t r o n g a f f i li a t iv e r e l a t i o n s h i p s t h a n t o w a r d s
l e ss a f f i l i a ted m a le p ee r s .
T h e e v i d e n c e f o r s e x d if f e re n c e s i n t h e a m o u n t o f
a g g r e s s i o n i n m a n y p r i m a t e s p e c i e s i s a l s o c o n f li c t -
i n g ( r e v i ew e d i n S m u t s 1 98 7) . I t h a s b e e n h y p o t h e -
s i zed th a t t h e sp ec ie s d i f f e r en ces in ag g r ess io n
d e p e n d o n w h i c h s e x e m i g r a t e s f r o m t h e n a t a l g r o u p .
T h e m e m b e r s o f t h e n o n - e m i g r a t i n g s e x d e v e l o p
m u c h s t r o n g e r so c i a l b o n d s w i t h e a c h o t h e r t h a n t h e
m e m b e r s o f th e e m i g r a t in g s ex . A s a n i m a l s h a v i n g
s t r o n g a f f il i a ti v e b o n d s a r e q u i t e o f t e n a l s o m o r e
a g g r e s s i v e t o e a c h o t h e r t h a n l e s s a f f il i a te d d y a d s
( e .g . W a l t e r s 1 98 6), t h e r e m a y a l s o b e m o r e a g g r e s -
s i o n b e t w e e n m e m b e r s o f t h e n o n - e m i g r a t i n g s ex .
A l t e r n a t i v e ly , in f e m a l e - b o n d e d p r i m a t e s o c ie t ie s
l i k e t h o s e o f m a c a q u e s , a n i n f a n t f e m a l e i s a p o t e n -
t i a l f u t u r e c o m p e t i t o r f o r a d u l t f e m a l e s , w h e r e a s
i n f a n t m a l e s w i ll l e a v e t h e i r n a t a l g r o u p w h e n t h e y
m a t u r e . T h i s h a s b e e n u s e d t o e x p l a i n w h y a d u l t
f e m a l es d i r e c t m o r e a g g r e s si o n t o w a r d s f e m a l e t h a n
t o w a r d s m a l e i n f a n t s ( S i l k et a l . 1 9 81 )
I n v i e w o f t h e a b o v e e v i d e n c e , i t i s p o s s i b l e t h a t
l o o k i n g a t t h e a g o n i s t i c i n t e r a c t io n s i n m o r e d e t a i l,
t h a t i s, c o n s i d e r i n g t h e k i n d o f a g g r e s s i o n e x p r e s s e d
( e . g . B e r n s t e i n & E h a r d t 1 9 8 5 ) a n d t h e c i r c u m -
s t a n c e s a n d c o n t e x t i n v o l v e d ( e .g . P e r e i r a 1 98 8a ),
m a y t h r o w f u r th e r l i g h t o n q u e s t io n s a b o u t t h e d i f -
f e r e n ce s i n a g o n i s t i c i n t e r a c t i o n s b e t w e e n s t r o n g l y
a n d w e a k l y a f fi l ia t e d p a r t n e r s . I n p a r t i c u l a r , i t
m a y b e i m p o r t a n t t o f i n d o u t w h e t h e r c l o s e a f f i l i -
a t i o n l e a d s t o a h i g h e r i n c i d e n c e o f a g g r e s s i o n , b u t
t h a t e i t h e r s u c h a g g r e s s i o n i s n o t s e v e r e , o r t h a t
p o t e n t i a l l y c o m p e t i t i v e s i t u a t i o n s i n f e e d i n g t im e ,
f o r e x a m p l e , a r e r e s o l v e d w i t h o u t u s i n g m u c h
a g g r e s s i o n .
A m o n g i m m a t u r e r h es u s m o n k e y s p a i r s o f s ib -
l i n g s a r e t h e m o s t a f f il i a te d d y a d s , w i t h p e e r s
( n o n - s ib l i n g m o n k e y s b o r n i n t h e s a m e y e a r ) t a k i n gs e c o n d p l a c e, a n d n o n - s i b l in g n o n - p e e r d y a d s b e i n g
t h e l e a s t a f f il i a te d o f th e t h r e e g r o u p s ( J a n u s 1 9 89 a ,
b ) . I n t h i s p a p e r , I c o n s i d e r i n d e t a i l a g o n i s t i c i n t e r -
a c t i o n s b e t w e e n s i b l in g , p e e r a n d n o n - s i b l i n g n o n -
p e e r d y a d s o f y o u n g r h e s u s m o n k e y s . A s i n d i c a t e d
a b o v e , t h e q u e s t i o n s i n v e s t i g a t e d c o n c e r n d i f f e r-
e n c e s i n t h e le v e ls , c o m p o n e n t s a n d c o n t e x t o f
a g g r e s s i o n b e t w e e n d y a d s a f f i l ia t e d t o d i f f e ri n g
d e g r e e s . T h e r e f o r e , f i r st , I e x a m i n e t h e a m o u n t o f
a g g r e s s i o n in s i b l in g , p e e r a n d n o n - p e e r d y a d s a n d
e s t a b l i s h t h e r e l a t i o n s b e t w e e n t h e a f f i li a t io n a n da g g r e s s i o n l e ve l s i n d y a d s . S e c o n d , I e x a m i n e t h e
c o m p o n e n t s o f a g g r e s si o n , w i th t h e h y p o t h e s i s
t h a t t h e r e i s l e s s s t r o n g a g g r e s s i o n i n a f f i l i a t e d
Animal Behaviour, 41, 1
Table I . The composition of the study sample
1986-1987 1987-1988
N 20 20Males 7 8Fem ales 13 12Sibling dya ds 13 11All non-sibling dyad s 30 36Peer dyads 9 10No n-peer dyad s 21 26Nu mb er of focal hours
of observat ion perdya d 35 38.5
d y a d s . T h i r d , I te s t t h e h y p o t h e s i s t h a t c o n t e x t s o fa g g r e s s i o n d i f f e r b e t w e e n s i b l i n g a n d n o n - s i b l i n g
d y a d s . S e x a n d a g e d i ff e r e n ce s a r e r e p o r t e d , w h e r e
a p p r o p r i a t e .
M E T H O D S
The Monkeys
I s t u d i e d a c a p t i v e c o l o n y o f r h es u s m a c a q u e s i n
M a d i n g l e y a t C a m b r i d g e U n i v e r s i ty . T h e c o l o n y
h o u s e s s i x s o c i a l g r o u p s , e a c h c o n s i s t i n g o f o n e
a d u l t m a l e , t w o t o s i x a d u l t f e m a l e s a n d t h e i r s u b -
a d u l t , j u v e n i l e a n d i n f a n t o f f s p r i n g . E a c h g r o u p
h a d a n o u t d o o r w i re m e s h e n c l o su r e , l ea d i n g i n t o
a s m a l l e r h e a t e d i n d o o r r o o m . T h e o u t d o o r p e n s
wer e 7 - 8 m lo n g , 2 "5 m wid e an d 2 .2 m h ig h a t t h e
i n d o o r r o o m e n d , r i s i n g t o 3 . 9 m a t t h e o t h e r e n d .
T h e f l o o r a r e a o f e a c h o u t d o o r p e n w a s 1 8.2 m 2 .
T h e s t u d y p e r i o d l a s t e d f r o m N o v e m b e r 1 9 8 6 t o
S e p t e m b e r 1 9 88 , d i v i d e d i n t o t w o s e a s o n s . E a c h
s e a s o n s t a r t e d a t , o r j u s t b e f o r e , t h e o n s e t o f
t h e b r e e d i n g s e a s o n , a n d f i n i sh e d w i t h t h e e n d o f
t h e b i r t h s e a s o n . R h e s u s m o n k e y s a r e s e a s o n a lb r e e d e r s , w i t h c l e a r -c u t m a t i n g a n d b i r t h s e a s o n s
( e .g . A n d e r s o n & S i m p s o n 1 97 9) . F o r t h e p u r p o s e
o f m y o b s e r v a t i o n s , t h e f i rs t s e a s o n l a s t e d f r o m
18 N o v e m b e r 1 98 6 u n ti l 3 S e p t e m b e r 1 9 87 ( ' 1 9 8 6 -
1 9 8 7 ' ) . T h e s e c o n d o n e l a s t e d f r o m 4 S e p t e m b e r
1 98 7 u n t i l 2 9 Sep tem b er 1 98 8 ( ' 1 9 8 7 - 1 9 8 8 ' ) .
M y s u b j e c t s w e r e 28 y o u n g m o n k e y s , l i v in g i n
f o u r g r o u p s . I n e a c h s e a s o n I o b s e r v e d 2 0 m o n k e y s
( T a b l e I ) . O u t o f t h e 2 8 s u b j e c t s, 12 w e r e s t u d i e d
t h r o u g h o u t b o t h s e a s o ns , a n d 16 f o r o n l y o n e.
E i g h t o f t h e l a t t e r g r o u p w e r e d r o p p e d a f t e r t h e f ir s ts e a s o n b e c a u s e a t t h e a g e o f a b o u t 3"5 y e a r s t h e y
a p p r o a c h e d s e x u a l m a t u r i t y ( se e D r i c k a m e r 1 97 4;
M e l n i c k & P e a r l 1 98 7). I n t h e s e c o n d s e a s o n e i g h t
8/3/2019 Honess 2006
http://slidepdf.com/reader/full/honess-2006 3/14
Janus: Aggression in young rhesus monkeys 123
n e w i n fa n t s w e r e o b s e r v e d f r o m t h e a g e o f a b o u t 4
m o n t h s . B e c a u se o f t h i s d i s c re p a n c y in t h e n u m b e r
o f s ea s o n s m o n k e y s w e r e o b s e rv e d , d a t a f r o m e a c h
s e a s on w e r e n o t c o m b i n e d b u t a n a l y s e d s e p a r a te l y .
