Rats are often kept by children as pets but increasingly they are also being kept by adults for breeding and showing purposes as well as for pets. Rats are easy to train and quickly become accustomed to being handled. I have known several pet rats that seemed to be extremely well bonded to their owners and they obviously gave much pleasure and companionship to their human keepers.
The species of rat usually kept as a pet is Rattus norvegicus and these animals come in a variety of colours. Self coloured rats are very common as are the hooded varieties which seem to be particularly friendly and easy to handle. A rat may live for 2 to 3 years so think carefully before you obtain one as a pet as it is a fairly long term commitment, especially for a child if it is to be their pet.
Rats may be housed in commercial or home-made cages. If you decide to make your own cage do remember that rats are good at chewing through plastic and wood and may escape from cages made from these materials. Good quality and interesting cages are readily available from most pet stores. It is usually a good idea to provide a separate sleeping compartment for your rat, although if there is plenty of bedding this may not be completely necessary. I strongly recommend that rats have adequate space in their cage to allow them to explore and play with toys. Toys for rats may include climbing apparatus, hollow tubes, balls, wheels and other objects which they can explore and investigate. Rats are intelligent animals and they need environmental enrichment with toys to prevent boredom and the exercise they do while investigating these objects will prevent obesity. Rats enjoy objects which they can chew or tear up; I often suggest untreated fruit wood such as a small branch of apple or pear for this purpose. Since rats are generally sociable animals it is a good idea to house two or three rats together in a large cage. It is easiest to keep animals in groups if they are introduced to each other as youngsters (adults may initially fight).
Bedding for rats is usually wood shavings, paper or sawdust. It is important to clean the cage at least once a week to avoid the spread of disease and also to prevent unpleasant smells. Rats are generally kept as indoor pets and will thrive in normal household conditions. Do not allow their environment to become too hot or too cold or the rats may suffer. It is always best to place the cage away from direct sunlight (if rats get too hot they may suffer from heatstroke) and draughts.
Rats are usually fed a commercial food and such products are easily obtained from pet stores. Many people supplement this diet with small treats. I would advocate the use of nutritious foods such as apples or vegetables for limited supplementation of the diet. Rats really enjoy biscuits, cake and chocolate but these should be reserved for special treats or used for training purposes otherwise the animals may become obese and unhealthy. Fresh, clean drinking water should always be available for your rat. I think that the sipper tube type dispensers are best for water since the water will not become contaminated with bedding, excreta or food.
Rats are usually quite friendly and amenable to being handled. They will not generally bite unless they are frightened or in pain. Rats should be picked up by gently grasping them around the body at the level of the shoulders; they do not like being picked up by the scruff of the neck. Take care that you do not hold so tightly that the rat cannot breath or the rat will panic and probably bite! Most rats will happily run along your arms and sit on your shoulders if allowed to do so. They often get lost in clothing so do take care not to hurt them as you try to get them out. It is possible to gently lift rats by the base of their tails but I prefer to lift them as described above.
Rats are easy to breed and unless you want a huge population of them you should generally keep them in single sex groups. (If you do want to keep a male and a female together but do not wish them to breed it is possible to have them neutered.) They become sexually mature and capable of breeding at around 9 weeks of age. Rats have no specific breeding season, they are polyoestrus and the oestrus cycle lasts 4 to 5 days. The duration of oestrus is 14 hours. If a female rat is mated a vaginal plug will form (a plug of ejaculate). This plug will shrink and fall out after about 12-24 hours. Pregnancy lasts about 21 days. The mammary glands develop during pregnancy and will become quite enlarged by day 16. It is possible to diagnose pregnancy in the rat during the later part of gestation by gently palpating the abdomen but this is probably best left to your vet. During the last few days of pregnancy the female rat will build a large nest from bedding material in which to give birth. Seperate the female from the male before the birth of her pups unless you want her to breed again, otherwise she will probably mate again within 12 hours. A female rat will on average give birth to a litter of 10 or so pups. You should not disturb her for at least 3 days after she has given birth or she may eat her pups. Rat pups are blind and hairless at birth but they grow very rapidly and are ready to be weaned at three weeks of age.
Rats really do make fantastic pets. Visit the rat section regularly to check for updates.