Written and maintained by CASRAI Editorial Board
Last updated
Wistar rats are an outbred, albino stock of the laboratory rat (Rattus norvegicus) that traces to work around 1906 associated with the Wistar Institute, and they are one of the most widely used general-purpose rat models. “Wistar” names a stock, not a single inbred line, so substrain names matter.
Definition and scope: what is a Wistar rat?
A Wistar rat (also written “Wistar rat” in the singular) is an outbred albino laboratory rat. Outbred means animals are bred as a genetically variable population rather than as an inbred line of near-identical siblings. The eLife review “The Norway rat, from an obnoxious pest to a laboratory pet” (2020) lists Wistar as outbred and albino, dated 1906, and describes it as among the most popular general multi-purpose rat models, used in studies of infectious disease, aging and surgical models.
This page is general reference for researchers and lab staff. It is not husbandry guidance, and animal work always falls under institutional oversight such as the IACUC.
Origin: how the Wistar stock came about
The same eLife review reports that Henry Herbert Donaldson brought four pairs of albino rats with him when he became director of the Wistar Institute, intending to standardize the albino rat as a universal biomedical model. In 1912 the Institute began supplying laboratory rats to other research institutions. Because the stock was distributed widely, many later strains and vendor colonies descend from it. Sources differ on the exact place of origin: the eLife table gives the Wistar Institute, Philadelphia, while a 2025 Experimental Animals paper describes the origin as the University of Chicago, 1906. This page therefore ties the stock to Donaldson’s work and the 1906 date without asserting one site.
How the name is used in practice: stock versus substrain
Papers and vendor catalogues rarely say only “Wistar”. Substrain designations record where a colony was maintained. The 2025 Experimental Animals paper (Hematological and biochemical characterization of aging farm male rat strains) gives one example: the RccHan:WIST substrain was established by the Zentralinstitut fuer Versuchstierzucht (ZfV) in Hannover in 1989, and moved from Harlan Sprague-Dawley to RCC Ltd (Itingen, Switzerland) in 2004. It is described there as commonly used in pharmaceutical development in Europe. Because colonies are outbred and maintained separately, results from “Wistar” rats from different sources are not automatically interchangeable, so reports should name the exact stock designation and supplier.
The Wistar family and related strains
The table below uses only the strain list in the eLife review (Table 1).
| Stock or strain | Type | Origin (as listed) | Described use |
|---|---|---|---|
| Wistar | Outbred, albino | The Wistar Institute, Philadelphia (1906) | General multi-purpose; infectious disease, aging, surgical models |
| Wistar Han | Outbred, albino | Zentralinstitut fuer Versuchstierzucht, Hannover | General multi-purpose; popular in preclinical safety assessment, aging, oncology, surgical models |
| Wistar Kyoto | Outbred, albino | Kyoto School of Medicine | Normotensive controls for the spontaneous hypertensive line |
| Sprague Dawley | Outbred, albino | Sprague-Dawley farms, Madison, Wisconsin (1925); derived from a hybrid Hooded male and a female Wistar | Widely used general-purpose stock |
| Lewis | Inbred | Developed by Margaret Lewis from Wistar rats in the early 1950s | Inbred line derived from Wistar stock |
The same review notes that the inbred Brown Norway rat came from a wild-caught colony kept at the Wistar Institute in the 1930s, so it is associated with the Institute but is not a Wistar derivative.
Where it matters for labs and study design
Choice of stock can change what a study shows. In the 2025 Experimental Animals comparison of F344, Sprague Dawley and RccHan:WIST aging males, chronic progressive nephropathy was relatively less prominent in Wistar, Long-Evans and Brown Norway rats than in Sprague Dawley and F344, with males more predisposed. Another sourced difference: juvenile Wistar rats initiate fewer playful attacks than Fisher 344 rats (Schneider 2014, cited in the eLife review). These are examples of why a methods section should state the stock, and why control animals should come from the same stock and source as treated animals. The mouse equivalents of this issue are covered in C57BL/6 and NSG mice; for the regulatory context see animal research ethics and the research animal definition.
Common misunderstandings
- “Wistar” is not an inbred strain. It is outbred; Lewis is the inbred line derived from it.
- Sprague Dawley is not unrelated. The eLife table describes it as derived from a hybrid Hooded male and a female Wistar.
- Wistar, Wistar Han and Wistar Kyoto are different stocks. Each has its own origin and typical use in the table above.
- Brown Norway is not a Wistar strain, despite the Wistar Institute connection.
FAQ
What are Wistar rats used for?
The eLife review describes them as popular general multi-purpose models, with studies of infectious disease, aging and surgical models given as examples.
Is a Wistar rat inbred or outbred?
Outbred. It is an albino stock bred as a genetically variable population.
What is the difference between Wistar and Sprague Dawley rats?
Both are outbred albino stocks. Sprague Dawley (Madison, Wisconsin, 1925) was derived from a hybrid Hooded male and a female Wistar. In the 2025 aging comparison, Wistar rats were relatively more resistant to chronic progressive nephropathy than Sprague Dawley.
What does RccHan:WIST mean?
It designates a Wistar substrain established by ZfV Hannover in 1989 and later maintained at RCC Ltd (Itingen, Switzerland) from 2004, per the 2025 Experimental Animals paper.
Sources
- “The Norway rat, from an obnoxious pest to a laboratory pet,” eLife 2020, PMC6968928 (read 2026-11-07).
- “Hematological and biochemical characterization of aging farm male rat strains,” Experimental Animals 2025, PMC11742475 (read 2026-11-07).
