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A third species of lynx, the bobcat, found to experience early sibling aggression

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Early spontaneous sibling aggression is known in Eurasian lynx and Iberian lynx. It differs from other types of aggression in lynx and other animals. In 2010 similar sibling fights in a bobcat Lynx rufus litter were recorded at the Tchernogolovka Research Centre in Russia. http://www.catsg.org/catnews/20_cat-news-website/home/index_en.htm
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ISSN 1027-2992
CAT
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N° 59 | AUTUMN 2013
CATnews 59 Autumn 2013
02
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CATnews 59 Autumn 2013
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short communication
ANASTASIA ANTONEVICH1* AND SERGEY NAIDENKO1
A third species of lynx, the
bobcat, found to experience
early sibling aggression
Early spontaneous sibling aggression is known in Eurasian lynx and Iberian lynx.
It differs from other types of aggression in lynx and other animals. In 2010 similar
sibling fights in a bobcat Lynx rufus litter were recorded at the Tchernogolovka
Research Centre in Russia.
In most species of mammals sibling aggres-
sion is shown to be the direct result of es-
calated competition (Drummond 2006, Hofer
& East 2008). Early and spontaneous sibling
aggression occurs both in Eurasian Lynx lynx
(Sokolov et al. 1994) and Iberian L. pardinus
lynx litters (Vargas et al. 2005). These fights
differ from other types of aggression by ex-
hibiting high motivation levels, spontaneous
and apparently reasonless starts, and a lack
of ritualized threats. Without human interven-
tion they tend to occur only once in each litter,
but they can lead to serious wounds or even
death (Antonevich et al. 2009). Although Eu-
rasian lynx and Iberian lynx are known to be
the more closely related species in the genus
Lynx (Johnson et al. 2004), there are two more
species within the genus: the Canada lynx L.
canadensis and the bobcat. The only indirect
evidence that bobcats experienced this type
of aggression was known from the experience
at the Iberian lynx breeding program. Cynara,
an Iberian lynx cub and Catalpa, a 1-week
younger bobcat cub that acted as her ’surro-
gate sister’, were raised together to provide
the Iberian lynx cub with social experience.
They fought with each other at the ages of 74
and 68 days (Iberian Lynx Conservation Ex-situ
Bulletin ) 31, http://www.lynxexsitu.es/index.
php?accion=detalle_boletines&id=40#lince).
At that point there was no direct evidence of
bobcat cubs experiencing spontaneous sibling
aggression. The aim of our study was to find
out if bobcats also experience early sibling
fights.
Materials and methods
The study was conducted in Russia at the
Tchernogolovka Research Centre (A. N. Se-
vertsov Institute of Ecology and Evolution of
Russian Academy of Sciences), 60 km from
Moscow. Two litters of bobcats from the
same female were born in 2009 and 2010.
The cubs’ sex ratios were 0m:3f and 1m:2f.
The cubs were raised with their mother in a
74 m2 enclosure with a man-made wooden
den and natural tree trunks; they also had
access to an 8m2 cage. Dam and cubs were
fed daily with a diet of chicken with vitamin
additives. Water was provided ad libitum.
The cubs were marked with Nyanzol D fur
dye (Greenville Colorants, L.L.C. 20, Linden
Avenue East Jersey City, NJ 07305). During
the night, the enclosures were illuminated by
400W lamps that allowed for 24-hour video
recording using ILDVR 3000H4C PC DVR Card
and Hybrid DVR Server software.
Results
Indirect evidence
The Tchernogolovka Research Centre has
been breeding and studying Eurasian lynx for
more than 20 years, but the first bobcat litter
was born in 2009. In that first year no syste-
matic observations were conducted until the
cubs reached two months of age to ensure a
non-disturbance regime for the litter and their
nervous mother. Occasional observations and
handling did not reveal anything related to
potential fights. In 2010, during a regular
handling for weighing the cubs on day 62, we
observed a small hole under the cub’s fur but
we did not realize that it was due to a fight
until we watched the video.
Direct evidence
On 15 July 2010, at 01:00 h, when cubs were
61 days old, we recorded a fight in the se-
cond bobcat litter. The fight was started by
the male, the heaviest cub in the litter, and
it was directed towards one of the female
siblings. He attacked his sister 6 times. Ro-
les changed 50 minutes after the fight was
started. Afterwards, the previously neutral
female attacked the same victim in a similar
way as the first aggressor had. She attacked
her 7 times. In addition, at 03:33 h a three-
second fight occurred between the first set
of fighters. The whole event lasted 2 and a
half hours.
