Echolocation sounds of hourglass dolphins ( Lagenorhynchus cruciger) are similar to the narrow band high-frequency echolocation sounds of the dolphin genus Cephalorhynchus.

The article offers information a study which examines the similarity of the echolocation sounds of lagenorhynchus cruciger and the narrow band high-frequency echolocation sounds of cephalorhynchus. According to the study, because lagenorhynchus is nested within the genus cephalorhynchus, both are concentrated in a narrow band so-called Narrow Band High Frequency (NBHF). However, controversies over the differences in the sound production mechanisms of dolphins are also mentioned.