Tooth eruption in two agile gibbons (Hylobates agilis)
Makiko Uchikoshi, Tetsuro Matsuzawa
Although the eruption stage of teeth is often used for a quick assessment of maturation in mammals, little is known about tooth-eruption in gibbons in general and specifically about the eruption of permanent teeth. In this study, we present longitudinal data on tooth-eruption in two captive agile gibbons (Hylobates agilis). The eruption of the deciduous dentition started around the age of one week, and was completed around the age of five months. This result was similar to findings of earlier studies on other gibbon species. The eruption of permanent teeth started at the age of 1.4 years and was completed at the age of around 6.6 years. There were individual differences between subjects both in the age at which certain teeth erupted and in the sequence of their eruption. A comparison with data on other primates suggests that ages of individual teeth eruptions in agile gibbons were similar to those of Japanese macaques, but occurred earlier than in chimpanzees and humans. As our gibbon sample is very small, observations on additional individuals are required in order to assess the generality of this result.