Category: mice and rats

Mice and rats: routine health care

Posted on June 25, 2018 by vetstream - mice and rats, rodents

We are all familiar with the phrase “A healthy pet is a happy pet” – but there is probably also something to be said for keeping your rodent happy in order to maintain its health. If you know your pet you will probably quickly recognise the signs that suggest it is not well.

What are the signs of good health?

A healthy rodent will have bright eyes, clean ears, eyes and nose and be interested in what is going on around it.

If your rodent’s weight remains constant then they are eating the right amount of food. You should be concerned if their appetite or water consumption suddenly changes or they suddenly start to gain or lose weight. When in good condition the coat should be shiny, soft and free of parasites.

How do I keep my rodent in good health?

Your rodent must be fed a healthy diet and allowed regular exercise.

The closer your rodent’s diet and environment is compared to how it would eat and live in the wild, the healthier and happier it will be. Giving them plenty of enrichment in also hugely important for their mental wellbeing.

What is a healthy diet?

A healthy diet is a balanced diet containing all the nutrients your pet requires.

Mice and rats are omnivores, which means that, like us, they naturally eat mainly vegetable matter, but to keep in good health require some food of animal origin as well, e.g. cheese, insects, meat, egg, etc.

How can I maintain my rodent's health?

There are a number of measures that can help prevent your pet developing diseases. You should discuss the special needs of your pet with your vet.

Vaccinations

Mice and rats do not require vaccinations.

Dental care

All rodents have front teeth that grow continuously, so a high fibre diet is essential to allow the teeth to wear down naturally. You could provide something for your pet to gnaw on, for example a wood or hide chew toy. This will help to keep your pet’s teeth in good condition and prevent dental problems.

If you notice any signs of overlong teeth then your vet will be able to burr the teeth down and advise you further.

How do I know if my rodent is unwell?

If your rodent has a poor coat condition, dull eyes, dirty ears, eyes or nose it may indicate that they are unwell. Changes in behaviour (a normally happy and affectionate animal may become grumpy and avoid human contact, preferring to hide away by itself), altered appetite or water consumption should also alert you to the possibility that there may be a problem.

Most animals recover from illness in 24-48 hours – if your pet does not seem to be improving in this time or is getting worse then you should contact your vet.

Mice and rats: parasitic diseases

Posted on June 25, 2018 by vetstream - mice and rats, rodents

Rodents are susceptible to skin disease which can be caused by numerous infectious agents, including bacteria, viruses, fungi and parasites. Cage mates may be responsible for hair loss and/or wounds to the skin.

Do rodents suffer from external parasites?

Pet mice and rats may be infested with a variety of external parasites. Mites, nearly microscopic, spider-like organisms, live on the skin surface and feed primarily on skin debris. They are transmitted by direct contact between infested and uninfested rodents. Signs of infestation range from mild scratching to severe scratching, with hair loss and ulceration of the skin.

Your vet should be consulted if mite infestation is suspected. Microscopic examination of a scraping of the skin is necessary to confirm the diagnosis. Treatment may include an injectable drug that has proven very effective in treating mange in a wide range of animals.

Lice may also infest the haircoats of pet mice and rats. They are flattened, wingless insects that suck tissue fluids and blood from the skin of the host. Lice are larger than mites and can usually be seen without a magnifying lens. Lice are most often transmitted by direct contact with infested bedding and between infested and uninfested individuals. Lice are usually found on the neck and body. They suck blood and can, therefore, cause anaemia (sometimes death) and transmit blood borne diseases to rodents. Louse infestations may also cause scratching, hair loss and skin wounds. You should consult your vet if you think your pet might have a louse infestation.

Allergies are also a suspected cause of skin disease of pet rodents. In these cases, it is wise to replace the bedding being used with plain white, unscented paper towelling. You should consult your vet if you think your pet is exhibiting signs of skin disease. Your vet will need to conduct some diagnostic tests to find out what is the cause; they will then prescribe appropriate treatment based on the results of these tests.

Do rodents suffer from intestinal parasites?

Tapeworms and pinworms are the most common intestinal parasites of pet mice and rats. They often go undetected unless present in large numbers. Signs of infection may include weight loss, inactivity, inappetence, constipation, and excessive licking and chewing of the rectal area and base of the tail.

Your vet can perform a stool examination to diagnose these parasites, and they will be able to recommend appropriate treatment. Pinworms are especially difficult (sometimes impossible) to eliminate from mice and rats. Transmission of these parasites to people is also possible but unlikely. Therefore, great care should be taken when handling and disposing of rodent faeces. Furthermore, contact between pet mice and rats, their faeces, and young children should be limited and always supervised by adults.

