Cyclorana novahollanidae (photo C Franklin)
Despite a commonly perceived need for water, many species of Australian frogs inhabit regions of the continent which may not receive water for up to several years. These frogs survive periods of drought by ‘aestivating’. Aestivation is a type of dormancy (like hibernation) entered into in response to water and/or food shortages and is typically associated with relatively warm conditions. Aestivating frogs generally burrow underground during the dry season, form a water conserving cocoon and depress their metabolism dramatically. After heavy rains, the frogs return to the surface to mate and feed to replenish fat stores before burrowing back underground to wait out the next dry season.
Cyclorana novahollanidae (photo C Franklin)

Our study animal is the Green Striped Burrowing Frog (Cyclorana alboguttata). This species is found in semi-arid to arid regions of Eastern Queensland and Northern New South Wales. These animals typically spend upwards of 9 months of the year in aestivation. During this time, animals are encased underground in small burrows and they do not eat. Our research has shown that they depress their metabolism by up to 80%, which allows them to survive these periods on their fat alone. Moreover, we have shown that despite being immobile for many months, they do not suffer any significant muscle wastage (a significant problem affecting humans when their limbs are immobilised). We have also shown that despite being without food for extended periods, their digestive systems remains functional which allows them to feed as soon as they emerge from aestivation (again, something humans can not do if they are fasted for any length of time).