Long Evans Outbred Rat Model
Available for immediate cryorecovery.

  • 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





For some applications, weight may be critical. For orders where weight is critical, please place orders by weight, not by age. Taconic can routinely accept orders by weight for this model for males only. Please inquire for female options if weight is critical for your experiment. A minimum 10 gram span is required. All weights are weights at time of packing. Mice and rats can lose weight in transit. Orders for specific weight spans will be assessed a nominal fee. More detail on weight order policies is available.

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