Evidence from sperm whale clans of symbolic marking in non-human cultures

Symbolic marking is a hallmark of human cultures, but quantitative evidence for nonhuman animal cultures is comparatively limited. We show evidence that certain acoustic communication signals—"identity codas"—function as symbolic markers of cultural identity among Pacific Ocean sperm whale clans. Within clans, identity and nonidentity coda usage shows similar patterns of stability over geographic space, but between-clan similarity in identity coda usage decreases with increasing spatial overlap. The distribution of sperm whale clans—with multiple cultural groups that vary widely in ranging, are unevenly distributed, and frequently overlap along a latitudinal gradient—resembles that of human ethnolinguistic groups. These findings demonstrate how culture can structure and fortify segmentation of animal populations and reveal similarities between human and nonhuman cultures.