[MARMAM] 2 articles on flipper rubbing behaviour in bottlenose dolphins

Mai SAKAI mais at bu.iij4u.or.jp
Thu Jun 7 21:13:56 PDT 2007


Dear All,

We would like to inform you the following 2 articles have been published in
behavioural brain research and marine mammal science.
For PDF reprints, please contact Mai Sakai at mai at ori.u-tokyo.ac.jp.

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Sakai, M., Hishii, T., Takeda, S. & Kohshima, S. 2006. Laterality of flipper
rubbing behaviour in wild bottlenose dolphins (Tursiops aduncus): Caused by
asymmetry of eye use? Behavioural Brain Research, 170(2), 204-210.
http://dx.doi.org/10.1016/j.bbr.2006.02.018

Abstract
To determine whether wild Indo-Pacific bottlenose dolphins (Tursiops
aduncus) at Mikura Island, Japan, show asymmetry of eye or flipper use
during a social behaviour, we investigated the laterality of flipper-to-body
(F–B) rubbing, in which one dolphin (“rubber”) rubs the body of another
(“rubbee”) with its flipper. We analysed 382 episodes of video-recorded
F–B rubbings performed by identified individuals (N= 111 rubbers). F–B
rubbing was conducted significantly more frequently with the left flipper
than with the right flipper. The duration of F–B rubbings was also
significantly longer with the left flipper than with the right flipper. Of
20 dolphins, nine individuals showed significant left-side bias as the
rubber in this behaviour, whereas no dolphins showed significant right-side
bias. The results indicate a population-level left-side bias of the rubber
in F–B rubbing. An analysis of the swimming configurations during this
behaviour suggests that the asymmetry in F–B rubbing was caused not only by
the laterality of the rubber, but by a preference for use of the left eye in
both dolphins during this behaviour. Dolphins used the left eye
significantly more frequently than the right eye during the inquisitive
behaviour, while they showed no significant bias in flipper use during the
object-carrying behaviour. These facts also suggest that the asymmetry of
F–B rubbing is caused by the preference for using the left eye. Significant
left-side bias was observed only in F–B rubbings initiated by the rubbee, in
which the rubbee determined its position during this behaviour. This
suggests that this behavioural asymmetry was enhanced by the rubbees
choosing the left side of the rubber to ensure better and longer rubs.

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Sakai, M., Hishii, T., Takeda, S. & Kohshima, S. 2006. Flipper rubbing
behaviors in wild bottlenose dolphins (Tursiops aduncus). Marine Mammal
Science, 22(4), 966-978.
http://www.blackwell-synergy.com/doi/abs/10.1111/j.1748-7692.2006.00082.x

Abstract
“Flipper rubbing” behavior was quantitatively analyzed in wild
Indo-Pacific bottlenose dolphins (Tursiops aduncus) around Mikura Island,
Tokyo, Japan. We observed two types of flipper rubbing: (1) F-B rubbing; one
dolphin (Rubber) rubbed its flipper over various parts of a partner’s
(Rubbee) body, and (2) F-F rubbing; both dolphins rubbed each other’s
anterior flipper edge in alternating shifts. F-B rubbings tended to be
initiated by the Rubbee and were terminated by the Rubber. The Rubbee often
moved actively its body part that was in contact with the Rubber’s flipper,
and assumed side-up, upside-down, or other postures while the Rubber
remained horizontal in most cases. These facts suggest that the Rubbee
engaged in F-B rubbing more actively than the Rubber, and might receive some
benefit from the frictional contact during F-B rubbing. Dolphins often
switched their roles as Rubber and Rubbee between episodes of flipper
rubbing bout. Adults and subadults exchanged F-B rubbing and F-F rubbing
most often with individuals of the same sex in the same age class. F-B
rubbing was frequent in mother-and-calf dyads. Our results suggest that
flipper rubbing is an affiliative behavior which could be a quantitative
measure of social relationships among individuals of this species in future
studies.

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Mai SAKAI
mai at ori.u-tokyo.ac.jp
International Coastal Research Center,
 Ocean Research Institute, The University of Tokyo,
2-106-1 Akahama, Otsuchi, Iwate 028-1102, Japan
phone:+81-193-42-5611, fax: +81-193-42-3715




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