A Comparative Note on Early Sibling Aggression in Two Related Species: The Iberian and the Eurasian Lynx.

Abstract

Early sibling fights in Eurasian and Iberian lynxes differ from other types of behavior
in a lack of ritualized elements (threats) and a high motivation level. In 2005 sudden
aggression, which ended up in siblicide, took place in the first Iberian lynx litter born
in captivity. Fights became a problem, turning into one of the highest risks of mortality
for captive born cubs. Fights started spontaneously, without any indication of previous
aggression, with a very sudden and fast attack of one of the cubs in the litter. This
aggression did not take place while the cubs were nursing or eating, and it did not
appear to be caused by any kind of competition. Fights were not the result of an
escalation of other social interactions, most times they occurred without any previous
interaction (e.g., while one of the cubs was sleeping or just sitting, looking away). Litter
size didn’t influence fight probability or cub mortality in any of the two species. Age at
which fights occurred varied from 36-64 day in Eurasian lynx litters. In naturally raised
Iberian lynxes, the appearance of sibling fights was observed during 36-63 days of
life. In general, fights occurred between the 6th and 8th the Eurasian cases (18/20),
but mostly during the seventh week. In Iberian lynx litters,
77% (10/13) of fights also occurred between the 6th frequent during the 6th
-8th week of the cub’s life in 90% ofpostnatal weeks, being more
week.Duration of after-fight aggression varied across Iberian
lynx litters (median=14; min=1; max=95 days). The aggressive period in Iberian lynx
lasted around 63 days (min=45; max=144). The number of attacks was higher in
Eurasian than in Iberian lynx fights, but the after-fight aggressive period in Eurasian
lynx was much shorter than in the Iberian lynx. Both differences could be caused by
either the after-fight husbandry procedures used in the endangered species or by
species-specific differences. Although fights occurred between cubs of the same and
different genders, body size made a difference. Female cubs were aggressors more
often than males in Eurasian lynx and the opposite was true for Iberian lynx litters.
Sex ratio of aggressors did not differ from overall sex ratio in lynx litters. In general,
the aggressor was larger than the attacked cub. Although several characteristics differ
between Eurasian and Iberian lynx fights, this phenomenon is similar in both species,
yet it differs from sibling aggression in other taxa.

Full text

Ib e r I a n l y n x
e x
s I t u
c o n s e r v a t I o n : a n In te r dI sc I pl I na ry a p p r o a c h
as t r I d va r g a s , ch r I s t I n e br e I t e n m o s e r & ur s br e I t e n m o s e r
Fu n d a c I ó n bI o d I v e r s I d a d / ca t sp e c I a l I s t gr o u p
Cats are intended to teach us that not everything in nature has
a function.
Joseph Wood Krutch
(1893-1970)

a c o m p a r a t I v e n o t e o n e a r l y s I b l I n g a g g r e s s I o n I n t w o r e l a t e d s p e c I e s : t h e Ib e r I a n a n d t h e eu r a s I a n l y n x
no t a c o m p a r a t I v a s o b r e l a a g r e s I ó n p r e c o z e n t r e h e r m a n o s d e c a m a d a e n d o s e s p e c I e s a F I n e s : e l l I n c e I b é r I c o y e l l I n c e e u r o a sIá t I co
an a s t a s Ia l. an t o n e v I c h , se r g e y na I d e n k o , Ju a n a be r g a r a , ev a v á z q u e z , an a st a s I o vá z q u e z ,
Ja v I e r ló p e z , an t o n I o pa r d o , an t o n I o rI v a s , Fe r n a n d o ma r t í n e z a n d as t r I d va r g a s

A comparative note on early
sibling aggression in two
related species: the Iberian and
the Eurasian lynx
Nota comparativa sobre la agresión
precoz entre hermanos de camada en dos
especies anes: el lince ibérico y el lince
euroasiático
an a s ta s I a l. an t o n e v I c h , se r g e y na I d e n k o , Ju a n a be r g a r a ,
ev a vá z q u e z , an a s t a s I o vá z q u e z , Ja v I e r ló p e z , an t o n I o pa r d o ,
an t o n I o rI v a s , Fe r n a n d o ma r t í n e z a n d as t r I d va r g a s
Re s u m e n
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Ib e r I a n l y n x
e x
s I t u
c o n s e r v a t I o n : a n In te r dI sc I pl I na ry a p p r o a c h
as t r I d va r g a s , ch r I s t I n e br e I t e n m o s e r & ur s br e I t e n m o s e r
Fu n d a c I ó n bI o d I v e r s I d a d / ca t sp e c I a l I s t gr o u p



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
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   
     

 


      
       
    
          