T h e m o n k e y s w e r e c l a s s if i e d b y a g e a s I n f a n t s ,
Y o u n g J u v e n i l e s a n d O l d J u v e n i l e s , u s i n g a m o d i -
f ie d v e r s i o n o f E h a r d t & B e r n s t e i n ' s ( 1 98 7 ) c r i t e ri a :
I n f a n t s , u n t i l 1 . 5 y e a r s o f a g e ; Y o u n g J u v e n i le s ,
b e tween 1 .5 an d 2 " 5 y ea r s ; an d Old Ju v en i l e s ,
b e tw een 2 .5 an d 3 -5 y ea r s .
P a i r s o f m o n k e y s ( d y a d s ) w e re d i v i d e d i n t o
t h r e e c a t e g o r i e s : s i b l in g s , t h o s e w h o h a d t h e s a m e
m o t h e r ; p e e r s , th o s e w h o h a d d i f f e r e n t m o t h e r s b u t
w e r e b o r n i n t h e s a m e y e a r ; a n d n o n - p e e r s , t h o s e
w h o h a d d i ff e re n t m o t h e r s a n d w e r e b o r n i n d if -
f e r e n t y e a r s . T h e t w o l a t t e r g r o u p s ( p e e r s a n d
n o n - p e e rs ) a r e s o m e t i m e s j o i n t l y d e s c r ib e d a s n o n -
s i b l i n g s . T h e m a x i m u m a g e d i f f e r e n c e b e t w e e n
s t u d y s u b j e c t s w a s 2 y e a r s . T h e 2 0 s u b j e c t s o f t h e
f i r s t seas o n f o r m ed 1 3 s ib l in g , 9 p ee r an d 2 1 n o n -
p e e r d y a d s , t h e 2 0 s u b j e c t s o f t h e s e c o n d s e a s o n
f o r m e d 11 s i b li n g , 10 p e e r a n d 2 6 n o n - p e e r d y a d s .
T w o a d d i t i o n a l c a t e g o ri e s o f ' r e c i p r o c a l ' a n d ' n o n -
r e c i p r o c a l ' p a r t n e r s w e r e d i s t i n g u is h e d a m o n g a l l
d y a d s . D y a d s o f m o n k e y s w h o w e r e e ac h o t h e r ' s
m o s t o r s e c o n d m o s t f r e q u e n t p a r t n e r s i n p l a y ,
g r o o m i n g o r p r o x i m i t y , w e r e c l a s s if i e d a s ' r e c i p r o -
c a l p a r t n e r s ' i n o n e o r m o r e o f t h o s e t h r e e a f f il i a ti v e
b e h a v i o u r p a t t e r n s ( s e e J a n u s 1 98 9b f o r d e t a il s ) .
T h e f a m i l y r a n k o f a m o n k e y w a s i d e n t i fi e d a s l o w
i f i t s m o t h e r ' s r a n k i n t h e a d u l t - f e m a l e s ' h i e r a r c h y
w a s t h i r d o r l o w e r , a n d a s h i g h i f i ts m o t h e r w a s t h e
a - f e m a l e . F o r c l a r i t y , o f f s p r i n g o f s e c o n d - r a n k i n g
m o t h e r s w e r e o m i t t e d f r o m t h e c l a s s if i ca t io n .
Sampling and Behaviour
I s a m p l e d t h e 2 0 s u b j e c t s i n e a c h s e a s o n o n a f o c a la n i m a l b a s i s ( A l t m a n n 1 97 4). I n e a c h s e a s o n I o b -
s e r v e d a f o c a l m o n k e y f o r a t l e a s t 7 0 1 5 - m i n o b s e r -
v a t i o n s w h i c h w e r e g r o u p e d i n t o 2 - m o n t h b l o c k s.
D u r i n g a f o c a l o b s e r v a t i o n , a l l s o c i a l i n t e r a c t i o n s
i n v o l v i n g t h e s a m p l e d m o n k e y w e r e r e c o r d e d ,
t o g e t h e r w i t h t h e i d e n t i t y o f t h e i n t e r a c t a n t s ( f o r
d e ta i l s see Jan u s 1 9 89 b ).
A g g r e s s i o n w a s r e c o r d e d i f a m o n k e y a t t a c k e d ,
t h r e a t e n e d , h i t , g r a b b e d , c h a s e d o r d i s p l a c e d
a n o t h e r m o n k e y ( a g gr e s si v e b e h a v i o u r ) o r a v o i d e d ,
f e a r - g ri n n e d ( b a r e -t e e t h d i s p l a y , d e W a a l & L u t t r e t l1 98 5), s c r e a m e d o r j e r k e d a t a n o t h e r m o n k e y ( s u b -
m i s s i v e b e h a v i o u r ) . F o r e a c h a g o n i s t i c i n t e r a c t i o n
i n v o l v i n g a f o c a l m o n k e y , I r e c o r d e d t h e k i n d s o f
a g o n i s ti c b e h a v i o u r b y t h e f o c a l i n d iv i d u a l a n d i ts
p a r t n e r o r p a r t n e r s , a n d t h e i r i d e n t it i e s . I f k n o w n ,
t h e c o n t e x t a n d / o r t h e r e a s o n f o r t h e c o n f l i c t , a s
w e l l a s t h e n a m e s o f m o n k e y s w h o j o i n e d i n , w e r e
r e c o r d e d . I f 1 5 s o r m o r e e l a p s e d b e t w e e n a g o n i s t i c
e p i s o d e s , t h e y w e r e s c o r e d a s t w o i n t e r a c t i o n s .
A g o n i s t i c i n t e ra c t i o n s w e r e p o s t h o c d i v i d e d i n to
S t r o n g A g g r e s s i o n , M i l d A g g r e s s i o n a n d R e c i p r o -
c a l A g g r e s s i o n u s i n g t h e f o l l o w i n g d e f i n i t i o n s .
S t r o n g A g g r e s s io n : a n y o f t h e b e h a v i o u r d e f i n e d
p r e v i o u s l y a s ' a g g r e s s i v e ' a c c o m p a n i e d b y a b i te
a n d / o r f o l lo w e d b y a n e v a s iv e a c t io n b y t h e t a r -
g e t m o n k e y . M i l d A g g r e s s i o n : a n y a g g r e s s i o n o r
s u b m i s s i v e b e h a v i o u r w i t h o u t b o d y c o n t a c t a n d /
o r l a c k i n g a r e s p o ns e f r o m t h e t a r g e t m o n k e y .
R e c i p r o c a l A g g r e s s i o n : a n y k i n d o f a g g r e s s i v e
b e h a v i o u r t o w h i c h t h e t a r g e t m o n k e y r e s p o n d e d
w i t h a g g r e s s i o n .
I n a d l i b i tu m r e c o r d s o f a g o n i s t i c in t e r a c t io n s
I a l w a y s r e c o r d e d t h e i d e n t i t y o f th e m o n k e y s i n-
v o l v e d , a n y t h i r d p a r t i e s a n d t h e k i n d o f a g g r e s s i o n .
W h e n k n o w n , t h e c o n t e x t w a s a l so r e c o rd e d . I n t h i s
p a p e r I i n c l u d e o n l y t h e a d l i b i t u m d a t a r e c o r d e d
d u r i n g f o c a l o b s e r v a t io n s o n o t h e r m o n k e y s i n t h e
s a m e p e n . T h e r e f o r e , t h e t o t a l n u m b e r o f h o u r s i n
w h i c h t h e s e e p i s o d e s w e r e o b s e r v e d w e r e b e t w e e n
5 2 .5 an d 1 0 5 in 1 9 8 6 - 1 9 8 7 , an d b e tween 3 8 .5 an d
134.75 in 1987 -1988.
Derived Measure s
A s m e n t i o n e d a b o v e I c o n s i d e r h e r e o n l y a g o n -
i s t ic i n t e r a c t i o n s t h a t i n v o l v e d i m m a t u r e a n i m a l s .
T h e m e a s u r e s o f a g g r e s s i o n I u s e d a r e a s f o l l o w s .
A g g r e s s i o n r a te : t h e n u m b e r o f a g o n i s t i c i n t e ra c -
t i on s p e r h o f o b s e r v a t i o n ( f r o m f o ca l o b s e r v a t i o n s
o n l y ) . A l l a g g r e s s i o n : th e s u m o f a l l a g o n i s t i c i n t e r -
a c t i o n s in w h i c h a m o n k e y w a s i n v o l v ed ( fo c a l a n da d l i b i t u m c o m b i n e d ) . S t r o n g A g g r e s i o n : a g o n is t i c
i n t e r a c t i o n s c l a s s i fi e d a s ' s t r o n g ' a c c o r d i n g t o
t h e d e f i n i t io n s a b o v e . M i l d A g g r e s s i o n : a g o n i s t i c
i n t e r a c t i o n s c l a s s if i e d a s ' m i l d ' a c c o r d i n g t o t h e
d e f i n i t io n s a b o v e . R e c i p r o c a l A g g r e s s i o n : a g o n i s t i c
i n t e r a c t i o n s c l a s s i fi e d a s ' r e c i p r o c a l ' a c c o r d i n g t o
t h e d e fi n i ti o n s a b o v e . S t r o n g , M i l d a n d R e c i p r o c a l
A g g r e s s i o n al w a y s a d d e d u p t o t h e ' A l l a g g r e s s io n '
m e a s u r e .
