Subject: Abstract: Lagenorhynchus / Phocoena interaction (fwd)

Mike Williamson (pita@www1.wheelock.edu)
Thu, 18 Jun 1998 15:18:42 -0400 (EDT)

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
                      J. Michael Williamson
Principal Investigator-WhaleNet <http://whale.wheelock.edu>
                   Associate Professor-Science
  Wheelock College, 200 The Riverway, Boston, MA 02215
             voice: 617.734.5200, ext. 256
            fax:    617.734.8666, or 978.468.0073

          "Mother, Mother Ocean, I have heard your call,
   Wanted to sail upon your waters, since I was three feet tall"
                        Jimmy Buffett
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---------- Forwarded message ----------
Date: Thu, 18 Jun 1998 10:40:12 -0300
From: Robin W Baird <rwbaird@is.dal.ca>
Reply-To: Marine Mammals Research and Conservation Discussion
     <MARMAM@UVVM.UVIC.CA>
To: MARMAM@UVVM.UVIC.CA
Subject: Abstract: Lagenorhynchus / Phocoena interaction


Baird, R.W. 1998. An interaction between Pacific white-sided dolphins
and a neonatal harbor porpoise. Mammalia 62: 129-134

Summary

An interaction involving two Pacific white-sided dolphins and a
neonatal harbor porpoise was observed in eastern Haro Strait, WA, in
1994, and lasted for at least five hours. On a number of occasions
one of the dolphins was observed holding the porpoise's flipper in
its mouth and dragging the porpoise through the water. Both dolphins
were observed to occasionally leap on top of the porpoise as it swam
at or near the water's surface. During close approaches of the
porpoise to our vessel, one or the other dolphin quickly swam between
the porpoise and our boat, and turned away in such a fashion as to
force the porpoise away from the boat. Two and one half hours into
the observation, a decision was made to capture the porpoise, and the
porpoise was captured 2.5 hours later, surviving for five days in
captivity. Despite being dragged by its flipper, the porpoise only
had superficial skin abrasions on its flippers when captured. Five
wounds, consistent with bites, were found on the caudal peduncle. No
other trauma was noted, and cause of death was determined to be
bacterial pneumonia. Although Pacific white-sided dolphins previously
have been reported associating with at least 10 different species of
cetaceans, associations with harbor porpoises do not appear to have
been previously published. This observation is the first reported of
an apparently non-predatory interspecific interaction involving a
lone cetacean neonate. Possible causes of the interaction are
discussed, including epimeletic behavior, aggressive behavior due to
competition, predation or kleptoparasitism, and object-oriented play.
In many ways the observations appear similar to object-oriented play
(or non-mutual, interspecific play) behavior, with, in this case, the
"object" being the harbor porpoise. The function(s) or beneficial
effects of "play" in such cases are usually related to physical
training or skill development, and this is certainly a possibility in
this case.

Reprints are available from the author: rwbaird@is.dal.ca

==========================================================
Robin W. Baird, Ph.D.
Biology Department, Dalhousie University, 1355 Oxford St.,
Halifax, Nova Scotia B3H 4J1 Canada
Phone (902) 494-3723
Fax (902) 494-3736
e-mail: rwbaird@is.dal.ca
http://is.dal.ca/~whitelab/index.htm