A new study has shown for the first time that when sandhoppers want to enter a period of deep sleep each winter they have the means through which to increase the magnesium levels in their bodies — in some instances more than doubling them. Essentially acting as a natural narcotic, the magnesium puts the sandhopper into a torpid state and this enforced rest means that the creatures can stay hidden in burrows up to 30cm beneath the beach surface, to some extent buffered from wintry conditions.