I n c o m p a r i s o n s b e t w e e n i n d i v i d u a l s t h e d a t a
f r o m b o t h f o c a l a n d a d l i b i t u m o b s e r v a t i o n s w e reu s e d . T h e a g o n i s t i c i n t e r a c t i o n s i n w h i c h a p a r -
t i c u l a r m o n k e y w a s i n v o l v e d w e r e d i v i d e d i n t o
a g g r e s s i o n g i v e n a n d a g g r e s s i o n r e c e i v e d . F o r
8/3/2019 Honess 2006
http://slidepdf.com/reader/full/honess-2006 5/14
J a n u s : A g g r e s s i o n i n y o u n g r h e s u s m o n k e y s
However, when the analysis was done separately
for siblings and non-siblings, he correlations were
weaker (siblings: 1986-1987, rs=0'242, P=0.2;
1987-1988, r s = 0"2t4, P = 0'2; non-s ibl ings: 1986-
1987, rs=0,184, P=0-16; 1987-1988, rs=0"305,
P=0"03). One possible explanation is that the
sample size of either siblings and non-sibl ingsalone
was not large enough to allow correlations to be
statistically significant. On the other hand, a more
plausible explanation for the significant (and
higher) correlation on the combined sample might
be that in siblings as a group b oth aggression and
proximity values were high and in non-sibl ingsas a
group both these values were low, which may have
enhanced the correlation when the two groups were
considered together.
Indiv idual Di fferenc es
Individuals directed more aggression to their
siblings than to non-siblings in both seasons
(Wilcoxon matched-pair signed-ranks test, one-
tailed probabi lities , 1986-1987: Z = - 1-89, N = 17,
P<0 .02 ; 1987-1988: Z= -l . 73 , N = 14, P<0.0 4).
This was tested by matching average scores of
aggressive behaviour towards siblings with those
towards non-siblings for each individual (seeMethods).
A g e a n d s e x d i ff e r en c e s
The levels of aggression in which individual
monkeys were involved differed according to their
age only in the second season (one-way ANOVA,
Infants versus Young Juveniles versus Old Juv-
eniles; 1986-1987, F=0.097, df =2 , NS; 1987-1988,
F=3-73, d f = 2 , P=0"045), but even then the
Stud ent- Newma n-Ke ul est did not show a differ-
ence between any two groups at et = 0'05: However,in both seasons the differences between the three
ages in propor tions of aggression given and received
were significant, with the youngest animals giving
the least but receiving the most aggression
(Kruska l-Wall is ANOVA, 1986-1987, N x (In-
fants) = 6, N z (Young Juveniles) = 6, N 3 (Old Juven-
iles)=8, aggression given ~2=8.41, P<0-01,
aggression received ~2 = 8.41, P<0 .0 1; 1987-1988,
N 1 (Infants) = 8, N 2 (Young Juveniles) = 6, N 3 (Old
Juveni les) = 6, aggression given Z2 = 8' 79, P < 0.01,
aggression received ~z = 8-79, P < 0.01).Aggression given versus aggress ion received were
tested separately for Infants, Youn g and Old Juv-
eniles. Among Infan ts, the percentage of aggression
125
I-0
2 "~ 0-8
?'//,,g ' - V//,,
2 ~ . I / / / /'4 " / / "
0 , 2 ! ; " "
co
0"0Infant Young Juvenile Old Juvenile
Figure 2. Median proportions of aggression given([]) andreceived ([]) out of all agonistic interactions in whichmonkeys of various ages were involved. N Infants = 14, NYoung Juveniles= 12, N Old Juveniles= 14. Sample com-
bined from both seasons, as no monkey could be in thesame age category over both seasons. Bars representinterquartile intervals.
received was significantly higher th an that given
(Wilcoxon matched-pai r test, Z= - 3.23, N= 14,
P<0.01). Among Young Juveniles there was
no difference between the two percentages (Z=
- 0.16, N = 12, P = 0'8). Among Old Juveniles per-
centage of aggression given was higher t han that
received (Z = -2 .1, N= 14, P < 0.05; Fig. 2).
There were no differences in the involvem ent inagonistic interaction between immature males and
females (1986 1987: t= -0 .7 8, d f = 18, NS; 1987-
1988, t = -- 1"46, NS). Nor were there any significant
sex differences in the amo unt of aggression given or
received.
F a m i l y r a n k
In both seasons, young monkeys coming from
low-ranking families received more aggression
than those coming from high-ranking families
(Ma nn- Whi tne y U-test, 1986-1987: U= 3, N I =11, N2= 5, P <0. 01; 1987-1988: U = I, N~=8 ,
N z = 5, P<0- 01). The monkeys from low-ranking
families also received more aggression than they
gave to other young monkeys (Wilcoxon test, one-
tailed probabilities, 1986-1987: Z = - 1.75, N=5 ,
P<0. 04; 1987-1988: Z--- -2- 02, N= 5, P<0.0 2).
The monkeys from high-ranking families, in con-
trast, gave more aggression than they received
(Wilcoxon test, one-tailed probabilities, 1986-
1987: Z= -1 .9 6 , N= l l, P<0.03 ; 1987-1988:
Z = -- 1-82, N= 8, P < 0.03).Interestingly, there was a sex difference in the
rates of aggression received by low-rank ingInfants.
Low-ranking females were more likely to receive
8/3/2019 Honess 2006
http://slidepdf.com/reader/full/honess-2006 6/14
12 6 Animal Behaviour, 41, 1
Table I I . Co mp onen ts o f aggression in s ib l ing , peer and non-pe er dyads
1986-1987
A g g res si o n M ed i an N u m b er o f M ed i anDya ds type propo r t ion in terac t ions P propo r t ion
1987-1988
N u m b e r o fin terac t ions
Siblings
Peers
N o n -p ee r s
Strong 0.25 160 0.21M ild 0.72 435 0.72Reciprocal 0-04 36 0.06
<0.001Strong 0.18 87 0.29M ild 0.69 328 0.69Reciprocal 0.09 29 0-05
<0.001Stro ng 0-32 192 0-29M ild 0.61 405 0.66
Reciprocal 0.04 28 0.00< 0 '0 0 1
12136 6
38
11028 4
22
25 349 5
21
<0.001
<0.001
<0.001
Prob abi l i t ies represent the resul ts of ch i-squared tests , df= 2 in a ll cases.
Table I I I . Com par i son of p ropor t ions o f St rong and Reciprocal Aggress ion between dyads
1986-1987
T y p e o f D y ad s D i r ec t io n o faggression com pared P difference P
1987-1988
D i rec t io n o fdifference
Stron g Sibl ing versus peer NS NSSibl ing versus non -pe er NS 0-03Peer versus non-pe er 0 .03 Peer < non-pe er NS
Reciprocal Siblin g versus pee r NS NSSibl ing versus non -pee r NS 0"02Peer versus non-pe er NS 0 '05
Sib l ing < non-pe er
Sib l ing > non-pe erPeer > non-p eer
Probabi l i t ies are der ived f rom M an n-W hi tn ey U-tes ts .
h i g h e r r a te s o f a g g r e s s i o n t h a n l o w - r a n k i n g m a l e s
( m e d i a n t e s t: m e d i a n = 0 . 46 , N m a l e s a b o v e = 0 , N
m a l e s b e l o w = 5 , N f e m a l e s a b o v e = 6 , N f e m a l e s
bel ow --- 3, P < 0"03).
Com ponents of Aggression
T h e t o ta l n u m b e r s o f i n t e r a c ti o n s o f e a c h c o m -
p o n e n t o f a g g r e s s io n ( S t r o n g , M i l d , R e c i p r o c a l )
w e r e t e s t e d f o r e a c h c a t e g o r y o f d y a d s ( s i b l in g s ,
p e e r s, n o n - p e e r s ) a g a i n s t t h e n u l l h y p o t h e s is t h a t
t h er e w o u l d b e a n e q u a l a m o u n t o f e a ch o f t h e c o m -
p o n e n t s i n t h e m o n k e y s ' a g g r e s s i v e e n c o u n t e r s .M i l d A g g r e s s io n w a s t he m o s t f r e q u e n t c o m p o n e n t
w i th S t r o n g A g g r e s s io n b e i n g s e c o nd a n d R e c i p r o -
c a l A g g r e s s i o n t h e l e a s t f r e q u e n t ( T a b l e I I ) . T h e
p r o p o r t i o n s o f S t ro n g a n d R e c i p ro c a l A g g r e s s io n
w e r e t h e n c o m p a r e d b e t w e e n e ac h p a i r o f g r o u p s
( T a b l e I I I ) . W h e r e d i f f e re n c e s w e r e s i g n i f ic a n t , t h e r e
w a s m o r e S t r o n g A g g r e s s i o n a m o n g n o n - p e e r s
t h a n e i t h e r s i b l i n g s o r p e e r s , a n d l e ss R e c i p r o c a l
A g g r e s s io n a m o n g n o n - p e e r s t h a n e i th e r s i b li n gs
o r p e e r s .
Reciprocal a nd non-reciprocal partne rs
T o f i n d o u t w h e t h e r m o r e a f f i l i a t e d n o n - s i b l i n g
d y a d s a r e l e s s l i k e ly t o h a v e s e r i o u s c o n f l i c t s t h a n
o t h e rs , t h e p r o p o r t i o n s o f S t r o n g A g g r e s s i o n w e r ec o m p a r e d b e t w e e n r e c i p r o c a l a n d n o n - r e c i p r o c a l
p a r t n e r s ( F i g . 3 ). I n f a c t, a g g r e s s io n b e t w e e n n o n -
s i b l in g r e c i p r o c a l g r o o m i n g d y a d s w a s u s u a l l y
8/3/2019 Honess 2006
http://slidepdf.com/reader/full/honess-2006 7/14
Janus." Aggression in young rhesus monkeys 12 7
0 '5
0"4
0 "3
.~ 0 .2
~ 0 , 1
0o
(n N
0"5
o
0 .4-g
0" 3
( a )
Play
8 2 2
(b)
Grooming
9 21
Proximity
6 24
0 2 I t.1
Play
N 9 27
Grooming Proximity
7 29 5 31
Figure 3. Median proportions of Strong Aggression inconflicts of non-sibling reciprocal ([ ]) and non-reciproc al
([] ) play, groom ing and prox imity partners. Bars rep-resent interquartile intervals. (a) 1986-1987; (b) 198%1988.
c h a r a c t e r iz e d b y s l ig h t ly lo w e r p r o p o r t i o n s o f
S t r o n g A g g r e s s i o n ( s e e F i g . 3 ), b u t t h e s e d i f fe r e n c e s
d i d n o t r e a c h s t a t i s t i c a l s i g n if i ca n c e . I n t e r e s t i n g l y ,
h o w e v e r , t h e r e w a s a l s o , a n d m o r e c l e a r l y , l e ss
S t r o n g A g g r e s s i o n a n a o n g n o n - s i b l i n g r e c i p r o c a l
p l a y p a r t n e r s. I n g e n e r a l , a m o n g n o n - s i b li n g s ,
p a r t n e r s r e c i p r o c a l i n o n e o f th e t h r e e a f f i li a t iv e
b e h a v i o u r p a t t e r n s t e n d e d t o h a v e l e s s s e r i o u s
c o n f l ic t s t h a n t h e n o n - r e c i p r o c a l o n e s.