What did the fight look like?
The movements of spontaneous sibling
fights are very recognizable. One of the cubs
approaches another cautiously looking like
it is interested (ears up, neck tensed, head
slightly tilted forward) and sniffs the victim
slowly. It sniffs more and more strongly as
if it is trying to breathe in the victim, clo-
ser and closer, and suddenly makes a rapid
lunge and bites the victim on the nape.
The attacked cub rotates belly up, trying to
push the aggressor with its hind legs, and
to grasp the aggressor’s head with its front
legs. Further bites can be directed to the
neck or, in the case of successful defense,
to the legs. Cubs suffer injuries to the throat,
nape or legs afterwards.
The start
First, the male approached, pursued, sniffed
and attacked his sister while she was eating.
She left the food immediately, turned over
and rotated belly up to defend herself. The
cubs were locked together for a moment,
then separated and the female retreated.
One second later the same kind of attack took
place twice; the female managed to defend
herself, even though the male was attacking
her persistently. They moved around the en-
closure while still fighting. The fourth attack
was stronger, and the mother had to interve-
ne to try to separate her cubs, inserting her
head into the moving ball of clasped cubs.
It took her two minutes to separate them.
Eight minutes later the male was in pursuit
of his sister, trying to attack her again. The
victim prevented fights using a clear defen-
sive behaviour (moving aside, turning aside,
falling on the side with paws ready to fight,
preparing to cover the defenceless parts with
claws and teeth). These episodes of aggres-
sion were followed by breaks.
The change of the aggressor
During the first attacks the neutral cub snif-
fed the aggressor and kept herself away
from the fighters. Fifty minutes later, after
she sniffed and rubbed against her mother,
managing to get the dam to groom her, this
cub walked up to her sister (the victim).
This previously non-involved cub sat near
her sister for about a minute and then at-
tacked her with great strength. The mother
ran up to them and managed to separate
them with her head, sometimes pushing the
cubs to the ground with her forepaws. She
jumped around them, trying to bring herself
between them.
CATnews 59 Autumn 2013
32
early sibling aggression of the bobcat
Fig. 1. 30 days old bobcat cubs.
The end
The fight ended up slowly, with the victim de-
fending herself while the two aggressors en-
gaged in play wrestling and running-jumping
games with each other. At first, the victim
appeared scared, but soon after she joined
the siblings and the three of them began to
play together.
The mother’s role
The mother separated the cubs during some
of the fighting episodes, though in some
other cases the cubs managed to break free
from each other by themselves. The cubs
tried to suckle between the attacks, and they
even fell asleep by their mother through the
process. All the final attacks and reunions oc-
curred around the mother. In the last attack
the mother did not intervene during the fight
but sat between the cubs and tried to calm
them down by grooming them. After the fight
was over, the mother started to pace and the
cubs joined her one by one. They were follo-
wing the mother, playing with one another
with non-aggressive interaction.
Food and fighting
The litter was fed at midnight; the mother ate
and then offered food to the cubs. None of the
cubs was interested in eating. The mother ate
and then buried the remains of the meal. An
hour later two of the cubs woke up, sniffed
the chicken remains but were not interested
in eating. Both continued to move around the
enclosure. The third cub, a female, woke up
afterwards and started to eat. Two minutes
later the male tried to take her chicken away.
The female dragged the food around the en-
closure. The male followed his sister then she
stopped and continued eating. Suddenly the
male approached her and proceeded to at-
tack. The food was left aside until they took a
break from fighting. Then the aggressor went
back to his mother for nursing and the victim
went back to eating. No more attacks were
associated with feeding-time; no cub tried to
defend its food, even though the victim and
the second aggressor ate twice during the
fight. In general food was abandoned throug-
hout much of the aggressive episode.
Discussion
The age of the spontaneous sibling fights in
Eurasian and Iberian lynx ranges between
the 6th to 10th post-natal weeks (Antonevich
et al. 2009, Naidenko & Antonevich 2009).
