[MARMAM] New publication on dolphin echolocation
Adam A. Pack
pack at hawaii.edu
Mon Jan 22 22:07:45 PST 2007
For your interest, we have just published the
following article on dolphin echolocation:
Branstetter, B. K., Mevissen S. J., Pack, A. A.,
Herman, L. M., Roberts, S. R., and Carsrud, L. K.
(2007). Dolphin (Tursiops truncatus) echoic
angular discrimination: Effects of objects
separation and complexity. Journal of the
Acoustical Society of America, 121, 626-635.
Summary of article
A bottlenose dolphin was tested on its ability to
echoically discriminate horizontal angular
differences between arrays of vertically oriented
air-filled PVC rods. The blindfolded dolphin was
required to station in a submerged hoop 2 radial
m from the stimuli and indicate if an array with
two rods (S+) was to the right or the left of a
single rod (S-). The angular separation between
the two rods (thetaw) was held constant within
each experiment while the angle between the S+
and the S- stimuli (thetab) varied to produce
angular differences (Deltatheta=thetab-thetaw)
ranging from 0.25 to 4°. In experiment I, thetaw
was maintained at 2° and in experiment II, thetaw
was maintained at 4°. Resulting 75% correct
thresholds (method of constant stimuli) were 1.5
and 0.7°, respectively. The two main findings of
this study are: (1) decreasing the number of
targets does not aid in localization, and (2)
increasing the space between the rods enhances
localization. Taken as a whole, the experiments
suggest dolphins have a well-developed ability to
resolve spatial information through sonar.
Reprint pdfs may be obtained from Brian
Branstetter at branstet at hawaii.edu or from Adam
Pack at pack at hawaii.edu.
Wishing you all a happy, healthy, and peaceful 2007,
Adam A. Pack, Ph.D.
Vice President and Research and Education Program
Manager, The Dolphin Institute
Affiliate Graduate Faculty, University of Hawaii at Manoa
P.O. Box 700694
Kapolei, HI 96709
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