ENERGETIC COSTS OF ACTIVITY BY LIZARDS IN THE FIELD

1. The available data related to the activity energetics of lizards in the field were collated with respect to three indices of activity ene rgetics: the ecological cost of transport (ECT) expressed as a percent age of the total energy, the proportion of total energy used in all fa rms of activity (%AR), and the sustained metabolic scope (SusMS), defi ned as the ratio of the total energy expenditure to the total resting metabolism 2. The ECT values of lizards ranged from 3 to 36% with five of 11 species having values >20%, The percentage AR ranged from 23 to 80% for lizards during active seasons. with most species having value s > 50%. The SusMS ranged from 1.1 to 5.1. 3. Values of ECT are higher for lizards than for mammals, in part because the costs of maintenanc e metabolism are higher in mammals. 4. The percentage AR and SusMS val ues of mammals are higher than those of lizards. 5. It follows from th e previous two points that the proportion of the total daily energy th at is expended in non-locomotory activities is disproportionately high er in mammals compared with lizards. 6. The energy expended in locomot ion is a significant portion of the energy budget of lizards, This is generally true for all seasons in which then is activity.