SpragueDawley

Sprague-Dawley rats are a widely used outbred stock of albino laboratory rats (Rattus norvegicus) developed in the United States in the 1920s by researchers Sprague and Dawley. They have become one of the most common rat models in biomedical research and are distributed by major vendors worldwide.

Physically, Sprague-Dawley rats are white with pink eyes and are known for a calm temperament, rapid growth, and high fertility. They retain greater genetic diversity than inbred strains, which can be advantageous for studies requiring a more representative genetic background. Typical litter sizes range from about six to twelve pups, and adulthood is reached relatively quickly, aiding rapid experimentation. Under standard laboratory conditions, their lifespan is roughly 2 to 3 years.

Uses of Sprague-Dawley rats span pharmacology, toxicology, oncology, neuroscience, and metabolism studies. Their robust physiology and docile nature make them suitable for surgical training and a wide range of physiological measurements. They are also commonly used as controls or general-purpose models in comparative studies.

Notes on genetics and sourcing: Because they are outbred, genetic variation among individuals is higher than in inbred strains, which can influence experimental outcomes. Substrains from different suppliers may exhibit drift in genetic makeup over time. Sprague-Dawley rats remain widely available from major commercial vendors and research colonies worldwide.