Energetic costs of digestion in Australian crocodiles

C. M. Gienger, Christopher R. Tracy, Matthew L. Brien, S. Charlie Manolis, Grahame J W Webb, Roger S. Seymour, Keith A. Christian

    Research output: Contribution to journalArticlepeer-review


    We measured standard metabolic rate (SMR) and the metabolic response to feeding in the Australian crocodiles, Crocodylus porosus and C. johnsoni. Both species exhibit a response that is characterised by rapidly increasing metabolism that peaks within 24h of feeding, a postfeeding metabolic peak (peak V̇O2) of 1.4-2.0 times SMR, and a return to baseline metabolism within 3-4 days after feeding. Postfeeding metabolism does not significantly differ between species, and crocodiles fed intact meals have higher total digestive costs (specific dynamic action; SDA) than those fed homogenised meals. Across a more than 100-fold range of body size (0.190 to 25.96kg body mass), SMR, peak V̇O2, and SDA all scale with body mass to an exponent of 0.85. Hatchling (≤1 year old) C. porosus have unexpectedly high rates of resting metabolism, and this likely reflects the substantial energetic demands that accompany the rapid growth of young crocodilians.

    Original languageEnglish
    Pages (from-to)416-421
    Number of pages6
    JournalAustralian Journal of Zoology
    Issue number6
    Publication statusPublished - 2012


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