EN
Energy balance and body mass changes were studied in non-reproducing adult eastern hedgehogs Erinaceus concolor (Martin, 1838) during an 8-day feeding trial. The amount of energy consumed by the hedgehogs that maintained constant body mass averaged 0.74 kJ x g_1 x day-1. The energy equivalent of body mass loss amounted to 15.12 kJ x g-1, and that of body mass gain was 25.18 kJ energy consumed x g~ . If the energy contents of body mass gained and lost were the same, biomass production efficiency was 72.2%.