Growth studies in Akodon dolores [Rodentia: Muridae] in captivity

Growth processes in Akodon dolores Thomas, 1916 were studied by measuring morphological variables in a captive colony of 1500 specimens. Sex differences were not statistically significant. Most variables fitted to a sigmoid function and showed the same behaviour up to 3 months of age: an acceleration in growth up to the first month, followed by a deceleration up to the third month. Growth variables reached their asymptotic value after the fourth month of age. An exception was the lens weight which continually increased with age without reaching an asymptotic value. The instantaneous growth rates became less than unity at the third month of age, indi­cating that the maximal percentile growth should be before this stage. The latter was corroborated with the body weight increase and body length curves in which the inflexion point was observed at the 1-month stage. In A. dolores this stage is physiolo­gically associated with puberty and in the present study was reached when the animals achieved 40% of their adult body weight. This study is the basis of an age distribution study of A. dolores with a biological foundation.