Mice and rats: miscellaneous health problems

Posted on June 25, 2018 by vetstream - mice and rats, rodents

Two medical conditions of mice and rats demanding special mention are their susceptibility to tumours and Tyzzer’s disease. These are covered in separate factsheets. However, there are other medical conditions affecting mice and rats that are briefly covered here. Only purchase rodents from reputable sources, and never purchase an obviously or even suspiciously ill rodent. It is never wise to purchase an animal that has been in contact with one that seems ill, even if the intended purchase appears perfectly healthy. Strict quarantine or isolation of all newly acquired rodents for at least 4 weeks greatly helps prevent disease among pet mice and rats. This recommendation is especially important for pet rodents because of the severity of certain diseases that they may harbor without showing signs of illness.

What should I do if I think my pet is overweight?

The tendency to become overweight (often grossly overweight) is more often a problem of pet rats than mice. Overindulgent pet owners and the provision of diets rich in seeds and nuts are most often responsible for this condition.

Owners of pet rats must resist the temptation to feed “junk food,” such as French fries, doughnuts, cookies and candy. Commercial diets specifically designed for rats are always preferred and can be supplemented with whole-wheat bread, dry cereal, pasta, fruits, vegetables and non-fat yogurt.

I think my pet has overgrown teeth - help!

The incisor (front, gnawing) teeth of all rodents and rabbits grow continuously for the life of the individual. The continual wear between the uppers and lowers usually prevents overgrowth of the teeth. Hereditary abnormalities of the jaw bones and/or teeth, abscessation of the incisor teeth, or injury to he jaw may result in malocclusion (improper meeting of the upper and lower incisors).

Malocclusion, in turn, results in overgrowth of one or more of the incisors, with subsequent injury to the mouth. Mice and rats with this problem must have their overgrown incisors trimmed periodically by an experienced vet or vet technician.

Why does my rat have red tears?

Rat owners, at some point, notice red-brown tears staining the eyelids, nose and sometimes the front paws of their pet rats. This substance is always mistaken for blood, but don’t panic, it isn’t!

It is actually a normal secretion from a large gland behind the eyes. Red-brown tears are noted most often in response to stressful situations such as restraint, fright, illness, etc.

Do rodents eat each other?

Female rats (mice much less often) disturbed shortly after giving birth to a litter may destroy the pups and eat them. Male rats also engage in the same behaviour. For these reasons, it is important not to disturb female rodents for 2-3 days after they have given birth. Male rats must be removed from enclosures just before the females are due to deliver their litters to prevent this from happening.

Mice and rats: how to handle

Posted on June 25, 2018 by vetstream - mice and rats, rodents

Domestic mice and rats generally tolerate gentle handling, though both may bite if startled or handled roughly. Mice are more likely to bite than rats under these circumstances. In fact, mice housed alone are more likely to be aggressive with a handler than those housed in groups.

How should I handle my mice?

It is customary to pick up a pet mouse by gently lifting it up by the tail and placing it into a cupped hand.

If a more secure hold is necessary (giving medications or food orally), the handler may grasp or pinch as much skin as possible over the neck, just behind the head, the mouse can then be picked up and turned over on its back by rotating the wrist. The tail can also be restrained by gently grasping it with the other hand, or between the fourth (ring) and fifth (pinkie) fingers of the same hand.

How should I handle my rats?

Rats can be lifted by their tails but great caution must be exercised in doing so.

The skin of a rat’s tail can easily tear, so it is best to grasp only the base of the tail. Furthermore, suspending the entire weight a rat by its tail is, no doubt, painful for the rat. Therefore, this practice should be only momentary.

Tall-lifting a rat that is grasping a fabric (wire mesh, etc) may injure the tail and may also break or tear the toe nails.

The best way to pick up a rat is to place one hand over the back, just behind the head, gently grasp it around the rib cage, and lift it upward. The rat can then be gently cradled against the handler’s body, using minimal restraint.

How should I handle aggressive mice or rats?

Potentially aggressive or known vicious rats and mice can be captured and restrained using gloves and small towels to protect the hands of the handler.

Cage-aggressive rodents should be allowed to come out of their enclosure before an attempt is made to pick them up.

Mice and rats: housing

Posted on June 25, 2018 by vetstream - mice and rats, rodents

Proper housing is a major factor in the maintenance of healthy mice and rats. The psychosocial well-being of the animals must be a primary consideration. Mice and rats can be housed within enclosures made of wire, stainless steel, durable plastic or glass.

What sort of housing should I provide my pets?

Stainless steel, durable plastic or glass are preferred materials for a rodent enclosure because they resist corrosion. Wood and similar materials should not be used in the construction of enclosures because they are difficult to clean and cannot withstand the destructive gnawing of rodents.

