Pythons are found over much of the Australian mainland and comprise a group of animals that have been poorly studied in the field to date. In this study, I investigated the biology of some python species (Morelia spilota variegata, M.s.bredli, Antaresia childreni, A. stimsoni and Liasis fuscus) that vary in habitat, size, climate and prey type using ecophysiological methods such as laboratory metabolism and energy expenditure in the field using isotopic techniques. With such obvious variation in life history variables between species, some aspects of their biology are inferred from experiments on a single species. This was due mostly to the logistical problem of obtaining sufficient numbers of each species for both field and laboratory investigation.