RAT (Rattus norvegicus)
Natural The Norwegian or brown history rat is originally from Asia where it lived in burrows on the plains of northern China and Mongolia. The rat arrived in Europe in the early 18th century and had reached America by the late 18th century. The brown rat was the first species to be domesticated for scientific purposes.
Taxonomy Class Mammalia Order Rodentia Suborder Myomorpha Family Muridae (rats, mice) Muridae is the largest and most diverse family of mammals.
Breeds A variety of breeds, colors, and markings are recognized.
Diet Rats are omnivores. The bulk of the diet should consist of a rodent block or pellet containing a minimum 16% crude protein and 4-5% fat. Seed-based diets promote obesity and should be avoided. Longevity is increased by feeding a low fat, vegetable protein-based diet.
Husbandry Rats are social creatures, although females are more likely to fight. Rats are primarily nocturnal, but they will have cycles of activity during the day and night. Avoid bright lighting in albino rats. Adult brown rats tolerate cold well when allowed to acclimate. Provide rats with items and materials for burrowing, climbing, and chewing.
Normal Temperature 99.9°F 37.7°C physiologic Pulse 300-500 bpm values Respiration 70-150 bpm Adult male 267-500 g Adult female 225-325 g Mean life span 2.5-3.5y Female rats typically live longer. Sexual maturity 37-75 days Puberty occurs earlier in female rats. Target environmental temperature: 50-68°F 18-26°C Target relative humidity: 40-70% RAT Gestation 21-23 days Normal Litter size 6 to 13 physiologic Birth weight 5-6 g values Weaning 21 days Water intake 22-33 ml/day
The harderian gland lies behind the eye and fills a large part of the orbit. The Anatomy/ harderian gland secretes lipids and a red porphyrin pigment Physiology which fluoresces under UV light. Secretion increases with stress or disease
Rats have a well-developed sense of hearing, touch, and smell, but poor vision. Eyesight is especially poor in albinos. Rats can hear high frequency sounds so take care with high pitched and ultrasound noises emitted from equipment like TVs and computers.
Dental formula Incisor 1/1 canine 0/0 premolar 0/0 molar 3/3 Iron pigments create the yellow-orange color of the incisors. The lower incisors are normally 3X longer than the upper incisors. Incisors are open-rooted but molars stop by growing by Day 125.
All rodents are obligate nasal breathers.
Testicles are evident by 3-4 weeks. In addition to 6 mammary glands on each side of midline, mammary tissue extends from the neck to elbow and down into the inguinal region.
Restraint Rats are generally docile and are easy to handle. For manual restraint, grasp the rat over the back and place a thumb in the axilla pushing a foreleg up towards the chin.
Venipuncture Collect blood samples from the lateral tail vein, ventral tail artery, femoral vein, jugular vein, or lateral saphenous vein. Warm the tail first to promote vasodilation.
Important medical Mammary tumors conditions Mycoplasmosis
References Banks RE, Sharp JM, Doss SD, Vanderford DA. Exotic Small Mammal Care and and further Husbandry. Durham, NC: Wiley-Blackwell; 2010. reading Dyer SM, Cervasio EL. An overview of restraint and blood collection techniques in exotic pet practice. Vet Clin Exot Anim 11:423-443, 2008. Mitchell MA, Tully TN. Manual of Exotic Pet Practice. St. Louis, MO: Saunders Elsevier; 2009. Quesenberry KE, Carpenter JW (eds). Ferrets, Rabbits, and Rodents: Clinical Medicine and Surgery, 2nd ed. Philadelphia, WB Saunders, 2003. O’Malley B (ed). Clinical Anatomy and Physiology of Exotic Species. Saunders Elsevier. 2005. Pp. 209-225. Sirois M. Laboratory Animal Medicine: Principles and Procedures. Mosby; 2004.
Author: Christal Pollock, DVM, Dipl. ABVP-Avian; Lafeber Company veterinary consultant Date: February 14, 2010