Growth and development of heather voles.

Data on growth and development are presented for eight litters of captive-born Phenacomys intermedius. Neonates from litters of four averaged 2.26 g at birth, significantly heavier than neonates from litters of five (1.96 g). Weights on day one showed a statistically significant decrease of 0.20 g per increase in litter size of one neonate. In general, large litters had lower growth rates. Growth of Phenacomys intermedius can be described by the equation Y = 1.17 + 0.62 X and the geometric growth constant is K = 0.079. Pinnae unfolded at 3.7 days, lower incisors erupted at 7.0 days, and eyes opened at 14.6 days. Data on growth and development are compared to other species of Phenacomys and to other microtines.