Long Evans Outbred Rat Model
Live production of this model has ceased. This webpage is retained for historical reference, but this model is not available from Taconic.

  • Model #
  • Genotype
  • Nomenclature
  • Also known as the Hooded rat
  • Used for neurological, toxicological and ophthalmologic studies
  • Reported higher resistance to respiratory problems than outbred albino rats, making the Long Evans rat the preferred stock for surgical procedures requiring extended use of inhalant anesthetics.


The Long Evans outbred model was developed by Dr. Long and Dr. Evans in 1915 by intercrossing Wistar Institute white female rats to wild grey male rats. Simonsen Laboratories received stock from the University of California Berkeley in 1949. The rats were derived by embryo transfer in 1975. The rats were derived by embryo transfer in August 1998 by Taconic.

Coat Color Loci:

a, h





n= 50 per sex at MPF health standard from US production colonies. Data collected 2012-15.
High and Low represent mean +/- 2 standard deviation.
Based on sample size the charts above represents ~75% of the population.
All growth curves represent animals housed in our barriers, at our standard density and fed NIH31-M diet. Variations at customer facilities will alter expected growth curves.
Growth charts are provided only as a guide, if a specific weight criteria is needed please order animals by weight.

Customize this chart by clicking the legend elements, then explore download options by hovering your cursor over the down arrow to the right of the chart title.
Average litter size: 11

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