Pa l a b R a s c l a v e

ab s t R a c t
Early sibling ghts in Eurasian and Iberian lynxes differ from other types of behavior
in a lack of ritualized elements (threats) and a high motivation level. In 2005 sudden
aggression, which ended up in siblicide, took place in the rst Iberian lynx litter born
in captivity. Fights became a problem, turning into one of the highest risks of mortality
for captive born cubs. Fights started spontaneously, without any indication of previous
aggression, with a very sudden and fast attack of one of the cubs in the litter. This
aggression did not take place while the cubs were nursing or eating, and it did not
appear to be caused by any kind of competition. Fights were not the result of an
escalation of other social interactions, most times they occurred without any previous
interaction (e.g., while one of the cubs was sleeping or just sitting, looking away). Litter
size didn’t inuence ght probability or cub mortality in any of the two species. Age at
which ghts occurred varied from 36-64 day in Eurasian lynx litters. In naturally raised
Iberian lynxes, the appearance of sibling ghts was observed during 36-63 days of
life. In general, ghts occurred between the 6th and 8th week of the cub’s life in 90% of
the Eurasian cases (18/20), but mostly during the seventh week. In Iberian lynx litters,
77% (10/13) of ghts also occurred between the 6th-8th postnatal weeks, being more
frequent during the 6th week.Duration of after-ght aggression varied across Iberian
lynx litters (median=14; min=1; max=95 days). The aggressive period in Iberian lynx
lasted around 63 days (min=45; max=144). The number of attacks was higher in
Eurasian than in Iberian lynx ghts, but the after-ght aggressive period in Eurasian
lynx was much shorter than in the Iberian lynx. Both differences could be caused by
either the after-ght husbandry procedures used in the endangered species or by
species-specic differences. Although ghts occurred between cubs of the same and
different genders, body size made a difference. Female cubs were aggressors more
often than males in Eurasian lynx and the opposite was true for Iberian lynx litters.
Sex ratio of aggressors did not differ from overall sex ratio in lynx litters. In general,
the aggressor was larger than the attacked cub. Although several characteristics differ
between Eurasian and Iberian lynx ghts, this phenomenon is similar in both species,
yet it differs from sibling aggression in other taxa.
Ke y w o R d s
Iberian lynx, Eurasian lynx, siblicide, aggressive behavior

a c o m p a r a t I v e n o t e o n e a r l y s I b l I n g a g g r e s s I o n I n t w o r e l a t e d s p e c I e s : t h e Ib e r I a n a n d t h e eu r a s I a n l y n x
no t a c o m p a r a t I v a s o b r e l a a g r e s I ó n p r e c o z e n t r e h e r m a n o s d e c a m a d a e n d o s e s p e c I e s a F I n e s : e l l I n c e I b é r I c o y e l l I n c e e u r o a sIá t I co
an a s t a s Ia l. an t o n e v I c h , se r g e y na I d e n k o , Ju a n a be r g a r a , ev a v á z q u e z , an a st a s I o vá z q u e z ,
Ja v I e r ló p e z , an t o n I o pa r d o , an t o n I o rI v a s , Fe r n a n d o ma r t í n e z a n d as t r I d va r g a s

A comparative note on early sibling
aggression in two related species:
the Iberian and the Eurasian lynx
an a s ta s I a l. an t o n e v I c h , se r g e y na I d e n k o , Ju a n a be r g a r a , ev a vá z q u e z , an a s t a s I o vá z q u e z , Ja v I e r ló p e z ,
an t o n I o pa r d o , an t o n I o rI v a s , Fe r n a n d o ma r t í n e z a n d as t r I d va r g a s
In t R o d u c t I o n
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
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            

           
 
           


