Lifespan: 2-4 years
Body weight: 300-400 g
Sexual maturity: 42-65 days
Gestation: 21-23 days
Liter size: 6-20
Newborns: body hair by 1 week of age and open eyes at 2 weeks
Weaning: 21-42 days
Daily diet consumption of adult (g): 15-20
Daily water consumption of adult (mL):22-33

Pet Potential/Behavior

  • Easy to care for.
  • Very little odor.
  • Affectionate and intelligent animals that bond quickly to their owners; rarely bite.
  • Albino rats tend to be the most calm and easily handled.
  • Hooded rats may be more aggressive and active.
  • Basically nocturnal, but can be active during the day.
  • Need at least 30 minutes each day for exercise.
  • Chew on objects to maintain incisor teeth, which grow continuously. It is important to have plenty of chew sticks available.
  • Dogs, cats, and ferrets are rats’ predators.
  • Often difficult to litter-train (fecal).

Anatomy and Physiology

  • Rats are characterized by elongated bodies, short fur, small eyes and ears and hairless tails.
  • Rats do not have gallbladders.
  • Rats do not vomit due to the presence of a limiting ridge at the junction of the esophagus and stomach.
  • Females have extensive mammary tissue.
  • Because rats have poor eyesight, they rely on whiskers and scent for sensory input and spatial orientation.
  • Rats teeth turn yellow as they age (albino fur as well).
  • Rats have harderian glands which are located behind the eye. These cause “red tears” from stress or illness.

Sexing and Reproduction

  • Male rats have a scrotum,making them easily differentiated from female rats.
  • The distance between the anus and genital area is roughly twice as long in males as in females.
  • Only female rats possess nipples.
  • Rats are communal, and males and females may be combined in an uncrowded enclosure for breeding.
  • 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 to prevent mammary tumors, which are common in middle-aged to older rats.


  • Housingshould be constructed of escape-proof wire mesh with plastic or metal solid flooring and should be large enough to allow nesting, burrowing and exercise.
  • Rats love to climb so a tall habitat is recommended; it will allow challenges for your rat.
  • Minimal enclosure size guidelines for one adult rat are 24” x 24” x 12” (61 x 61 x 30 cm).
  • A secure wire screen clamped top or other roof is necessary to prevent escape.
  • Ideal room temperature should be 5-80 degrees F (18-26 degrees C).
  • Ideal humidity should be 40-70%.
  • Because rats are social and need companionship, they should be maintained in same sex or altered sex groups.
  • Suitable substrates include shredded paper (non-inked), recycled newspaper composite materials or pellets, hardwood chips or shavings and compressed wheat straw.
  • Cedar should not be used as litter because it is detrimental to the rat’s health by causing microsomal oxidative liver enzymes.
  • Bedding should be a minimum of ¼ inch to 1 inch deep and changed at least 1-2 times per week.
  • Housing should be cleaned weekly to minimize respiratory disease risk.  Remove wet spots daily.
  • Exercise may be provided in the form of a large exercise wheel and climbing toys.
  • Toys, such as tubes (paper towel rolls), provide the rat with environmental enrichment and exercise.


  • Rats are omnivorous (eat both animal and plant derivatives) rodents.
  • Rat/rodents pellets provide a complete diet. Recommended brands include Mazuri, ZuPreem and Oxbow Pet Products.
  • Small amounts of fresh fruits and vegetables may be added.
  • Seed-based diets are not recommended as they do not meet nutritional requirements and predispose to obesity.
  • Adults require 5-10 g of pellets per 100 g body weight daily and 10 ml of water per 100 g body weight daily.
  • Fresh water should be available at all times, ideally provided via a drinking bottle or sipper tube.
  • Food consumption should be monitored when new food is offered because rats may be suspicious of new food.
  • Discard food if not eaten within 24 hours.

Grooming and Hygiene

  • Rats stay clean and rarely need baths.
  • Consult with a veterinarian if your rat’s teeth or nails seem too long.
  • Because all rats are potential carriers of infectious diseases, such as Rat Bite Fever, always wash your hands before and after handling your rat and/or habitat contents to help prevent the potential spread of diseases.
  • Pregnant women and people with weakened immune systems should contact their physician before purchasing and/or caring for a rat.

Extra Tip

  • May be helpful to purchase a gram scale to keep track of your rat’s weight and food consumption.

This information is provided through Valley Veterinary Hospital and the following sources. If you have any further questions regarding rat “husbandry and health, please contact our hospital at701-232-3391.

“The Exotic Guidebook Exotic Companion Animal Procedures,” written by Susan LeckDVM Dipl ABVP – Canine & Feline Practice Edited by Peter Fisher, DVM.

Petco Animal Care Sheets, Rat;