The two matrilines, I17 and I18, have been encountered only 48 times over the 25-year-long study. They where together on about one-third of these encounters.
It is a burgeoning group, however, increasing from 5 whales in 1975 to an 20 in 2007.
Acousticaly,I18 pod is very closely related to I1 and I2 pods
Source: Killer whales Second edition
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Discrete calls
We don't exactly what the repertoire of I18 pod of descrete calls is. Probably it is the same as I1 en I2 pod.
If so the repertoire of the I18 pod consists of the following 13 discrete calls : N1ii, N1iv, N3, N5i, N5ii, N7ii, N7iii, N8iii, N8iv, N12, N16iii, N16iv, and N20
There are no calls recorded of the I18 pod
