Chinchillas (Chinchilla lanigera) are small rodents that originate from mountainous regions in South America. They live in large social groups at between 3000 and 5000 metres, living in burrows or rock crevices. They are adapted to survive the low temperatures encountered at these altitudes and have very soft dense fur. This soft fur was highly prized and hunting hugely reduced wild chinchilla numbers and they are now listed as an endangered species. The chinchilla has since been farmed for fur production. Increasing numbers of chinchillas are being kept as pets in the UK (Figure 1) and are increasingly encountered in the veterinary practice. Wild chinchillas are a yellow grey colour; however selective breeding has resulted in the commonly seen blue grey colour. There are now a variety of colours available including beige, white, sapphire, charcoal, ebony and violet. Domestic chinchillas are larger than wild chinchillas. This article outlines the husbandry and care of chinchillas; many chinchillas presented for veterinary treatment have conditions that result from incorrect diet and husbandry.
Appearance
Chinchillas have soft dense fur with 60–90 hairs emerging from a single follicle (Saunders, 2009) and a large bushy tail that is covered with coarser hair than the rest of the body.
Chinchillas have large thin skinned ears and have very sensitive hearing; they can be easily startled by loud noises and should be kept in a quiet room.
Handling
Chinchillas are shy nervous animals and may struggle when handled. Rough handling must be avoided as chinchilla fur is not tightly attached and can be easily shed. A large patch of fur is released leaving a smooth area of skin. This is a predator avoidance mechanism often allowing escape when caught and is known as fur slip. It can take several months for hair to regrow and it may regrow a different colour (Harkness et al, 2010).
The chinchilla should be caught in its cage and held gently round the chest with one hand with the other hand supporting the hindquarters. They should not be picked up or caught by the tail alone. Chinchillas should not be scruffed by the loose skin at the back of the neck as fur slip may occur and they may be dropped as a result. Care should be taken when removing chinchillas from their cage at the veterinary surgery as they are able to move at speed and can be very difficult to recatch.
Sexing chinchillas
Chinchillas can be sexed by lifting them as described above and placing the chinchilla vertically against your body to expose the genital area. In the male (Figure 2) the anogenital distance is longer than in the female (Figure 3). The urethral process in the female does protrude and can sometimes cause confusion.
Anatomy/physiology
Chinchillas have four incisor teeth with enamel which contains a yellow/orange pigment (Crossley, 2003). There are four premolars and 12 molars that form the cheek teeth. During chewing the jaw is moved diagonally forward and to the side sliding the upper and lower cheek teeth along each other grinding food in-between (Crossley, 2003). All of the chinchilla's teeth grow continually throughout their life and are worn down during chewing.
Chinchillas have a digestive tract which is highly adapted for the digestion of a low energy, high fibre diet. The digestive tract of the chinchilla is approximately 2.5–3 m in length. They have a large caecum where the microbial flora ferments the digestible fibre portion of the diet. The contents of the caecum are formed into caecotrophs (soft faeces) in the caecum which are eaten immediately following excretion. They contain Vitamin B and microbial protein which is absorbed by the chinchilla as it passes through the gut a second time.
Behaviour
Chinchillas are active throughout the night (particularly at dawn and dusk), and sleep during the day, although they can adapt to household schedules. They are vocal and produce a range of hiccupping noises, chirps, squeaks and barks (Saunders, 2009). Chinchillas are territorial and may spray urine at perceived intruders.
They are social animals and are likely to benefit from being kept in pairs or small groups (Figure 4). Aggression can occur between individuals when introduced and it is advisable to introduce animals that will live together at a young age or house siblings together. Aggression often occurs in same sex partnerships following the onset of sexual maturity, this may be reduced by neutering. Male-female pairings work well, however, neutering is required to prevent pregnancy in females not intended for breeding.
Handling from a young age is required to socialize chinchillas and ensure that they accept handling. Chinchillas not handled at a young age can be very shy and nervous around people, although biting and scratching are rare.
The chinchilla's response to fear or stress is to hide and they will often try to wedge themselves into a small space if a threat is perceived. Contact with prey species including cats, dogs and ferrets will cause stress. If kept in households where prey species are also present then the chinchillas should be kept in a separate room that other pets cannot access.
