This article is from the WSSF 2012 AFRMA Rat & Mouse Tales news-magazine.
By Karen Robbins
The photo above shows the size difference between
a full grown male rat vs. a full grown large male
It also shows how the Russian Blue rat color is the same as the Blue
mouse color. You can read more about the
blue gene in
rats, a.k.a. Russian Blue, in these research articles:
An independent recurrence of the blue mutation in the Norway rat and a blue-black mosaic.Curtis, M. R.; Dunning, W. F. Journal of Heredity, 1940 Vol. 31 pp. 219–222.
Shorter Articles and Discussion, Linkage Studies in the Rat.E. Roberts and J. H. Quisenberry. The American Naturalist, Vol. 70, No. 729, Jul.–Aug. 1936, pp. 395–399.
Russian Blue Self Standard rat and Blue Self Standard mouse (mouse is leaden gene ln, mouse dd and ln look identical), both owned and bred by Karen Robbins.