Individual compar&ons
I n t h e l i g h t o f t h e f a c t t h a t t h e r e w a s m o r e
a g g r e s s i o n a m o n g s i b l in g s , t e s t i n g p e r c e n t a g e s
r e v e a le d r e la t i v e c o n t r i b u t i o n s o f e a c h c o m p o n e n t
t o t h e t o t a l a m o u n t o f a g o n i s t i c i n t e r a c ti o n s . A s
w i t h t h e t o t a l a m o u n t o f a g g r e s s i o n (s e e a b o v e ) ,
o n l y i n d i v i d u a ls t h a t h a d b o t h a s i b l in g a n d a
n o n - s i b l in g w e re c o n s i d e r e d , a n d t h e p r o p o r t i o n so f e a c h t y p e o f a g g r e s s i o n d i r e c t e d t o a n d f r o m
s i b li n g s a n d n o n - s i b li n g s w e r e c o m p a r e d . M i l d
A g g r e s s i o n w a s t h e m o s t f r e q u e n t t y p e o f a g -
g r e s s i o n a m o n g i m m a t u r e i n d i v i d u a l s ( F i g . 4 ) ,
b o t h a m o n g s i b li n g s a n d n o n - s ib l in g s . N o n e o f t h e
d i f fe r e n c e s b e t w e e n t h e t w o g r o u p s w a s s i g n i f i c a n t
i n t h e f i rs t s e a s o n . I n t h e s e c o n d , h o w e v e r , t h e p e r -
c e n t a g e o f S t r o n g A g g r e s s i o n g i v e n w a s h i g h e r
a m o n g n o n - s i b l i n g s t h a n a m o n g s i b l in g s ( Z =
- 2 " 2 3 , N = 14 , P < 0 - 0 1 ) , b u t t h e p e r c e n t a g e o f
R e c i p r o c a l A g g r e s s i o n gi v e n w a s h i g h e r a m o n g s i b-
l i n g s t h a n a m o n g n o n - s i b l i n g s ( Z = - 1 .7 0, N = 1 4,
P < 0 . 0 5 ) .
C o n t e x t o f A g g r e ss io n
O u t o f 1 70 0 c o n f l ic t s b e t w e e n i m m a t u r e i n d i v i d -
u a l s i n t h e f i r s t s e a s o n , t h e c o n t e x t o f 8 13 ( 4 7 . 8 % )
w a s r e c o r d e d . O u t o f 1 7 10 c o n f l ic t s i n t h e s e c o n d
s e a s o n , t h e c o n t e x t w a s k n o w n i n 8 1 7 c a s e s
( 4 7 - 8 % ) .
T h e d i s t r i b u t i o n o f a g o n i s ti c in t e r a c t io n s a m o n g
c o n t e x t s i n e a c h s e a s o n a m o n g s i b l in g s a n d n o n -
s i b l in g s s e p a r a t e l y i s s h o w n i n T a b l e I V . I n n o n -
s i b l i n g d y a d s t h e o b s e r v e d f r e q u e n c i e s o f b o t h
s t r o n g l y a n d m i l d l y a g g r e s s i v e i n t e r a c t i o n s a r e s i g -
n i f i c a n t ly d i f f e re n t f r o m e x p e c t e d . O n e o f t h e c o n -
t e x t s m a i n l y r e s p o n s i b l e f o r t h is r e s u l t is p r o x i m i t y :
i n b o t h s e a s o n s t h e re w a s m o r e S t r o n g A g g r e s s i o n
i n t h is c o n t e x t t h a n e x p e c t e d , b u t l e s s M i l d
A g g r e s s i o n t h a n e x p e c t e d . A l s o i n b o t h s e a s o n s , i n
t h e p l a y c o n t e x t t h e r e w a s l es s S t ro n g A g g r e s s i o n
b u t m o r e M i l d t h a n e x p e c t e d . O t h e r d i f f e r e n c e s
w e r e n o t a s u n i f o r m . F o r e x a m p l e , i n t h e f i r s t
s e a s o n th e r e w a s m o r e S t r o n g a n d M i l d A g g r e s s i o n
t h a n e x p e c t e d i n t h e f o o d c o n t e x t , b u t i n t h e s e c o n d
s e a s o n t h e r e v e r s e w a s t r u e i n t h e s a m e c o n t e x t .
A m o n g t h e f o u r m o s t f r e q u e n t c o n t e x t s o f
a g g r e s s i o n ( p l a y , p r o x i m i t y / c o n t a c t , f o o d / w a t e r
a n d o b j e c t ) p r o x i m i t y w a s t h e m o s t f r e q u e n t , t h e n
p l a y , t h e n f o o d / w a t e r a n d l a s t l y o b j e c t ( T a b l e IV ) .
T h e o n l y r e v e r s a l f r o m t h i s p a t t e r n o c c u r r e d i nM i l d A g g r e s s i o n c o n te x t s w h e r e p l a y w a s u s u a l l y a
m o r e f r e q u e n t c o n te x t t h a n p r o x i m i t y / c o n t a c t .
I n a l l c a s e s w h e r e d i f f e r e n c e s b e t w e e n s i b l i n g s
a n d n o n - s i b l i n g s i n t h e n u m b e r o f c o n f li c t s i n a p a r -
t i c u l a r c o n t e x t w e r e s i g n i f i c a n t ( M a n n - W h i t n e y ,
P < 0" 05 , T a b l e V ) , t h e r e w e r e m o r e o f t h e s e c o n -
f li c ts a m o n g s i b l in g s t h a n n o n - s i b l i n g s . T h e m o s t
c o n s i s t e n t w a s t h e c a s e o f p r o x i m i t y / c o n t a c t ,
w h e r e i n b o t h s e a s o n s s ib l in g s h a d m o r e M i l d a n d
R e c i p r o c a l A g g r e s s i o n c o n fl i c ts t h a n n o n - s i b l i n g s .
I t m u s t b e n o t e d , h o w e v e r , t h a t o n l y f o u r o f a l lt h e s e r e s u l t s ( u n d e r l i n e d i n T a b l e V ) w e r e u p h e l d
a f t e r t e s t i n g t h e d i f f e r e n c es in r e l a t i v e p r o p o r t i o n s
o f c o n f l i c ts i n p a r t i c u l a r c o n t e x t s .
8/3/2019 Honess 2006
http://slidepdf.com/reader/full/honess-2006 8/14
IO C
7 5
5 0
2 5
7 5
a )
. > " o $o~ 0 e #g"~ g
< I 0 0
b )
5 0
2 5
Sibl ing N0n-sibl ing
~5
0 __J
12 8 Animal Behaviour, 41, l
o~
,0
iSibling Non-sibl ing
Figure 4. The com ponents of aggression among siblings and no n-siblings: Strong A ggression (U]), M ild Aggression (~ )and Reciprocal Aggression ( 1) . The values represent percentages o f the total number of agonistic episodes ofindividuals that included both a sibling an d a non-sibling. (a) 1986 1987,N= 17; (b) 1987-1988, N = 14.
D I S C U S S I O N
T h e a g o n i s t ic i n t e ra c t i o n s o f i m m a t u r e r h e su s
m o n k e y s a s s h o w n i n t h i s p a p e r w e r e m o r e f r e q u e n t
a m o n g s i bl in g s a n d p e e r s t h a n a m o n g n o n - p e e r s .
H o w e v e r , t h e r e w a s l e ss S t r o n g A g g r e s s i o n a m o n g
s i b l in g s a n d p e e r s t h a n a m o n g n o n - p e e r s , a n d a l s oa m o n g n o n - s i b l in g r e c i p r o c al s o c i al p a r t n e r s t h a n
a m o n g n o n - r e c i p r o c a l p a r t n e r s. T h u s a l t h o u g h
h i g h l e v e l s o f a f f i l i a ti o n d o n o t p r e c l u d e h i g h l e v e l s
o f a g g r e s s i o n , t h e y d o m i t i g a t e i t s f o rc e .
