The role of behavioural data on the survival of schistosomiasis vector snails under molluscicide treatment was reviewed. It was seem that those modes of behaviour such as retracting into shell, avoiding dry places, crawling out of water, burrowing and avoiding toxic agents have been considered to be of protective value, but the evidence availabel has not provided much information about the nature of the mechanisms involved their survival significance. The necessity of an ethological approach for a proper description and analysis of the relevant aspects was stressed.