This simple experiment highlights the importance of shelter for survival. Using our special equipment each group of pupils collects a range of materials from around the nature reserve that they consider to have good thermal qualities. We then test their selection by constructing nests that must keep our pretend mice warm. The temperature of each mouse is recorded and noted down. All of the mice can then hide away in their nests, all but one . . . our Pelham 'silly mouse' stays out of his nest. After and hour or so we test the temperature of each mouse and can then declare whose nest is best!