I n a s t u d y o f t h e f u n c ti o n o f a g g re s s iv e b e h a v i o u r
i n r h e s u s m o n k e y s , B e r n s t e i n & E h a r d t ( 1 9 8 6 )
a r g u e d t h a t a g g r e s s i o n c o u l d h a v e a p o s i t i v e fu n c -
t i o n i n t h e s o c i a l i z a t i o n p r o c e s s . I n t h e i r v i ew , m o s t
a g g r e s s i o n a m o n g k i n , e s p e c i a l ly t h a t d i r e c t e d f r o m
o l d e r t o y o u n g e r a n i m a l s , s e r v e s a s a p u n i s h m e n t
f o r u n a c c e p t a b l e b e h a v i o u r . N e g a y a m a ' s ( 1 9 8 1 )f i nd i n g t h a t J a p a n e s e m o n k e y m o t h e r s b e h a v e
a g g r e s s i v e l y t o w a r d s t h e i r i n f a n t s a s a r e a c t i o n t o
t h e i n f a n t s ' b e h a v i o u r , a n d B e r n s t e i n & E h a r d t ' s
o w n r e s ul ts s h o w i n g t h a t r h es u s m o t h e r s a n d o l d e r
s i b l i n g s d i r e c t m o r e a g g r e s s i o n t o w a r d s y o u n g
m o n k e y s t h a n o t h e r g r o u p s m e m b e r s , s u p p o r t t h e ir
h y p o t h e s i s . H i g h e r l e v e l s o f a g g r e s s i o n a m o n g
i m m a t u r e s i b li n g s t h a n n o n - s i b li n g s i n m y s t u d y
s e e m t o a g r e e w i t h B e r n s t e i n & E h a r d t ' s ( 1 9 8 6 )
h y p o t h e s i s a s w e l l . T h e l o w e r a g g r e s s i o n a m o n gn o n - s i b l i n g s m i g h t h a v e b e e n d u e t o a f e a r o f r e t a l i -
a t i o n b y a m o t h e r . H o w e v e r , a m o n g i m m a t u r e
i n d i v i d u a l s in m y s t u d y , s a m e - a g e n o n - s i b l i n g s ,
i . e . p ee r s , h a d l ev e l s o f ag g r e ss io n a s h ig h a s s ib -
l i n gs , a n d h i g h e r t h a n n o n - p e e r s . T h i s c a n n o t b e
a c c o u n t e d f o r b y B e r n st e in & E h a r d t ' s h y p o t h e s i s ,
a s th e t h e o r y o f ' p u n i s h m e n t ' d o e s n o t w o r k w i t h
m o n k e y s o f t h e s a m e a g e . N e i t h e r c o u l d i t b e
e x p l a i n ed e n t i re l y b y t h e f e a r o f r e t a l i a ti o n h y p o t h -
e s is , b e c a u s e t h e n a g g r e s s i o n b e t w e e n p e e r s w o u l d
h a v e t o b e l e ss f r e q u e n t t h a n a m o n g s i b l in g s , w h i c hw a s n o t t h e c a se . I n a d d i t i o n , m o t h e r s i n t e r f e r e d in
m o r e s i b l i n g ( 7 % ) t h a n n o n - s i b l i n g c o n fl i c ts ( 5 % ,
Jan u s 1 9 8 9 b ) .
8/3/2019 Honess 2006
http://slidepdf.com/reader/full/honess-2006 9/14
Q
. f i
8
.9
8
0
v
i
6
0
8
.9
00
Janus. 9Aggression in young rhesus monkey s
9 . . ~ . o I I 7
9 . ~ . = . . 9 , , ~ , . - . . =
~ ~ . ~ ~ - - ~ ~o - ~ ~ ~ - . ~ ~, ~ -
1 2 9
o 9
I:::I
. 9 ~ . =
0 o~
9 ~ , ~ . ~ ~
~ .'~
~ , ~ ~ o
~ .~ . ~
~o~
8/3/2019 Honess 2006
http://slidepdf.com/reader/full/honess-2006 10/14
1 3 0 An imal Behaviour, 41 , 1
0
jm
o
0
0p
A ~ ~
z v
z ~
Z ~. ~ z , ~ Z ~ ~
o
o
" ~ o
8
r~
o-s--,
e. ,
9.
6II
a . ,
0
8
013
t~
r ,
8/3/2019 Honess 2006
http://slidepdf.com/reader/full/honess-2006 11/14
Janus: Aggression in youn g rhesus m onk eys 131
W h a t t h e n c o u l d b e th e r e a s o n f o r su c h a m a r k e d
d i f fe r e n c e b e t w e e n a f f il i a te d a n d n o n - a f f i l i a t e d
p a r t n e r s ? O n e o f t h e p o s s i b i l i t ie s i s o p p o r t u n i t y : i f
t w o m o n k e y s s h o w a h i g h d e g r e e o f a f f i li a t io n , t h e y
s p e n d a l o t o f t i m e t o g e t h e r , p l a y i n g , g r o o m i n g o r
j u s t s i t t i n g c l o s e t o e a c h o t h e r a n d t h u s t h e y h a v e
f a r m o r e c h a n c e o f g e t t i n g i n v o l v e d in a c o n f l i c t
t h a n m o n k e y s w h o a r e n o t t o g e t h e r s o f re q u e n tl y .
I n d e e d , i n t h e s a m p l e a s a w h o l e ( t h a t i s , s i b l i n g s
a n d n o n - s i b l i n g s c o m b i n e d ) , t h e r e i s a s i g n i fi c a n t
c o r r e l a t i o n b e t w e e n t i m e s p e n t i n p r o x i m i t y a n d
a g g r e s s i o n r a t e s . T h i s , h o w e v e r , p r o b a b l y r e s u l t s
f r o m t h e f a c t t h a t s i b l in g s s p e n d m o r e t i m e t o g e t h e r
t h a n n o n - s i b l i n g s ( J a n u s 1 9 8 9a ) a n d a r e a l s o m o r e
a g g r e s s i v e t o e a c h o t h e r t h a n n o n - s i b l i n g s , a s th i s
c o r r e l a t i o n i s w e a k e r w h e n t h e y a r e c o n s i d e r e d
s e p a r a t el y . A s t h e m a i n d i ff e re n c e i n t h e n u m b e r
o f c o n f l i c t s b e t w e e n s i b l i n g s a n d n o n - s i b l i n g s o c -
c u r r e d i n t h e p r o x i m i t y / c o n t a c t c o n t e x t , i t se e m s
l ik e l y t h a t p r o x i m i t y t o a t h i r d p a r t y o r c o m i n g t o o
c l o s e w h e n a s i b l in g d o e s n o t w a n t s u c h p r o x i m i t y
a r e m o r e c o n f l i c t -p r o v o k i n g s it u a t io n s t h a n o t h e rs .
T w o s i b li n g s h a v e o n l y o n e m o t h e r t o b e i n c o n t a c t
w i t h d u r i n g r e s t i n g t i m e s ; tw o n o n - s i b l i n g s w o u l d
b e s e e k in g p r o x i m i t y o f t h e i r o w n m o t h e r s . E v e n i f
w e a s s u m e t h a t a l l o t h e r g r o u p m e m b e r s , e x c e p t
m o t h e r s , a r e e q u a l l y a t t ra c t i v e a s p r o x i m i t y p a r t -
n e r s f o r t w o y o u n g m o n k e y s , a n d t h u s e q u a l l y
l i k e l y t o b e c o n t e s t e d a s a r e s o u r c e , t h e t w o s i b l in g s
w o u l d h a v e t o c o m p e t e o v e r a c ce s s t o t h e m o t h e r ,
w h e r e a s n o n - s i b li n g s w o u l d n o t , w h i c h p r o b a b l y
m a k e s t h e d i ff e r e n c e i n t h i s c a s e . A d d i t i o n a l c o m -
p e t i t i o n m i g h t o c c u r o v e r a c c e ss to o l d e r / y o u n g e r
s i b l i n g s a n d m a t e r n a l r e l a t i v e s , w h i c h a r e d i f f e r e n t
f o r t w o n o n - s i b l i n g s , b u t t h e s a m e f o r s i b l in g s .
C o n f l ic t s o v e r p r o x i m i t y t o a t h i r d p a r t n e r a r e
m o r e f r e q u e n t a m o n g s t r o n g l y a ff il i at e d p a r t n e r s
t h a n a m o n g l e s s - a ff i li a t e d o n e s i n r h e s u s m a c a q u e s( C o l v i n 1 9 8 2 ) a n d h a m a d r y a s b a b o o n s , Papio
hamadryas ( K u m m e r e t a l . 1 97 8) .
A g e c l e a rl y i n fl u e nc e d t h e p r o p o r t i o n o f a g -
g r e s s i o n g i v e n b y a n d r e c e i v e d f r o m i m m a t u r e
m o n k e y s : I n f a n t s r e c e iv e d m o s t a g g r e s s i o n f r o m
o t h e r i m m a t u r e i n d i v id u a l s , a n d g a v e l e a st . T h e y
w e r e t h u s m o r e o f t e n t a r g e ts o f a g g r e s s i o n t h a n
a g g r e s s o r s , w h e r e a s O l d J u v e n i l e s w e r e m o r e o f t e n
a g g r e s s o r s t h a n t a r g e t s i n i m m a t u r e a g g r e s s i o n .