The construction and design of the enclosure must ensure that the residents cannot escape! Furthermore, the enclosure must be free of sharp edges and other potential hazards. The enclosure must be roomy enough to allow the rodents to pursue normal movement and breeding activity, if the latter is desired. Visual security, i.e. a place into or under which the rodents can retreat for privacy, should be provided, as well as exercise wheels for optimum mental and physical health. Rats, in particular, tend to be burrowers and seem to enjoy hiding under things for extended periods.

Enclosures should be easy to clean, well lit and adequately ventilated. Bedding must be clean, non-toxic, absorbent, relatively dust-free and easy to replace. Shredded paper, hardwood shavings and processed corn cobs are preferred bedding materials. Tissue paper or cotton are often supplied to breeding rats for nest-building material.

Cedar shavings should be avoided as the aromatic oils in the cedar are toxic to animals. Pet mice and rats seem most comfortable when they are spared exposure to excessive noise, needless excitement and confusion, and other similar or perceived stresses. Sudden environmental temperature changes should also be prevented because pet rodents do not tolerate them well.

How often should I clean the enclosure?

The frequency with which the enclosure should be cleaned depends on its design, the materials out of which it is made, and the number of rodents within. As a general rule of thumb, however, the enclosure and all cage “furniture” should be cleaned and disinfected once weekly.

The food and water containers should be cleaned and disinfected once a day. More than one set of containers should be maintained, and the soiled set should be washed in a dishwasher, if possible. Vigorous scrubbing of the enclosure and “furniture” with hot water and soap and a thorough rinse should be followed by the use of a disinfectant. Vinegar is often required to remove the scale deposited by rodent urine.

Rats and mice are especially sensitive to the irritating effects of ammonia. This chemical builds up quickly in the bedding from the relatively large volume of urine excreted by pet mice and rats. Bedding must be changed 2-3 times each week, or more often if necessary. Furthermore, ventilation must be adequate to reduce or eliminate the irritating effects of ammonia on the respiratory lining of pet rodents.

Mice and rats: feeding a healthy diet

Posted on June 25, 2018 by vetstream - mice and rats, rodents

The mice we keep as pets are the same species as the house mouse. They live alongside human beings nearly all over the world, eating what they can find. Rats are designed to eat plants, e.g. seeds, roots, nuts and fruit. The cheek teeth of the rat are more like our own than the teeth of rabbits or guinea pigs. They don’t keep growing throughout the animal’s life, but like ours, they erupt when the animal is young and have to last it all its life. The incisors are constantly growing and wearing against each other to form the characteristic chisel shape. Rats like to gnaw to keep their teeth in trim and because their natural diet would demand it; do not chop or grate vegetables too finely but let them gnaw pieces off themselves.

Feeding mice

Mice are ‘omnivores’, which means that, like us, they have evolved to eat mainly vegetable matter, but to keep in good health require some food of animal origin as well. The best commercial small mammal mix to feed your mice would be one that is sold in sealed packets, so it remains fresh, and that contains some protein of animal origin (look at the label on the back of the packet for this information).

Fresh food

Mice will eat fresh food too; they will eat almost anything, but to keep them in the best of health feed a selection of bits of fruit and vegetables each day – try different ones to see what their favourites are. You can also feed things like dried fruits, pieces of toast, pasta and rice. Some mice like sweet things like fruit yoghurts, but these should be small amounts and only occasionally to prevent obesity.

Cheese and meat

Mice are famous for being mad about cheese, although people who don’t like mice find that they catch more if they bait a trap with bread instead! However, you can certainly try your mice with cheese and meat. Another good source of protein is eggs.

Foods to avoid

To keep your mice in good health, you should avoid feeding too much food containing lots of sugar, for example sweet biscuits or chocolate. You should also avoid feeding anything that is high in fat.

Feeding rats

Rats are ‘omnivores’, which means that, like us, they have evolved to eat mainly vegetable matter, but to keep in good health require some food of animal origin as well. There are some very good rat mixes on the market. You should always supplement your rat’s diet with a good selection of fresh food including fruits and vegetables, pieces of hard-boiled egg, cheese, they will even eat the dregs from your yoghurt pot!

Commercial mixes

Firstly look at the label; the protein level should be in the mid- to high-teens (15-18%), and some of that should be animal protein. Mixes that are predominately seeds and peanuts will make the rat fat but unhealthy. Make sure the pack is within its sell-by date. Secondly look at the mix; it should smell fresh and not be dusty. It is better to buy a packaged mix rather than a loose mix from a large bin – this will ensure freshness.

