Sprague Dawley Rats
Rats are used in research because of the similarities in their behavioral patterns to those of humans. They are used in studies such as medicinal research and behavioral studies (Bioinfobank, 2008). The rats used in this study are Sprague Dawley rats. This breed of rat is albino and interbred to ensure the highest genetic similarity possible.
In general, the female Sprague Dawley rat weighs about 250-300 grams with a lifespan of 2.5-3.5 years. The natural life cycle for Sprague Dawley rats is short and therefore, reproduction occurs between the ages of 2-3 months. The first ovulation happens near 4-5 weeks of age. Gestation for Sprague Dawley on an average is a cycle of 22 days (Sprague Dawley, 2006).
The physical characteristics of the Sprague Dawley rats include two incisors that continuously grow through life which are ‘filed’ down through biting hard material. Sprague Dawleys are unable to vomit due to the esophagus entering the stomach. Interestingly, the left lung has one lobe while the right has four lobes. In females, the urethra is located separately from the vagina. Sprague Dawley rats also possess a harderian gland which is located behind the eyeball. Although it may appear to stain the areas around the eye with blood, it is simply a tear response to stressful stimuli and does not contain any blood (2006). With decrease in temperature, non-shivering thermo genesis occurs, which calls upon stored fat and transfers it into heat through the conversion of positive hydrogen ions (Dictionary, 2008). When there is an increase of heat, the rat’s tail tissues fill with blood in order to regulate body temperature (Sprague Dawley, 2006). Some symptoms one should be weary of are sneezing, hair loss or swelling of the body. Any of these symptoms could indicate a number of health concerns and one would want to see a veterinarian immediately. Breast tumors are common but can be decreased by spaying. Rats are susceptible to upper-respiratory infection, mange mites, infection in the salivary glands and ear infections. Therefore, rats must be kept in a clean environment to decrease the chances of becoming infected (Wood, 2008).
While rats are somewhat different biologically from humans, they display many similar behavioral traits to humans. This makes them ideal models to study behavior as well as medically, in order to infer results to humans.
References
Ace Animals, Incorporated. (2006). Sprague Dawley. Retrieved September 8, 2008, from http://aceanimals.com/SpragueDawley.htm.
Bio Info Bank. (2008). BioInfoBank Sprague Dawley. Retrieved September 10, 2008, from http://lib.bioinfo.pl/find?field=Papers&query=sprague+dawley.
The Free Dictionary By Fairlex. (2008). Medical Dictionary: Non-shivering thermogenesis. Retrieved September 8, 2008, from http://medical-dictionary.thefreedictionary.com/Non-shivering+thermogenesis.
Wood, Dr. Renee. (2008). Sprague Dawley Rats. Consultation over the phone Rosedale, Maryland: Veterinarian.
