Record of nesting material collection behavior in Metachirus myosuros (Didelphimorphia: Didelphidae)

Records of collecting nest building material lack descriptions or are missing for most didelphids. We describe the tail use in this behavior in Metachirus myosuros on Atlantic Rainforest and compare it with similar behaviors reported for other didelphids. The behavior described here is like those reported for other closely related species, and likely can be traced at least to the last common ancestor of Didelphini and Metachirini (~15 Maa). However, scarcity of data on other taxa makes it impossible to state that this behavior was already present in the start of the Didelphidae clade.