Most biologists would agree that understanding the factors that influence gene flow among populations is important, because population connectivity is critical to effective conservation and management as well as to issues such as disease transmission and the degree of local adaptation. Nonetheless, our understanding of the mechanistic determinants of gene flow remains abysmally limited for many types of organisms. Predictably, some of the biggest gaps involve animals that are rare, secretive, and difficult to collect or handle — and thus, remain relatively unstudied for other traits as well. Large venomous snakes have long provided a classic example of such an under-studied group, but the situation has changed dramatically over recent years. The study by Clark et al. in this issue builds upon our increasingly sophisticated understanding of snake behaviour, to interpret patterns of gene flow in the light of our emerging knowledge of snake behavioural ecology.