SD Rat


The colony history began with a colony of rats established by Robert Dawley around 1925. SD rats are often referred to as "Sprague-Dawley®" Mr. Dawley used both his name and the maiden name, "Sprague", of his wife to create the name of the stock. The colony then went to Sprague Dawley, Inc. in 1945. NIH began a closed colony with animals obtained from Sprague Dawley, Inc. Hilltop Lab Animals, Inc. received animals from NIH in 1984. Through cesarean rederivation, the animals were fostered onto gnotobiotic rats in isolation. Descendants of these animals then became the colonies currently available. All colony histories contain some possibility of inaccuracy. This information is provided to the best of Hilltop's knowledge.
Growth Chart
Blood Chemistries
Viral Antibody Profile
Services Offered
  • Retired Breeders
  • Timed Pregant
  • Untimed Pregnant
  • Littermates
  • Mothers with Litters


The coat color of the rat is albino. The rat is propagated using an outbred breeding system. The colonies, located at Hilltop Lab Animals, Inc., are closed colonies and have been so since 1985. Closed colonies develop qualities causing the rats to be uniquely suited to certain types of research.