Young green iguanas (example pictured here) are unable to digest plants—the main component of their diet. For this they depend upon bacteria, which they quickly gather by eating the microbe-laden droppings of adult iguanas. This vital process is enhanced by the social behavior of young iguanas who hang out in a large group or rookery, their mothers having nothing more to do with their young after depositing them as eggs in nests in the sand.
For more on green iguana behavior watch “I Contain Multitudes”
This young green iguana was photographed in a reptile shelter in Germany.
Igor Siwanowicz, PhD, HHMI Janelia Farm Research Campus