T h e a g e d i f f e re n c e s i n t h e i n v o l v e m e n t i n a g o n i s t i c
i n t e r a c t i o n s a r e w e l l d o c u m e n t e d ( D i t t u s 1 97 7;d e W a a l 1 97 7; B e r m a n 1 98 0; W a l t e r s 1 98 0; H a y a k i
1 9 8 3 ; B e r n s t e i n e t a l . 1 9 8 3 ; B e r n s t e i n & E h a r d t
1 98 5) a n d g e n e r a l l y a g r e e w i t h r e s u l t s f r o m m y
s t u d y w h i c h i n d i c a t e t h a t t h e r a t e o f a g g r e s s iv e
e n c o u n t e r s i n w h i c h a m o n k e y i s i n v o l v e d i n c r e a s e s
w i t h a g e . T h e m o s t l i k e l y e x p l a n a t i o n s o f t hi s
d e v e l o p m e n t a l c h a n g e a r e t w o f o ld . F i r s t , g r o w i n g
i n d i v i d u a ls b e c o m e m o r e s e r io u s c o m p e t i t o r s f o r
r e so u r ces , b e th ey f o o d so u r ces ( e .g. Pe r e i r a 1 9 88 b )
o r so c ia l p a r tn e r s ( e .g . C o lv in 1 9 85 ). I n f ema le -
b o n d e d p r i m a t e s p e c ie s ( c f. W r a n g h a m 1 98 0)
m o t h e r s o f f e m a l e i n f a n ts r e c ei v e m o r e a g g r e s si o n
t h a n m o t h e r s o f m a l e i n fa n t s ( rh e s u s: S i m p s o n
1 98 3) a n d y o u n g f e m a l e s r e ce i v e m o r e a g g r e s s i o n
t h a n y o u n g m a l e s ( r h e s u s : o f f s p r in g o f l o w - r a n k i n g
f e m a l e s , t h i s s t u d y ; b o n n e t , Macaca radiata: Si lk
e t a l . 1 98 1 ). Th e ab o v e f ac t s su p p o r t t h i s f i rs t p o ss i -
b i l i ty : f e m a l e s w i l l s t a y i n t h e i r n a t a l g r o u p a n d
c o m p e t e w i t h a d u l t f e m a l e s , w h i l e m a l e s w i l l
e m i g r a t e ; t h e r e f o r e t h e e s t a b l i s h m e n t o f a c l e a r
d o m i n a n c e r e l a t i o n s h i p w i th a y o u n g f e m a l e is
m o r e i m p o r t a n t t h a n w i t h a y o u n g m a l e . S e c o n d , a s
t h e y g r o w u p , y o u n g a n i m a l s b e c o m e m o r e s o c i a l ly
c o m p e t e n t a n d m o r e a c t iv e l y i n v o l v e d in t h e s o c i a l
d y n a m i c s i n t h e i r g r o u p ( W a l t e r s 1 98 7; K u e s t e r &
Pau l 1 9 8 8 ; Pe r e i r a 1 9 8 8 b ) , an d th e r e f o r e th ey a l so
p a r t i c i p a t e m o r e f u l l y i n a g o n i s t i c i n t e r a c t i o n s
(Cheney 1978; Colv in 1985; Pere i ra 1988a, 1989) .
T h e e f fe c t o f a g e o n t h e b a l a n c e o f a g g r e s s i o n g iv e n
a n d r e c e i v e d ( I n f a n t s r e c e i v e m o r e t h a n t h e y g i v e,
n o d i f fe r e n c e i n Y o u n g J u v e n i l e s , O l d J u v e n i l e s g iv e
m o r e a g g r e s s i o n t h a n t h e y r e c e i v e ) r e f l e c t s t h i s
d e v e l o p m e n t a l i n c r e a s e .
T h e r e a r e r e p o r t s o f b o t h p o s s i b l e se x in f l ue n c e s
o n a g g r e s s i o n : t h a t m a l e s a r e m o r e a g g r e s s i v e
t h a n f e m a l e s (e . g. t o q u e m a c a q u e s , M aeaea s in ica:
D i t t u s 1 97 7; i n f a n t b a b o o n s , Papio s p . : Y o u n g e t a l.
1 98 2), o r t h a t f e m a l e s a r e m o r e a g g r e s s i v e t h a n
ma les ( e .g . r h esu s : Lo y e t a l . 19 8 4) . Of t en , t h o u g h ,
t h e d i r e c t i o n o f re s u l t s d e p e n d s o n t h e m e a s u r e u s e d .
B e r n s t e i n ( 19 7 2 ) f o u n d t h a t a l l a g o n i s t i c i n t e r a c -t i o n s w e r e m o r e f r e q u e n t a m o n g f e m a l e t h a n m a l e
p i g t a i l m a c a q u e s , Ma eaea nemestr ina , b u t d a m a g -
i n g a g g r e s s i o n w a s m o r e f r e q u e n t a m o n g m a l e s .
A m o n g s t u m p t a i l m a c a q u e s , Maeaea aretoides,
f e m a le s t h r e a t e n e d a n d b i t m o r e o f t e n t h a n m a l e s,
b u t t h e r e w a s n o d i f fe r e n c e i n o t h e r t y p e s o f a g -
g r e ss io n ( B er n s t e in 1 9 80 ). S imi l a r ly , t h e r e wer e
m o r e a p p r o a c h - a v o i d i n t e r a c t i o n s a m o n g a d u l t
f e m a le b a b o o n s , Papio eynoeephalus ursinus, t h a n
a m o n g a d u l t m a l e s, b u t o t h e r a g g r e s s iv e i n t e r-
a c t i o n s w e r e m o r e f r e q u en t a m o n g m a l e s ( S e y f a r th1 9 7 6 ) . C a p t i v e f e m a l e J a p a n e s e m a c a q u e s w e r e
l e ss a g g re s s i v e t h a n m a l e s , w h e n m e a n f r e q u e n c i e s
p e r h o u r w e r e c o n s id e r e d , b u t t h e y d i r e c t e d m o r e
8/3/2019 Honess 2006
http://slidepdf.com/reader/full/honess-2006 12/14
132 A nim al B e hav iour , 41 , 1
a g g r e s s i o n t o w a r d s a d u l t g r o u p m e m b e r s t h a n
m a l e s ( E a t o n e t a l . 1 98 1). F r e e - r a n g i n g r h e s u s
m a c a q u e f e m a l e s i n i t i a t e d m o r e a g g r e s s iv e i n c i-
d e n t s t h a n m a l e s , b u t t h e m e a n r a t e s o f a g g r e ss i o n
p e r m o n k e y w e r e h i g h er a m o n g m a l e s (T e a s e t al .
1982).
B e r n s t e i n & E h a r d t ( 1 9 8 5 ) r e p o r t e d t h a t i n f a n t
m a l e r h e s u s m a c a q u e s w e r e m o r e a g g re s s iv e t h a n
i n f a n t f e m a l e s b u t t h i s s ex d i f fe r e n c e r e v e r s e d w h e n
t h e y b e c a m e j u v e n i l e s . I t is a v e r y g o o d i l l u s t r a t i o n
o f t h e p o i n t t h a t a n y s e x d i f fe r e n c e s a r e n o t i n h e r e n t
p r o p e r t i e s o f a p a r t i c u l a r g e n d e r b u t r a t h e r a j o i n t
e f fe c t o f t h i s a n d m a n y o t h e r a d d i t i o n a l v a r i a b le s
( s e e D a t t a 1 98 3c ). R e c e n t l y , d e W a a l s u g g e s t e d t h a t
t h e s e x d i f f e re n c e s i n t h e e x p r e s s i o n o f a g g r e s s i o n
m a y b e m o r e q u a l i t a t iv e t h a n q u a n t i t a t i v e ( 19 8 9a ,
b ) , a s r e f l ec t ed in se l ec t iv i ty n r eco n c i l i a t io n e f f o r t s .
T h u s f e m a l es a p p e a r t o r e c o n c il e r e a d i ly w i t h a
l i m i t e d s et o f p a r t n e r s , u s u a l l y t h o s e w i t h w h o m
t h e y h a v e s t r o n g a f f il i a ti v e b o n d s ( e .g . c l o s e r e la -
t i v es , c l o s e f e m a l e a s s o c i a t e s) , b u t b e a r p e r s i s t e n t
' g r u d g e s ' t o o t h e r g r o u p m e m b e r s , w h i l e a m o n g
m a l e s t h e s e p a t t e r n s a r e m u c h l e ss e v i d e n t . E x c e p t
f o r t h e f a c t t h a t i n f a n t f e m a l e s a r e m o r e f r e q u e n t
t a r g e ts o f a g g re s s i o n b y o t h e r i m m a t u r e i n d i v i d u a ls
t h a n i n f a n t m a l e s , n o s e x d i ff e r e n ce s i n a n y a s p e c t
o f a g g r e s s i o n e m e r g e d i n m y s t u d y s a m p l e . T h i s
c o u l d r e f le c t t h e f a c t t h a t s e x u a l d i m o r p h i s m i n
s iz e a m o n g i m m a t u r e r h e s u s m o n k e y s i s o n l y sl ig h t .
I n m y s t u d y g r o u p , a n d p e r h a p s i n g e n e r a l , i t i s
p o s s i b l e t h a t t h e c o m b i n a t i o n o f f a c to r s l e a d i n g to
s e x d i ff e r e n ce s in a g g r e s s i v en e s s d o e s n o t o c c u r
u n t i l y o u n g m o n k e y s r e a c h p u b e r t y .
F o o d w a s t h e c o n t e x t o f t h e m o s t f r e q u e nt c o n -
f li ct s a m o n g u n r e l a t e d j u v e n il e v e r v e t m o n k e y s
( L e e 1 9 8 7 ) a n d s a v a n n a b a b o o n s ( P ap io c . c y no-
cephalus , Per e i r a 1 9 88 a) . Ju v en i l e v e r v e t s ib l in g s
a l s o h a d m o r e c o n fl ic t s i n a g r o o m i n g c o n t e x t t h a nu n r e l a t e d m o n k e y s ( L e e 1 98 7) . T h e s e f i n d i n g s h a v e
b e e n o n l y p a r t i a l l y c o n f i r m e d i n t h e p r e s e n t s t u d y .
