Being smart makes stressed snails drop a grade.

Sometimes life is just too stressful. Whether you’re a freshwater snail struggling to breathe in a dwindling puddle or a student facing an assessment that could change your future, it can be hard to form memories when the pressure is on; even the smartest can struggle. ‘We have been exploring how stress alters both memory formation and the ability to recall memory for a number of years’, says Ken Lukowiak from the University of Calgary, Canada, who is intrigued by how the humble pond snail (Lymnaea stagnalis) forms memories. Having recently discovered a ‘smart’ colony of pond snails at White Sand Lake in Saskatchewan that learn quickly (after just one training session) to keep their breathing tubes closed when immersed in deoxygenated water – compared with ‘average’ snails, which require multiple training sessions before they get the point – Lukowiak wondered how resilient the ‘smart’ Saskatchewan snails’ memories would be when they experienced a snail-scale shock.