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Figure 4.2. Whistles used by allied male bottlenose dolphins. (A) Average frequency contours of the two most commonly used whistles for three allied males over
four years. (B) Multidimensional scaling of whistles for each male. Individuals noted
by different symbols. Note that the scatter in multidimensional space is reduced over
time, indicating acoustic convergence among individuals. (From Smolker and
Pepper 1999. Reprinted with permission from Blackwell Wissenschafts-Verlag
Berlin, GmgH.)