Orca Sounds- Recent paper in Animal Behaviour (fwd)

From: pita admininstrator (pita@www1.wheelock.edu)
Date: Tue Dec 19 2000 - 09:59:37 EST


Within-pod variation in the sound production of a pod of killer whales,
Orcinus orca
Patrick J. O. Miller and David E. Bain

ABSTRACT:

Pod-specific calling behaviour of resident killer whales has been shown
to include: discrete call types not shared among pods, different
production rates of shared call types, and differences in the detailed
structure of shared call types. To investigate the mechanisms leading to
pod-specific calling, we compared the repertoire and structure of calls
produced by three different matrilineal units within the same pod, and
described call features encoding matrilineal-unit distinctiveness. The
three matrilineal units had different production rates of shared calls,
including one call type used almost exclusively by one matrilineal unit.
Cross-validated discriminant function analyses revealed matrilineal-unit
distinctive structure in five of the six shared call types examined,
with duration of the terminal component being the most distinctive
feature for all call types containing a terminal component. Calls
generally consist of low- and high-frequency components that may follow
different time-frequency contours. In our sample, a particular
high-frequency contour was consistently paired with a particular
low-frequency contour, both contours had roughly equal overall
variability, and each contained independent matrilineal-unit distinctive
information. The only call type that did not differ structurally between
matrilineal units is reportedly used more in interpod meetings than in
intrapod contexts. The differences in calling behaviour between
matrilineal units were similar in form to previously described
differences between pods, although more subtle. These results suggest
that pod-specific calling behaviour in resident killer whales arises
primarily as a consequence of accumulated drift or divergence between
highly cohesive matrilineal units as they gradually separate into
different pods.

Copyright 2000 The Association for the Study of Animal Behaviour

Correspondence: P. J. O. Miller, WHOI, MS#34, Woods Hole, MA 02543,
U.S.A. (email:pmiller@whoi.edu).
D. E. Bain is now at Six Flags Marine World Vallejo, Vallejo, CA 94589,
U.S.A.

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<html>
Within-pod variation in the sound production of a pod of killer whales,
<i>Orcinus orca</i>
<br>Patrick J. O. Miller and David E. Bain
<p>ABSTRACT:
<p>Pod-specific calling behaviour of resident killer whales has been shown
to include: discrete call types not shared among pods, different production
rates of shared call types, and differences in the detailed structure of
shared call types. To investigate the mechanisms leading to pod-specific
calling, we compared the repertoire and structure of calls produced by
three different matrilineal units within the same pod, and described call
features encoding matrilineal-unit distinctiveness. The three matrilineal
units had different production rates of shared calls, including one call
type used almost exclusively by one matrilineal unit. Cross-validated discriminant
function analyses revealed matrilineal-unit distinctive structure in five
of the six shared call types examined, with duration of the terminal component
being the most distinctive feature for all call types containing a terminal
component. Calls generally consist of low- and high-frequency components
that may follow different time-frequency contours. In our sample, a particular
high-frequency contour was consistently paired with a particular low-frequency
contour, both contours had roughly equal overall variability, and each
contained independent matrilineal-unit distinctive information. The only
call type that did not differ structurally between matrilineal units is
reportedly used more in interpod meetings than in intrapod contexts. The
differences in calling behaviour between matrilineal units were similar
in form to previously described differences between pods, although more
subtle. These results suggest that pod-specific calling behaviour in resident
killer whales arises primarily as a consequence of accumulated drift or
divergence between highly cohesive matrilineal units as they gradually
separate into different pods.
<p>Copyright 2000 The Association for the Study of Animal Behaviour
<p>Correspondence: P. J. O. Miller, WHOI, MS#34, Woods Hole, MA 02543,
U.S.A. (email:pmiller@whoi.edu).
<br>D. E. Bain is now at Six Flags Marine World Vallejo, Vallejo, CA 94589,
U.S.A.
<br>&nbsp;</html>

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