Locomotory energetics in a marsupial (Antechinomys spenceri) and a rodent (Notomys alexis).

Steady state oxygen consumption was compared in a rodent Notomys alexis and a marsupial Antechinomys spenceri. The marsupial was found to diverge from predicted eutherian energic patterns. N. alexis appears to use energy storage as a significant part of the step cycle before becoming bipedal. Aerobic scope and heat storage during running are similar in both species.