A good commercial mix has been well thought out and provides all the nutrients the rat needs for a long and healthy life. Many pet rats are fed on the same food as their owners, and seem to be remarkably healthy. Some people even alter their shopping habits to keep their rats on a healthy diet! A rat that starts the day with a bowl of cereal, some toast and a bit of fruit, and has bread, fruit and vegetables to nibble during the day, and shares your supper at night could live a long and healthy rat life!

Pellets

Some owners feed their rats the sort of pellets fed to laboratory rats. They need to be fit and well, and the pellets they are fed provide a balanced diet.

Treats

If you know a treat would be good for you, it will also be good for your rat. So, if you eat a healthy diet, anything you consider to be healthy for you will be healthy for your rat. Try to avoid food that is very sweet, fatty or salty. However, it is very easy to produce a fat rat as they are so much smaller than us – one peanut provides a great proportion of their calories for the day. Seeds and nuts should therefore be kept to a minimum of 1 or 2 peanuts and sunflower seeds per day.

Can poor diet lead to disease in rats?

Obesity in pet rats is a known problem. Plenty of exercise with limited access top chocolate biscuits and high fat seeds will prevent this problem. Wild rats have evolved to be survivors, and can survive even on a poor diet, but there is no doubt that a good and varied diet makes for a healthy pet rat, with increased resistance to disease.

Mice and rats: a history

Posted on June 25, 2018 by vetstream - mice and rats, rodents

Domestically raised mice and rats are popular pets these days; they are readily available, relatively inexpensive and easy to care for, and usually enjoy human handling.

All about mice and rats

These animals have been used extensively in research laboratories for many years. Consequently, their medical problems (many of which are inherited disorders resulting from intensive inbreeding) have been traditionally approached on a group basis rather than on an individual basis.

As a result, very little practical and useful information exists on the medical care and treatment of individual pet mice and rats. Furthermore, even less information is available to the pet owner on responsible home care of murine rodents and recognition of their potential medical problems.

Mice

The mouse, bearing the scientific name Mus musculus – interestingly, the Great Blue Whale’s scientific name is Balenoptera musculus – is thought to have originated in Asia. Its tremendous adaptability, long-time association with people and our dwellings, and unbelievably prolific breeding potential (one reference cites one million descendants from one breeding pair in 1 1/2 years) has allowed mice to enjoy a worldwide distribution.

Mice are timid, social and territorial animals that spend a disproportionate amount of time in the wild pursuing an omnivorous (animal and plant material) diet. Feeding is most often carried out at night to escape predation. Laboratory and pet mice are not strictly nocturnal (night-active) but tend to exhibit alternating periods of activity and rest throughout the day and night.

In the wild, mice may exhibit aggression among themselves, though establishment of a social “pecking order” tends to reduce this potentially injurious behaviour. Individual males apparently dominate groups of mice using this social pecking order, and females with litters may fight to defend their nests.

Domestication and intensive breeding of mice have resulted in a tremendous genetic diversity of mouse populations. The Swiss Albino mouse has become one of the most popular strains for pets but many others are commonly seen.

Scientific name: Mus musculus
Life Span: 2-3 years
Potential Life Span: 4 years
Desirable environmental temperature range: 18-27°C/65-80°F (20-22°C/68-72°F optimum)
Desirable relative humidity range: 30-70%
Age at onset of puberty: 28-40 days
Estrous (heat) cycle length: 4-5 days
Estrous length (period during which female is receptive to male for copulation): 12 hours
Gestation (pregnancy) period: 19-21 days
Average litter size: 10-12 (1st litter usually smaller)
Weaning age: 21-28 days

Rats

The rat, bearing the scientific name Rattus norvegicus, apparently also originated in central Asia. Rats were domesticated in the 17th century and the process has continued to the present, resulting in many breeds that are docile which makes them great pets.

Rats, like mice, have been used extensively in biomedical research. Most of the tremendous number of breeds and strains currently in existence have resulted from intensive inbreeding efforts by research laboratories over the years.

Wild rats are found in all kinds of habitats and nearly all land masses of the world, an enduring tribute to their adaptability and their long-time association with people.

They tend to be omnivorous (feed on plant and animal material) but exhibit tremendous opportunism in their feeding habits when living in and around human dwellings.

Wild rats tend to be nocturnal (night-active) animals but often use daylight hours to forage for food. Laboratory rats, like laboratory mice, on the other hand, are not strictly nocturnal. Mice and rats are both relatively short-lived animals, which can be disconcerting to owners of these pets.

Some, however, feel that having their children experience the relatively short period of companionship and subsequent death of pet mice and rats is a meaningful way to expose children to the “ups and downs” of life.