We are currently between Ice Ages, in the Holocene. In Britain, the previous geological time period, the Pleistocene (Ice Age), was interspersed with a series of warm (interglacial) periods in which warm-adapted mammals such as Hippopotamus Hippopotamus amphibius, Barbary Ape Macaca sylvana and Spotted Hyaena Crocuta crocuta migrated north through Europe.