BREEDING OF THE WATER RAT (NECTOMYS SQUAMIPES) IN THE LABORATORY

The water rat, Nectomys squamipes, is reported as a natural host of Sc histosoma mansoni in Brazil. This paper presents some reproductive, gr owth and developmental data, and laboratory management of a breeding p rogramme for N. squamipes. The colony was derived from animals capture d 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 o f 4 and 5. Sex ratio at birth and at weaning was not significantly dif ferent from the expected ratio of 1:1. There were no significant diffe rences between mean body weights at birth for males and females. The m inimum age for weaning was between 20-25 days. The growth curves of bo dy weight, head-body length and tail length, for both sexes, comprise at least three linear segments representing different phases of approx imately constant growth rates. Facilities for colony maintenance and i ts potential for use as experimental model are reported.