and is notably the first rat developed to serve as a model organism at a time when laboratories primarily used the common house mouse (Mus musculus). More than half of all laboratory rat strains are descended from the original colony established by physiologist Henry Donaldson, scientific administrator Milton J. Greenman, and genetic researcher/embryologist Helen Dean King.[33][34]
The Wistar rat is currently one of the most popular rats used for laboratory research. It is characterized by its wide head, long ears, and having a tail length that is always less than its body length. The Sprague Dawley rat and Long-Evans rats were developed from Wistar rats. Wistar rats are more active than others like Sprague Dawley rats. The Spontaneously hypertensive rat and the Lewis rat are other well-known stocks developed from Wistar rats.