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Re s u l t s a n d dI s c u s s I o n
co n t e x t
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                
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ag e o f f I g h t s
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fI g h t f e a t u R e s
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
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a c o m p a r a t I v e n o t e o n e a r l y s I b l I n g a g g r e s s I o n I n t w o r e l a t e d s p e c I e s : t h e Ib e r I a n a n d t h e eu r a s I a n l y n x
no t a c o m p a r a t I v a s o b r e l a a g r e s I ó n p r e c o z e n t r e h e r m a n o s d e c a m a d a e n d o s e s p e c I e s a F I n e s : e l l I n c e I b é r I c o y e l l I n c e e u r o a sIá t I co
an a s t a s Ia l. an t o n e v I c h , se r g e y na I d e n k o , Ju a n a be r g a r a , ev a v á z q u e z , an a st a s I o vá z q u e z ,
Ja v I e r ló p e z , an t o n I o pa r d o , an t o n I o rI v a s , Fe r n a n d o ma r t í n e z a n d as t r I d va r g a s
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we e K s o f l I f e
n o f c u b s w h I c h f o u g h t In t h I s w e e K
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Fi g u r e 1.
Ag e o F A g g r e s s o r i n ib e r i A n
l y n x F i g h t (m o t h e r -r A i s e d A n d
h A n d -r A i s e d l i t t e r s ). in 2009,
A t t h e t i m e o F u p d A t i n g t h i s
d A t A , s e v e n n e w F i g h t s h A d t A k e n
p l A c e : t h r e e o F t h e m d u r i n g
t h e 6t h w e e k o F l i F e , o n e F i g h t
d u r i n g t h e 7t h w e e k , t w o m o r e
d u r i n g t h e 8t h p o s t n A t A l we e k ,
A n d o n e i n t h e 9t h w e e k .
Fi g u r A 1.
ed A d d e l c A c h o r r o A g r e s o r
e n c A m A d A s d e l i n c e ib é r i c o .
(cr i A d o s p o r s u s m A d r e s y
c r i A d o s A l b i b e r ó n ).
en 2009, d u r A n t e l A r e v i s i ó n
d e e s t e c A p í t u l o , h A n t e n i d o
l u g A r s i e t e p e l e A s n u e v A s :
t r e s d e e l l A s d u r A n t e l A s e x t A
s e m A n A d e v i d A , u n A d u r A n t e l A
s é p t i m A s e m A n A , d o s d u r A n t e l A
o c t A v A s e m A n A p o s t n A t A l y u n A
m á s d u r A n t e l A n o v e n A .
Fi g u r e 2.
Ag e o F F i g h t A n d d u r A t i o n o F
A g g r e s s i v e p e r i o d i n ib e r i A n
l y n x l i t t e r s , n A t u r A l A n d h A n d -
r A i s e d .
th e e n d o F t h e A g g r e s s i v e
p e r i o d h A s b e e n c A l c u l A t e d F r o m
t h e F i r s t p e A c e F u l r e u n i o n .
(or A n g e : A g g r e s s i v e p e r i o d ;
g r e e n : p e A c e F u l p e r i o d ).
Fi g u r A 2.
ed A d e n l A q u e l A p e l e A t u v o
l u g A r y d u r A c i ó n d e l p e r i o d o
A g r e s i v o e n c A m A d A s d e l i n c e
i b é r i c o , t A n t o d e c r i A n z A
n A t u r A l c o m o A r t i F i c i A l . el F i n A l
d e l p e r i o d o A g r e s i v o h A s i d o
c A l c u l A d o A p A r t i r d e l A p r i m e r A
r e u n i ó n pA c í F i c A . (nA r A n j A :
p e r i o d o A g r e s i v o ; v e r d e :
p e r i o d o p A c í F i c o ).
bR I s a y bR e z o
cy n a R a y ca t a l P a
ca s t a ñ u e l a y ca m a R I n a
da l a I y da m a
es P l I e g o y Éb a n o
en d R I n o y eo n
eu c a l I P t o y eR I z o
en e b R o y en e a
eR o s y ÉR I c a
30 50 70 90 110 130 150
da y s o f l I f e
24
21
9
7
24
14
95
1
4

Ib e r I a n l y n x
e x
s I t u
c o n s e r v a t I o n : a n In te r dI sc I pl I na ry a p p r o a c h
as t r I d va r g a s , ch r I s t I n e br e I t e n m o s e r & ur s br e I t e n m o s e r
Fu n d a c I ó n bI o d I v e r s I d a d / ca t sp e c I a l I s t gr o u p
wh o a R e t h e a g g R e s s o R s
a n d t h e v I c t I m s?

   
     
        
        
      
    

  
 


      
        
        
      
       
    
      




Re s P o n s e o f m o t h e R s t o f I g h t I n g o f f s P R I n g







co n c l u s s I o n s
    

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a c o m p a r a t I v e n o t e o n e a r l y s I b l I n g a g g r e s s I o n I n t w o r e l a t e d s p e c I e s : t h e Ib e r I a n a n d t h e eu r a s I a n l y n x
no t a c o m p a r a t I v a s o b r e l a a g r e s I ó n p r e c o z e n t r e h e r m a n o s d e c a m a d a e n d o s e s p e c I e s a F I n e s : e l l I n c e I b é r I c o y e l l I n c e e u r o a sIá t I co
an a s t a s Ia l. an t o n e v I c h , se r g e y na I d e n k o , Ju a n a be r g a r a , ev a v á z q u e z , an a st a s I o vá z q u e z ,
Ja v I e r ló p e z , an t o n I o pa r d o , an t o n I o rI v a s , Fe r n a n d o ma r t í n e z a n d as t r I d va r g a s
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Re f e R e n c e s
Antonevich, A.L., Naidenko, S.V., 
      

 

Drummond, H.,  

Fraser, D., Thompson, B.K., 

Hofer, H., East, M.L.,  


Naidenko, S.V., Antonevich, A.L., 







Sokolov, V.E., Naidenko, S.V., Serbenyuk, M.A., 






Vargas, A., Martínez, F., Bergara, J., Klink, L.E., Rodríguez, J.,
Rodríguez, D., 



Vargas, A., Sánchez, I., Martínez, F., Rivas, A., Godoy, J.A.,
Roldan, E., Simón, M.A., Serra, R., Pérez, M.J., Sliwa, A.,
Delibes, M., Aymerich, M., Breitenmoser, U.,  

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