Active sharing of a novel, arbitrary innovation in captive cotton-top tamarins?

Most cultural behaviours in primates stem from innovations that are beneficial since they provide access to food or comfort. Innovations that are seemingly purposeless and arbitrary, and nevertheless spread through a social group, are rarer but particularly relevant to understanding the evolutionary origin of culture. Here, we provide an anecdotal report of a series of non-instrumental woodchip manipulation and modification events in captive cotton-top tamarins. Intriguingly, woodchips were preferentially manipulated in a position that was readily visible to a partner in a different enclosure, and the innovation apparently spread to other individuals. Together, this suggests that the arbitrary innovation was actively shared with a conspecific, which is consistent with the pattern of transmission of another arbitrary innovation in cotton-top tamarins, namely stick-weaving.