Adapted from Susan Leck, DVM, Diplomat ABVP(canine and Feline Medicine)
Pet rats are of the species Rattus norvegicus. These nocturnal rodents are characterized by elongated bodies, short fur, small eyes and ears, and hairless tails. Common Strains/variations of pet rats include albino (white) rats, Dumbo rats, sphinx rats (hairless), silky rats, hooded rats, and many more. Rats can make great pets because they are easy to care for, have very little odour, and rarely bite. They are affectionate and intelligent animals that quickly bond to their owners.
Anatomically, rats have open inguinal canals, a diffuse pancreas, a divided stomach, a large caecum, and an os penis. Rats do not have gallbladders and cannot vomit. Albino rats have poor eyesight, and all rats depend on whiskers and scent for sensory input, sometimes weaving their heads back and forth to focus on objects. The red brown Harderian gland is a lachrymal gland located behind the eyeball; this gland produces a lipid and red porphyrin-rich secretion. In illness, red tears may overflow and stain the face and nose, and can also be spread or caked on wrists, ears and fur. There is no blood in this tear film and the red crusts will fluoresce bright under ultraviolet light. As rats age white hair coats can take on a yellowish cast.
Because rats are social and need companionship, they should be maintained in same sex or altered sex groups. Suitable bedding materials include shredded paper, recycled newspaper composite materials or pellets. Pine and cedar should not be used as litter because they are toxic to the animals. Bedding should be a minimum of one-quarter to one inch deep and changed at least 1 to 2 times per week. The housing should be escape-proof, wire mesh with plastic or metal solid flooring and should be large enough to allow nesting, burrowing, and exercise areas. Exercise may be provided in the form of a large exercise wheel and climbing toys. Minimal enclosure size guidelines for one adult rat are 24” X 24” X 12”high (with a secure wire-screen clamped top or other “roof” to prevent escaping).
Most rats will allow you to pick them up by placing the hand firmly over the back and rib cage, or by scooping them up in both hands. The head can be restrained with the thumb and forefinger behind the jaws. Scruffing the loose skin at the nape of the neck can help restrain and active rat, but many rats object to this.
Male rats have a scrotum, making them easily differentiated from female rats. The anogenital distance is roughly twice as long in males as in females. Rats are communal, and males and female may be combined in a solitary, uncrowded enclosure for breeding purposes. Young are raised communally with shared nursing responsibilities. If a female is not bred by 8 months of age, her pelvis will fuse and she may have difficulty giving birth later. Spaying may help prevent mammary tumours, which are relatively common. Pictured below is a male scrotum (very young).
Rats are omnivorous rodents. Many rat/rodent pellets are available commercially; these foods provide a complete diet. Sometimes small amounts of fresh fruits and vegetables are added. Adults require 5-10 gm of pellets per 100 gm of body weight daily and 10ml of water per 100 gm of body weight daily. Treats and seed-based diets are not recommended as they do not meet nutritional requirements. Fresh water should be available at all times, ideally provided via a drinking bottle or sipper tube. Rats may be suspicious of new foods that are introduced, so care must be taken to ensure the rat continues eating if a new brand of pelleted diet is offered.
Rats can have severe dental problems. Difficulty eating or dropping food may be signs that your rats teeth are misaligned. Infection or trauma can cause the incisors not to meet properly. Since these incisors continually grow, they will become quite long. We can help with this problem.