Mobile phone data allows for the direct observation of population-scale mobility. In this study, the movements of populations in Senegal in 2013 were quantified using anonymised mobile phone data. Movement patterns among populations groups were extracted and visualised, which resulted in a series of mobility profiles from different regions of Senegal. These mobility profiles were compared with agricultural cycles and livelihoods of each region. Results of this analysis showed that for vulnerable population groups, changes in mobility patterns could indicate changes in livelihoods or coping strategies, or exposure to new shocks. Monitoring such changes in vulnerability in real-time could be a powerful humanitarian early warning mechanism for informed decision-making and rapid response.