The answer is rodents. Rats have a long account in medical
research: they were the first mammalian class exactly tame to be used in the
laboratory.
Records going
back to the 1850s show these animals were came from those bred by rat fanciers who
collected them for their sole coat colors and behavioral features.
The achievement of the rat in investigation today has been related
to the Wistar Institute in
America and their growth of the Wistar albino strain.