The present fight took place during the 9th
post-natal week. As was the frequent case
in the other two lynx species, the heaviest
cub was the first aggressor. The fight started
during feeding, but it was clearly not caused
by any limited availability of food. Before the
fight none of the cubs ate although food was
given. After the fight the aggressor joined the
mother to be nursed while ignoring the chi-
cken. While fighting, the cubs did not pay any
attention to food, and during fight breaks the
victim went back to eating while the aggres-
sor showed no interest in food. It is possible to
suggest that eating here could be the displa-
cement behavior. From this single record we
cannot assert that fighting is totally unrelated
to food, as it is the case for other lynx spe-
cies, but we can prove that sibling aggression
occurs in at least three of the four lynx spe-
cies. These fights occur in almost every litter
of Iberian lynx (Antonevich et al. 2009), and
in more than in 50% of Eurasian lynx litters
(Naidenko & Antonevich 2009). The observed
fight was very similar to those that we saw in
Eurasian and Iberian lynx litters. The attack
was sudden and occurred at a particular age.
Cubs move extremely fast, totally concentra-
ted on the process, while the mother separa-
tes them strongly and persistently. The whole
episode of aggression lasted several hours
and was followed by peaceful relations. The
fight in the bobcat litter fits the scenarios of
fighting by the other two species. What the
species-specific differences are and how fre-
quent these fights are in bobcat litters have
yet to be studied. We would appreciate any
further information regarding sibling fights
in any lynx species, but especially in bobcats
and Canada lynx.
Acknowledgements
We are very grateful to our colleagues, especially
Evgeny Ivanov for installation of the cameras. The
work was supported by grant RFBR 12-04-32028.
References
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spotted hyenas: a long-term study of maternal
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Sociobiology 62, 341-451.
Naidenko S. V. & Antonevich A. L. 2009. Sibling ag-
gression in Eurasian lynx (Lynx lynx). In Iberian
Lynx Ex situ Conservation: An Interdisciplinary
Approach. Vargas A., Breitenmoser C., Breiten-
moser U. (Eds.) Fundación Biodiversidad, Mad-
rid, Spain, pp. 146-155.
Sokolov V. E., Naidenko S. V. & Serbenyuk M. A.
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Carnivora, Felidae). Zoologicheskii Zhurnal 73,
132–138. [In Russian with English summary]
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riguez J. & Rodriguez D. 2005. Iberian lynx ex-
situ Conservation Program Update. Cat News
43, 21-22.
1 Institute of Ecology and Evolution RAS, 119071,
Leninsky pr., 33, Moscow, Russia
*<anastasia-antonevich@yandex.ru>
... Sibling aggression occurs in half of the litters in Eurasian lynx (Sokolov et al., 1994) and almost all the Iberian lynx litters (Vargas et al., 2005;Antonevich et al., 2009), it leads to siblicide in some cases. Such aggression was found also in bobcats (Antonevich & Naidenko, 2013). Sibling aggression is well-studied in birds. ...
... There are some questions raised by this hypothesis. The BC has sibling aggression (Antonevich & Naidenko, 2013), but only part of the SSBC (Table). However single case of observed sibling aggression in BC does not allow us to conclude if this aggression leads to siblicide. ...
... Moreover, unique traits can determine species-specific patterns of development. In lynx genera early sibling aggression is an important part of kittens' development (Sokolov et al., 1994;Vargas et al., 2005;Antonevich & Naidenko, 2013). Fights occur in 50% of litters with 2-4 kittens in Eurasian lynx (Lynx lynx Linnaeus, 1758) and almost in all litters of Iberian lynx (Lynx pardinus Temminck, 1827) . ...
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In Iberian Lynx Ex situ Conservation: An Interdisciplinary Approach
  • S V Naidenko
  • A L Antonevich
Naidenko S. V. & Antonevich A. L. 2009. Sibling aggression in Eurasian lynx (Lynx lynx). In Iberian Lynx Ex situ Conservation: An Interdisciplinary Approach. Vargas A., Breitenmoser C., Breitenmoser U. (Eds.) Fundación Biodiversidad, Madrid, Spain, pp. 146-155.
Specific fights of young lynxes (Felis lynx, Carnivora, Felidae)
  • V E Sokolov
  • S V Naidenko
  • M A Serbenyuk
Sokolov V. E., Naidenko S. V. & Serbenyuk M. A. 1994. Specific fights of young lynxes (Felis lynx, Carnivora, Felidae). Zoologicheskii Zhurnal 73, 132-138. [In Russian with English summary]