The Sprague Dawley rat is an outbred multipurpose breed of albino rat used extensively in medical research.
Its main advantage is its calmness and ease of handling.
This breed of rat was first produced by the Sprague Dawley farms (later to become the Sprague Dawley Animal Company) in Madison, Wisconsin in 1925. The average litter size of the Sprague Dawley rat is 11.0.
These rats typically have increased tail to body length ratio compared with Wistar rats.