C o n f li c ts d u r n g g r o o m i n g o c c u r r e d m o r e o f t e n
a m o n g s i b l in g s t h a n n o n - s i b l i n g s , a n d c o n f l ic t s
o v e r f o o d d i d c o n s t i t u t e s l i g ht l y l o w e r p r o p o r t i o n s
o f a ll c o n te x t s a m o n g s i b li n g s t h a n a m o n g n o n -
s ib l in g s . On ly th e f i r s t d i f f e r en ce , h o wev er , was
s i g n i f i c a n t . B o t h p o p u l a t i o n s o f v e r v e t s a n d o f
s a v a n n a b a b o o n s m e n t i o n e d a b o v e , ho w e v e r , w e r e
f r e e -l i v in g , w h e r e a s m y s u b j e c t s w e r e i n c a p t i v i t y
w h i c h m e a n t t h a t t h e y h a d f o o d a n d w a t e r a dl i b i t u m . F o r t h a t r e a s o n , i t is l i k e l y t h a t f o o d w a s
n o t a s i m p o r t a n t a r e s o u r c e a s i n n o n - c a p t i v e c o n -
d i t i o n s . C o n f l i c ts in a p r o x i m i t y c o n t e x t w e r e t h e
m o s t f r e q u e n t o f a l t c o n t e x ts , s u g g e s ti n g th a t p r o x -
i m i ty to a n o t h e r m o n k e y m a y b e a m o r e i m p o r t a n t
r e s o u rc e t h a n a n y o t h e r i n t h e p a r t i c u l a r c o n d i t io n s
i n o u r c o l o n y . T h e e v i d e n c e t h a t e s p e c i a l l y S t r o n g
A g g r e s s i o n o c cu r r e d b e t w e e n 32 a n d 4 2 % o f ti m e
i n t h i s c o n t e x t , s u p p o r t s t h e s e r i o u s n e s s o f t h i s
c o m p e t i t i o n . O n t h e o t h e r h a n d , p l a y w a s a l m o s t
u n i f o r m l y t h e m o s t f r e q u e n t c o n t e x t o f M i l d
A g g r e s s i o n , s u g ge s t in g t h a t p l a y i n g p r o v i d e s o p -
p o r t u n i t y f o r c o n fl i c t, b u t t h a t t h e s e c o n fl i c t s d o n o t
u s u a l l y c a r r y s o m u c h w e i g h t a s t h o s e i n v o l v i n g
p r o x i m i t y . I n t h e l i g h t o f t h e f a c t t h a t s i b l in g s
g r o o m e a c h o t h e r m u c h m o r e f r e q u e n t ly t h a n n o n -
s ib l in g s ( see Jan u s 1 9 89 a) , t h e tw ice o r m o r e f r e -
q u e n t c o n f l ic t s o c c u r r i n g i n t h e g r o o m i n g c o n t e x t
a m o n g s i b li n g s t h a n n o n - s i b li n g s a r e p r o b a b l y a
r e s u lt o f m o r e o p p o r t u n i t y .
t n c o n c l u s i o n , t h e d i f f e re n c e s i n t h e c h a r a c t e r o f
a g o n i s t i c i n t e r a c t i o n s b e t w e e n s i b l i n g s , p e e r s a n d
n o n - p e e r s w e r e n o t o n l y q u a n t i t a t i v e , b u t a l s o
q u a l i t a t i v e . T h e s e d i f f e r e n c e s , d e p e n d i n g o n t h e
s o c i a l r e l a t i o n s h i p b e t w e e n t w o p a r t n e r s , w e r e
m o r e e v i d e n t t h a n t h o s e d u e t o t h e i r i n h e r e n t i n d i -
v i d u a l c h a r a c t e r i s t i c s s u c h a s s e x o r a g e . T h i s s e r v e s
a s a n o t h e r i n d i c a t i o n t h a t b a s i c a l l y s o c i a l f a c t o r s
s u c h a s k i n s h i p o r a f f i l i a ti o n , w h i c h i n f l u e n c e t h e
l i v e s o f a d u l t p r i m a t e s s o s t r o n g l y , b e g i n t h e i r
in f lu en ce a t a v e r y ea r ly ag e .
A C K N O W L E D G M E N T S
I a m g r a t e f u l t o R o b e r t H i n d e a n d M i c h a e l
S i m p s o n f o r c r i ti c a l r e a d i n g o f t h e m a n u s c r i p t a n d
f o r t h e i r s u p p o r t a n d e n c o u r a g e m e n t w h i l e I w a s
c a r r y i n g o u t t h e r e s e a rc h . S a r o j D a t t a a n d S t e ve
H o l m a n p r o v i d e d h e lp f u l c o m m e n t s . I w a s s u p-
p o r t e d b y B e n e f a c t o r s ' R e s e a rc h S t u d e n t s h i p f r o m
t h e S t J o h n ' s C o l l e ge , C a m b r i d g e , U . K . T h e
m o n k e y c o l o n y w a s s u p p o r t e d b y t h e M e d i c a l
R e s e a r c h C o u n c i l , U . K .
R E F E R E N C E S
Altm ann, J. 1974. Observational study o f behaviour:sampling methods. Behaviour, 44, 227-267.
An derson, D. M . & Simpson, M. J. A . 1979. Breeding
performance of a cap tive colony of rhesus macaques(Macaca mulatta). Lab. Anim., 13, 275-281.
Berman, C . M. 1980. Ea rly agonistic experience and ra nkacquisition a mo ng free-ranging infant rhesus monkeys.Int. J. PrimatoL, 1, 153-170.
8/3/2019 Honess 2006
http://slidepdf.com/reader/full/honess-2006 13/14
J a nu s. " Ag g r e s s i o n i n y o u n g r h e s u s m o n k e y s 133
Berns t e in , I . S. 1972 . Da i ly ac t iv i t y cyc le s a nd we a the rin f luences on a p ig t a i l monkey g roup . Folia primatol.,18, 390-415.
Berns t e in , I. S . 1980 . Ac t iv i t y pa t t e rn s i n a s tum pta i l
m a c a q u e g r o u p (M aca ca arctoides). Folia primatol., 33 ,2 0 - 4 5 .
Bern ste in, I . S. & Eh ard t , C. L. 1985. Ag e sex di fferencesi n t h e e x p r e s s i o n o f a g o n i s t i c b e h a v i o u r i n r h e s u sm o n k e y (Macaca mulat ta) g r o u p s . J. comp. Psychol.,99, 115 132.
Berns t e in , I. S . & Eh a rd t , C . L . 1986 . Th e in f luence o fk i n s h i p a n d s o c i a li z a ti o n o n a g g r e ss i v e b e h a v i o u r i nr h e s u s m o n k e y s (M aca ca mulatta). Anita. Behav., 34,
739-747 .
Berns t e in , I . S . , Wi l l i ams , L . & Ramsay , M.1983 . The
e x p r e s s io n o f a g g r e s s i o n i n O l d W o r l d m o n k e y s . Int. J.Primatol., 4, 113-125.
C h e n e y , D . L . 1 9 7 8 . I n t e r a c t i o n s o f im m a t u r e m a l e a n d
f e m a l e b a b o o n s w i t h a d u l t f e m a le s . Anim. Behav. , 26 ,389-408 .
C h e n e y , D . L . & W r a n g h a m , R . W . 1 9 8 7 . P r e d a t i o n . I n :
Prim ate Societ ies (Ed . by B . B . Smut s , D. L . Cheney ,R . M . S e y f a r th , R . W . W r a n g h a m & T . T . S t r u h s a k e r ) ,p p . 2 2 7 5 3 9 . C h i c a g o : U n i v e r s i ty o f C h i c a g o P r e s s.
C o l v i n , J . D . 1 9 8 2 . S o c ia l i n t e g r a t i o n a n d e m i g r a t i o n
o f i m m a t u r e m a l e r h e s u s m a c a q u e s . P h . D . t h e si s ,C a m b r i d g e U n i v e r s i ty .
C o l v i n , J . D . 1 9 8 5 . B r e e d i n g - s e a s o n r e l a t io n s h i p s o fi m m a t u r e m a l e r h e s u s m o n k e y s w i t h f em a l e s: I . I n d i -v i d u a l d if f er e n ce s a n d c o n s t r a i n t s o n p a r t n e r c h o i c e .Int. J. P rimatol., 3, 261 287.
Colv in , J . & T i ss i e r , G.1985 . Af f i l i a t i on and rec ip roc i tyi n s i b l in g a n d p e e r r e l a t io n s h i p s a m o n g f r e e - ra n g i n gi m m a t u r e m a l e r h e s u s m o n k e y s . Anita. Behav., 33 ,
959-997 .
Croo k , J . H. 1970 . Soc i a l o rgan iza t ion and env i ro nm ent :a s p e c ts o f c o n t e m p o r a r y s o c ia l e t h o lo g y . Anim. Behav. ,18, 197-209.
Da t t a , S . B . 1983a . Re la t ive pow er and the acqu i s i t i on o frank . In : Primate Social Relat ionships . An Integrated
Approach (Ed . by R . A. Hinde ) , pp . 93 103 . Oxfo rd :Blackwell.
Da t t a , S . B . 1983b . Re la t i ve pow er and the ma in t e nan ceo f d o m i n a n c e . I n : Prim ate Social Relat ionships . An
IntegratedApproach (Ed . by R . A. H inde ) , pp . 103-112 .Oxford: Blackwel l .
Da t t a , S . B . 1983c . Pa t t e r ns o fa go n i s t i c i n t e rfe rence . In :Primate S ocia l Relationships. An Integrated A pproach
(Ed . by R . A . Hinde ) , pp . 289-297 . O xford : B lackwel l.
Di t t us , W. 1977 . The soc i a l r egu la t i on o f popu la t i ond e n s i t y a n d a g e - s e x d i s t r i b u t i o n in t h e t o q u e m o n k e y .Behaviour, 63 , 281-322 .
D i x s o n , A . F . 1 9 8 0 . A n d r o g e n s a n d a g g r e s s iv e b e h a v i o rin pr ima tes: a review. Aggress. Behav., 6 , 37-67 .
D r i c k a m e r , L . C . 1 9 7 4 . A t e n - y e a r s u m m a r y o f r e p r o -
d u c t i v e d a t a f o r f r e e - r a n g i n g M acaca mulat ta . Foliaprimatol., 21 , 61-80 .
D r i c k a m e r , L . C . 1 9 7 5 . Q u a n t i t a t i v e o b s e r v a t i o n o f b e -h a v i o u r i n f r e e - ra n g i n g Macaca mulat ta: m e t h o d o l o g ya n d a g g r e s si o n . Behaviour, 55 , 209-236 .
E a t o n , G . G . , M o d a h l , K . B . & J o h n s o n , D . F . 1 9 8 1 .A g g r e s s i v e b e h a v i o r i n a c o n f i n e d t r o o p o f J a p a n e s e
macaques : e f fec t s o f dens i ty , sea son and gende r .Aggress. Behav., 7, 145 164.
