F. Harvey Pough


Article may be found at: In the families Agamidae, Gerrhosauridae, Iguanidae, and Scincidae, species that weigh more than 300 g are almost all herbivores, whereas those weighing less than 50-100 g are carnivores. Juveniles of large herbivorous species tend to be carnivorous until they reach body weights of 50-300 g. Diet is compared to metabolic expenditure in these lizards. Although smaller animals have higher weight-specific metabolic rates, the greater total metabolicrate of larger animals requires a greater caloric intake. Juvenile animals and species of small body size are primarily insectivorous. It is postulated that larger animals of these families are unable to get caloric demands on a diet of insects, have no practical alternative animal prey, and rely instead on vegetation. The families Anguidae, Chamaeleontidae, Helodermatidae, Teiidae, and Varanidae do not include herbivorous species, although each family has species that weigh more than 300 g. Morphological, ecological, and physiological specializations in these families account for the absence of herbivorous species. For an unspecialized lizard, evolution of large body size both requires and permits an herbivorous diet.

Publication Date



This study was supported by NSF Grant GB 18,985. Note: imported from RIT’s Digital Media Library running on DSpace to RIT Scholar Works in February 2014.

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Department, Program, or Center

Thomas H. Gosnell School of Life Sciences (COS)


RIT – Main Campus