A pair of recent issues of Science plonked into my mail box this week. Among the items that caught my eyes was an exciting brief communication in Science shows a rare example of what appears to be fossil evidence of behaviour. These are Waptia-like arthropods from the Lower Cambrian, which appear to have been preserved while engaged in some form of processionary behaviour. Unlike known present day processionary arthropods, these chains of individuals appear to be physically linked - you can see in the figure that there is overlap between an individual's carapace and the preceding individual's telson. The authors propose the chains reflect migratory behaviour rather than feeding or reproduction.