Rats and Mice
Rats and mice are both popular as children’s pets. They soon become accustomed to handling and are easy to train. They are cheap to purchase and easy to maintain. Mice are happiest in pairs or small groups. They are not particularly responsive to attention and often escape. Rats are quite happy to be alone and will readily respond to attention.
Female mice smell less than males, and don’t tend to fight as much so may be preferable as pets. They live for 2-3 years, but commonly acquire tumours which are often fatal.
Rats live for 3-4 years, but commonly suffer from obesity and chronic respiratory disease which shortens their life.
Neither rats or mice have a specific breeding season. Both build nests a few days before giving birth, and the new mothers should not be handled for a few days or they may eat their own young. This is particularly the case with rats.
Mice are sexually mature at 6-7 weeks, on heat for 4-5 days and pregnant for 19-21 days. They usually have between 8-12 young and weaning is at 3-4 weeks.
Rats are sexually mature at 8-10 weeks, on heat for 4-5 days and pregnant for 20-22 days. Litters range from 6-16 with weaning at 3-4 weeks. The young are known as pups and are born blind and hairless.
Commercially produced complete rations are the most convenient diet for rats and mice and can be supplemented with biscuits, apples, tomatoes and dog biscuits. Rats are fond of chocolate and cake and small amounts of these can be used to train them. Rats and mice tolerate diet changes easily, but both are prone to over eating and obesity
The diet should contain at least 16% protein and 4-5 % fat. Some people feed selected bird seeds, but some, such as sunflower are high in fat and low in calcium and can lead to obesity and brittle bones. Water must be available at all times.
Metal or glass cages are necessary as small rodents readily chew through wood and plastic. The cages must be kept clean and have room to exercise. Wheels, ladders, tubes and climbing frames will all provide exercise and prevent boredom whilst making an entertaining pet. Bedding can be of paper, soft wood shavings, sawdust, and tissue paper.
Bedding should be changed 2-3 times each week to minimise odour and risk of disease. Rats and mice should be housed indoors at a temperature between 15-27 degrees Celsius. Temperatures over 30 degrees may cause heat stroke.
Preventative Care and Diseases
Try to bring your rat or mouse to the vet in a small container rather than the main cage to allow easier capture and restraint and so less stress.
Pets bought from private sources and kept isolated are less likely to suffer from infectious diseases than ones bought from a pet shop.
Animals presenting severely depressed or with respiratory signs have a poor prognosis for recovery. Rodents do not require vaccination.
Occasionally they may suffer from pin worm and mite infestations which are treated with Ivermectin.
It is possible to desex male rats, but there is an anaesthetic risk and the surgery is more delicate than that for dogs and cats.
Dental problems are frequent as the front incisor teeth are continuously growing for the animal’s life, and may overgrow and need to be filed.
Skin diseases are common. Barbering is seen in group– housed mice due to the dominant mouse chewing the whiskers and hair off the muzzle of cage mates. Only one mouse retains all of its fur. Removal of this mouse from the group will cure this problem. Self trauma is another frequent cause of dermatitis which can be distinguished from barbering by presence of skin lesions. Boredom, or mite or fungal infections may be the originating cause of the trauma.
Viral diarrhoea or bacterial diarrhoea may affect young, usually causing death.
Respiratory diseases are very common in pet mice and rats. Many animals have extensive lesions in the lungs but may not show clinical signs for some time. Clinical signs are sneezing, snuffling, chattering, difficulty breathing and weight loss. Antibiotics may help but don’t eliminate disease which is recurrent.
Older rats frequently suffer from kidney disease which is secondary to chronic respiratory disease.