Eha rd t , C . L . & Be rns t e in , I. S . 19 87 . Pa t t e r ns o f af fi li -a t i o n a m o n g i m m a t u r e r h e s u s m o n k e y s (M a c a c amulatta). Am. J. Primatol., 13 , 255-269 .
G l i c k , B . B . , E a t o n , G . G . , J o h n s o n , D . F . & W o r l e i n ,J . M . 1 9 8 6 . D e v e l o p m e n t o f p a r t n e r p r e f e r en c e s in
J a p a n e s e m a c a q u e s (Macacafuscata): effects o f gend era n d k i n s h i p d u r i n g t h e s e c o n d y e a r o f l i f e . Int. J.
Primatol., 7 , 467-479 .
H a y a k i , H . 1 9 8 3 . T h e s o c ia l i n t e r a c ti o n s o f ju v e n i l e
J a p a n e s e m o n k e y s o n K o s h i m a i s l e t . Primates, 2 4 ,139-154.
Janus , M . 1989a . Rec ip roc i ty i n p lay , g room ing andp r o x i m i t y i n s i b li n g a n d n o n s i b l i n g y o u n g r h e s u sm o n k e y s . Int. J. Primatol., 10 , 243-261 .
J a n u s , M . C . 1 9 89 b . S o c ia l d e v e l o p m e n t a n d b e h a v i o u r a lr e c i p ro c i ty i n y o u n g r h e s u s m o n k e y s w i t h t h e i r s ib l in g s
a n d n o n - s i b li n g s . P h . D . t h es is , C a m b r i d g e U n i v e r s i ty .
Kues t e r , J . & Pau l , A. 1988. Ra nk re l a t i on s o f uven i l e and
s u b a d u l t n a t a l m a l e s o f B a r b a r y m a c a q u e s (M a c a c asylvanus) a t A f f e n b e r g S a le m . Foliaprimatol., 51 , 33-44 .
K u m m e r , H . , A b b e g l e n J . J ., B a c h m a n , C h . , F a l e t t , J . &S ig g, H . 1 9 7 8 . G r o o m i n g r e l a t i o n s h i p s a n d o b j e c tc o m p e t i t i o n a m o n g h a m a d r y a s b a b o o n s . I n : Recen t
Advances in Primatology. Vo l. L Behaviour (Ed . by D. J .C h i v e r s & J . H e r b e r t ), p p . 3 1 - 3 8 . L o n d o n : A c a d e m i cPress.
Lee, P . C . 1987 . S ibsh ips : coop e ra t ion a nd co mp e t i t i ona m o n g i m m a t u r e v e r v e t m o n k e y s . Primates, 28, 47 59.
Loy , J . 1971 . Es t rous behav iour o f f r ee - rang ing rhesus
m o n k e y s ( M . mulatta). Primates, 12, 1-31.Loy , J . , Loy , K. , Ke i fe r , G. & Conoway , C . 1984 . The
b e h a v i o r o f g o n a d e c t o m i z e d r h e s u s m o n k e y s . Contrib.Primatol., 20 .
M eln i ck , D. J . & Pea r l , M. C . 1987 . Ce rco p i thec ines inm u l t i m a l e g r o u p s : g e n e t i c d i v e r s i t y a n d p o p u l a t i o ns t ruc tu re . In : Primate Societ ies (Ed . by B . B . Smut s ,D . L . C h e n e y , R . M . S e y f a r th , R . W . W r a n g h a m &
T. T . S t ruhsake r ) , pp . 121-134 . C h icago : Unive rs i t y o fChicago Pre ss .
M i c h a e l , R . P . & Z u m p e , D . 1 9 7 0 . A g g r e s s i o n a n dg o n a d a l h o r m o n e s i n c ap t i v e r h e s u s m o n k e y s (M a c a c a
mulatta). Anita. Behav., 18, 1-10.
Neg ayam a , K . 1981 . M a te rn a l aggress ion to i ts o f f sp r ingi n J a p a n e s e m o n k e y s . J. Hum. Evol . , 10, 523-527.
Pe re i ra , M. E . 1988a . Agoni s t i c i n t e rac t ions o f j uven i l eb a b o o n s . I . F u n d a m e n t a l f e a t u r e s . Ethology, 79 , 195-217.
Pe re i ra , M. E . 1988b . E f fec ts o f age and sex on in t ra -g ro ups p a c in g b e h a v i o u r i n u v e n i le s a v a n n a h b a b o o n s , Papiocynocephalus cynocephalus. Anim. Behav., 36, 184-204.
Pe re i ra , M. E . 1989. Ag oni s t i c i n t e rac t ions o f j uven i l es a v a n n a b a b o o n s . I I . A g o n i s t ic s u p p o r t a n d r a n kacqu i s i t i on . Ethology, 80, 152-171.
S a u n d e r s , C . D . 1 98 7 . G r o o m i n g q u a l i ty i n r e l a ti o n t ot i ck dens i ty and rec ip roc i ty be tween pa r tne r s . A m . J .
Primatol., 12, 369.Seyfa r th , R . M. 1976. Soc i a l r e l a t i onsh ip s am ong ad u l tf e m a le b a b o o n s . Anita. Behav., 24 , 917-938 .
Siegel, S. 1956. Nonparam etric Statistics for the Behav-ioral Sciences. T o k y o : M c G r a w - H i l l K o g a k u s h a .
8/3/2019 Honess 2006
http://slidepdf.com/reader/full/honess-2006 14/14
1 3 4 A n i m a l B e h a v i ou r , 4 1 , 1
Si lk , J . B . , Samue l s , A. & Ro dm an , P . S . 1981 . Th ein f luence o f k insh ip , r ank and sex on a f f i l i a t i on anda g g r e s s i o n b e t w e e n a d u l t f e m a l e a n d i m m a t u r eb o n n e t m a c a q u e s (Macaca radiata). Behaviour , 78 ,
111-137 .Simps on , M . J . A. 1983 . E f fec t o f t he sex o f an i n fan t
o n t h e m o t h e r - i n f a n t r e l a t i o n s h i p a n d t h e m o t h e r ' s
s u b s e q u e n t r e p r o d u c t io n . I n : Prim ate Soc ial Relat ion-ships. An Integrated Approach ( E d . b y R . A . H i n d e ) ,pp. 53 57. Ox ford: Blackwell .
Smu t s , B . B . 1987 . Gen de r , agg ress ion , and in f luence . In :Prim ate Societ ies (Ed . by B . B . Smut s , D. L . Cheney ,R . M . S e y f a r th , R . W . W r a n g h a m & T . T . S t r u h s a k e r ),
pp . 400-412 . C h icago : Unive rs i t y o f Ch icago Pre ss .Soka l , R . & Rohl f , F . 1981 . Biometry. 2 n d e d n . S a n
F r a n c i s c o : W . H . F r e e m a n .
Teas , J . , Fe ldman , H. A. , R ich i e , T . L . , Tay lo r , H. G. &Southw ick , C . H. 1982 . Aggress ive behav io r i n t he f ree-
r a n g i n g rh e s u s m o n k e y s o f K a t m a n d u , N e p a l. Aggress.Behav., 8, 63 77.
d e W a a l , F . B . M . 1 9 7 7 . T h e o r g a n i s a t i o n o f a g o n i s ti c
r e l a ti o n s w i t h i n t w o c a p t i v e g r o u p s o f J a v a m o n k e y s(M aca ca fascicularis). Z. Tierpsychol., 44, 2 2 5 5 8 2 .
d e W a a l , F . B . M . 1 9 89 a. C o m m i t m e n t s a n d g r u d g e s .Politics Life Sci., 8, 27 30.
de Waa l , F . B . M. 1989b . Peacemaking among Primates.
C a m b r i d g e , M a s s a c h u s e t t s : H a r v a r d U n i v e r s i t y P r e ss .de Waa l , F . B . M. & Lut t re l l , L . M. 1985 . The fo rma l
h i e r a r c h y o f r h e s u s m a c a q u e s : a n i n v e s t i g a ti o n o f t h eba red - t ee th d isp l ay . Am . J. Primatol. , 9, 73 85.
W a i t e r s , J . 1 9 8 0 . I n t e r v e n t i o n s a n d t h e d e v e l o p m e n t o fd o m i n a n c e r e l a t i o n s h i p s i n f e m a l e b a b o o n s . Folia
primatol., 34 , 61-89 .W a i t e r s , J. R . 1 9 8 6 . K i n r e c o g n i t i o n in n o n h u m a n p r i -
ma te s . In : Kin Recognition in An im a& (Ed . by D. F .
F l e t c h e r & C . D . M i t c h en e r ) , p p . 3 5 9 - 3 9 4 . N e w Y o r k :J o h n W i l e y.
W al t e r s , J . R . 1987. T ran s i t i on to adu l tho od . In : PrimateSocieties (Ed . by B . B . Smut s , D. L . Cheney , R . M.S e y f a r th , R . W . W r a n g h a m & T . T . S t r u h s a k e r ) , pp .
358 369 . Ch icago : U nive rs i t y o f Ch icag o Pre ss .W i l son , A. P . & Boe lk ins , R . C . 1970 . Ev idence fo r
s e a s o n a l v a r i a t i o n i n a g g r es s iv e b e h a v i o u r i n M a c a c a
mulatta. Anim. Behav., 18 , 719-724 .W r a n g h a m , R . W . 1 9 8 0 . A n e c o lo g i ca l m o d e l o f fe m a l e -
b o n d e d p r i m a t e g ro u p s . Behaviour, 7 5 , 2 6 ~ 3 0 0 .Y o u n g , G . E . , C o e l h o , A . M . J r & B r a m b l e t t , C . A . 1 9 82 .
T h e d e v e l o p m e n t o f g r o o m i n g , s o c i o s e x u al b e h a v i o u r ,p l a y a n d a g g r e s s io n i n c a p t iv e b a b o o n s i n t h e i r f ir s t tw oyears. Primates, 23 , 511-519 .