A Long Term Study of the Tooth Replacement Phenomenon in the Young Green Iguana, Iguana iguana

Abstract

A study using 11 young green iguanas, Iguana iguana examined the growth of the animals, changes in the wave replacement of teeth, the increasing size of the teeth, and the posterior migration of tooth positions over a period of 2.7 years. The results supported the view that tooth replacement is closely related to growth. The teeth were measured regularly and demonstrated a smooth increase in width as the lizards grew. The tooth positions were found to migrate posteriorly thereby providing adequate space for the ever larger teeth replacing their smaller predecessors. These observations suggested that the wave replacement of teeth allows for adequate growth of the dentition in length and height to maintain teeth of a size in proportion to the overall size of the individual. The teeth of most non-mammalian vertebrates are continuously replaced throughout life. Each new tooth is ini- tiated on the lingual side of the jaw. As it grows it passes toward the oral cavity where it functions for a few months be-