Marine mammals equipped with recording devices can help to overcome the practical challenges of collecting year-round physical data in the Southern Ocean (see M. C. Kennicutt II et al. Nature 512, 23–25; 2014).

Data collection using satellite remote sensing or surface research vessels, for instance, is limited to the short summer period for access to high latitudes or to the northerly margins of winter sea ice.

By contrast, small oceanographic sensors worn by seals can provide high-resolution oceanographic profiles from Antarctica throughout the winter (see, for example, F. Roquet et al. Scientific Data, in the press). The data can be used to study and map ocean fronts and to monitor the annual formation and growth rate of sea ice (J.-B. Charrassin et al. Proc. Natl Acad. Sci. USA 105, 11634–11639; 2008).

Data derived using seals can help us to predict rapid changes and their effects in the Southern Ocean. This would give the global community time to develop adaptation policies.