Breeding of the water rat (Nectomys squamipes) in the laboratory.

The water rat, Nectomys squamipes, is reported as a natural host of Schistosoma mansoni in Brazil. This paper presents some reproductive, growth and developmental data, and laboratory management of a breeding programme for N. squamipes. The colony was derived from animals captured at Sumidouro, Rio de Janeiro state. The animals' diploid number was 56, conception rate was 66.7% and gestation period was 30 days. Litter size ranged from 1 to 6, with a mean of 4.1 (SD +/- 1.2) and a mode of 4 and 5. Sex ratio at birth and at weaning was not significantly different from the expected ratio of 1:1. There were no significant differences between mean body weights at birth for males and females. The minimum age for weaning was between 20-25 days. The growth curves of body weight, head-body length and tail length, for both sexes, comprise at least three linear segments representing different phases of approximately constant growth rates. Facilities for colony maintenance and its potential for use as experimental model are reported.