Caring for your pet rat
Pet Rats (Rattus Norvegicus)
Many people are frightened of rats but pet rats are very intelligent and sociable animals. They form strong attachments to people but are best kept with another rat for company. As pet rats were originally bred from laboratory stock they do not carry any nasty diseases and make safe and fun pets. The only downside to having a pet rat is that sadly they are not long-lived with a lifespan of on average 2 – 3 years.
Rats are omnivores meaning they can eat anything. Ideally they should be fed rodent pellets (e.g. Excel Supa rat or verselaga pellets) with some fresh healthy food. A vegetarian diet has been proven to increase longevity so feed plenty of vegetables. Many rats suffer from obesity so avoid high calorie rodent seed, muesli and nut mixes and anything like chocolate, crisps or pizza.
Rats are very social so if possible keep them in pairs or small social groups. Males must be neutered at 5-6 months to prevent fighting. Females tend to adapt to newcomers better and can be mixed with neutered males. A large wire cage with lots of floor levels are best as rats love to climb and explore. The floor should be solid with a floor litter of recycled paper pellets ( eg carefresh). Avoid wood shavings or sawdust as they can cause respiratory disease. Provide lots of hidey holes made from flower pots, cardboard boxes and PVC pipes. Rats love to make a nest so provide old clothing or paper towel for them to shred up. Aquarium style tanks are not recommended for rats as ammonia can build up and make them susceptible to respiratory disease. Rats are often let roam free range but must be watched at all times to avoid them chewing electric cables, wallpaper or your curtains!
Common Medical problems
Pneumonia and chronic respiratory disease are the most common cause of illness and death in pet rats. Respiratory disease can also lie dormant and break out when the rat is under some stress like after anaesthesia, bullying from a cage mate or a new owner.
Respiratory disease in the rat is caused by a mixture of bacteria (mycoplasma pulmonis, streptococcus pneumonia, corynebacterium kutscheri) and lots of different viruses (sendai virus, CAR bacillus, sialodacryoadenitis virus). Rats usually get respiratory disease from the mother in the womb or while suckling. It can also be spread from other rats by aerosol droplets via sneezing.
What are the signs of respiratory disease?
The symptoms will vary according to the severity of the infection. Signs include lethargy, hiding away, lack of appetite, laboured breathing and hunched posture. The coat will become unkempt due to lack of grooming and there may be weight loss and / or red tears*. In some cases, bacteria ascend the eustachian tube into the middle ear causing a head tilt and lack of balance.
Red tears and nasal discharge are caused by porphyrin pigments coming from small gland inside the third eyelid called the Harderian gland. Owners often confuse this with an eye infection or a nosebleed. When seen it is an indicator of some form of stress most often linked to underlying viral respiratory disease. The scientific names for this is chromodacryrrhoea which literally means the coloured flow of tears. Signs usually resolve after 1-2 weeks.
How do I prevent my rat from getting respiratory disease?
- · Mycoplasma bacteria multiplies in the presence of ammonia (urine) so good cage hygiene is vital. The cage should be cleaned out and disinfected at least once a week and the floor litter changed completely to stop ammonia building up
- Use well ventilated cages with either paper towel or recycled cardboard (eg carefresh) for bedding to avoid allergies and dust. Do not use aquarium style tanks.
- Source your pet from a known mother with no history of respiratory disease.
Firstly, good cage hygiene is vital – many a rat owner spends hours trawling the rat forums in quest of the perfect antibiotic ignoring the fact that they have a cage smelling of rat urine! Antibiotics will help alleviate clinical signs if the cause is bacterial (eg mycoplasma) but does not eliminate the disease if viruses are also involved. Rat with wheezy chests and noisy breathing may also need treatment with anti-inflammatories and bronchodilators. Rats with pneumonia often get dehydrated and will need to be hospitalised for fluid therapy, nebulising, inhaler therapy and even oxygen. They expend so much energy trying to breathe that they lose weight rapidly so should be coaxed to eat with fruit baby food, yoghurt, custard or any tasty treats.
Mammary or breast cancer
Rats have 6 pairs of mammary gland and mammary tissue is so extensive it lies from above the armpit along the flanks to the groin. Hence mammary tumours are frequently mistaken for skin tumours. It is more common in females but males an also be affected. The good new is that 90% of mammary tumours of the rats are benign fibroadenomas. The bad news is that the tumours grow alarmingly fast and if left untreated can reach 40% of total body weight! Surgical removal is usually successful but new ones can grow on any of the other 11 mammary glands.
How do I prevent breast cancer?
Males and females need to be neutered as young as practical – about 5-6 months
Ageing male rats develop pronounced yellow flecks of dry skin along the back and tail which if often confused with skin parasites. Shampooing with anti-seborrhoea shampoos will help make the pet more cosmetically acceptable. Castration of young males prevents this problem.
The rat will show thinning of hair on head and trunk. The mites are spread by direct contact with affected animals or bedding. Baby rats acquire mite before weaning from their parents but don't show signs until maturity. Many rats with mites will scratch and develop little hypersensitivity sores on their skin. Treatment is by an injection or topical spot on (xeno drops) containing ivermection every two weeks for 2-3 times. All rats in the same cage must be treated and the cage emptied of all floor litter and cleaned out well.
This is a tumour of the master hormonal gland at the base of the brain. The most common is a benign tumour called a prolactinoma that can either be a micro or macroadenomas. These tumours are slow growing but as they get bigger they cause pressure on the brain causing neurological problems. They are a common cause of ill health and death in older rats but can be seen as early as 1 year. They are more common in females. As most pituitary tumours are hormone sensitive early neutering at 5-6 months helps reduce the incidence. High calories / and protein diets also contribute to their formation The signs and response to treatment will depend on what type of tumour is present. Macroadenomas will cause more rapid deterioration of signs as they are bigger, occupy more space and will press more on vital areas of 5the brain.
The rat will show progressive neurological signs like dullness (headache), head tilt, blindness, circling and incoordination and even seizures. Some rats head press and show aggressive behavioural changes. Many rats lose the power of their front legs - they become unable to hold food in their hands and struggle to climb the bars of their cage. Terminally ill rats often show breathing difficulties due to pressure of the tumour on the respiratory centre of the brain .Hormonal signs can be increased drinking and urinating, thinning of the skin and even lactation from the mammary glands.
Medical treatment is with steroids (prednisolone) to decrease tumour swelling pressing on the brain. As most pituitary tumours secrete the hormone prolactin these tumours respond well to a dopamine inhibitor drug called cabergoline. Dopamine is a chemical in the brain which inhibits the production of prolactin. Rats with pituitary tumours can be debilitated and need careful nursing. Provide soft fleece bedding, help them eat by syringe feeding and convert their cage into a bungalow so they don't need to climb. Euthanasia however will be necessary when quality of life becomes poor.