Transfer of fermentative microbes between generations in a herbivorous lizard.

Iguana iguana is herbivorous throughout life and utilizes a microbial fermentation system in the elaborated hindgut to break down plant cell walls. Iguanas reared in captivity grew more slowly than wild hatchlings and failed to develop the same complex populations of fermentative microbes. Captive hatchlings fed fresh fecal material from an adult iguana acquired the complex microflora and grew as rapidly as wild hatchlings. In the field, hatchlings actively associated with adults during the first weeks of life and obtained the complex microflora during this time. Acquisition of the fermentative microflora by neonatal iguanas apparently requires direct contact with older conspecifics.