In common with other prey species, chinchillas do not readily display signs of pain. Chinchillas in pain will be quieter than normal and sit in a hunched up position. They will frequently stop eating and grooming themselves. Teeth grinding is also an indicator of pain. Biological data for the chinchilla can be found in Table 1.
| Lifespan | 10–15 years | |
| Adult weight | male | 400–500 g |
| female | 450–600 g | |
| Rectal temperature | 37–38°C | |
| Heart rate | 100–150 beats per minute | |
| Respiratory rate | 40–80 beats per minute | |
| Gestation | 111 days | |
| Sexual maturity | 6–8 months | |
| Weaning age | 6 weeks | |
| Oestrus cycle length | 40 days | |
| Litter size | 1–6 average 2 |
Diet
The natural diet consists of low quality fibrous plant leaves, stems and seeds found on the mountain slopes. Chinchillas have a highly adapted gut that allows them to get adequate nutrition from a low quality food source.
Chinchillas in captivity need a diet that is high in fibre and this is best achieved by providing good quality hay ad libitum. Like rabbits and guinea pigs chinchillas have continuously growing teeth and long fibre such as hay is required to wear them down and prevent dental disease.
Alongside this a small amount of chinchilla nuggets can be provided. The chinchilla nuggets are normally larger than similar rabbit and guinea pig ones because chinchillas like to pick up their food and larger nuggets are easier for them to handle. They generally contain 15–20% protein, 2.5% fat and 15– 35% fibre (Richardson, 2003; Saunders, 2009; Harkness et al, 2010). Over feeding of nuggets and treats (see below) can predispose to gut disease and cause obesity.
Small amounts of vegetables and low sugar fruits can be given as treats. Chinchillas have a sensitive digestive tract so new treats should be introduced gradually. Raisins are well liked but no more than two should be given a day (Richardson, 2003) as the high sugar levels may predispose to obesity and diabetes mellitus. Nuts and seeds should be avoided as they contain high fat levels (Richardson, 2003; Saunders 2009). Fruits with stones such as plums and cherries should be avoided as the stone may be toxic (Richardson, 2003), they are also high in sugar. Dried coconut should be avoided as it swells in the stomach resulting in a distended stomach and inappetence, which could prove fatal (Richardson, 2003).
Chinchillas consume 70% of their food during the night so it is important that adequate amounts of feed are left in the cage over night (Wolf et al, 2003). Clean water should be supplied at all times in either a bowl or chew proof water bottle.
Housing
Temperature/humidity
Chinchillas are well adapted to the cooler temperatures found in mountainous areas. They are best kept between 10–15°C (50–59°F). Above 25°C they become distressed and are prone to suffer heat stroke (see below) (Richardson, 2003).
Space
Chinchillas live in social groups and benefit from being housed with another chinchilla. Chichillas in same sex partnerships get on well as youngsters but aggression can occur when they reach sexual maturity. This may be reduced by neutering. Mixed sex pairs generally work well however neutering is required if they are not intended for breeding. Chinchillas that will live together should ideally be introduced at a young age to prevent the aggression that often occurs.
Chinchillas are an active, agile animal requiring space to exercise; they are able to jump so tall multi-level cages are ideal (Figure 5). Large cages of approximately 90 cm wide by 60 cm deep and 120 cm high are ideal for a pair. More space would be needed for more chinchillas. Uninterrupted heights of more than 60 cm should be avoided to reduce the risk of injuries from falls (Saunders, 2009). Galvanized steel wire mesh cages are frequently used for chinchillas but cheaper cages with visible beads of galvanized material should be avoided as there is a potential for zinc toxicity (Saunders, 2009). The mesh should not be more than 15 × 15 mm to reduce the risk of injuries to the feet from getting them trapped.
The floor of the cage can also be mesh allowing a tray to be placed beneath to catch urine and faeces to make cleaning out simpler, if this is the case a solid area should be provided in the cage to allow the chinchilla to spend some time resting of the mesh.
Chinchillas are shy animals and need to have areas in which they can hide and sleep. Wooden nest boxes, PVC or cardboard tubes can be provided. Chinchillas will gnaw on nest boxes so plastic should be avoided.
Chinchillas groom themselves in a dust bath (Figure 6); preventing dust bathing results in matted fur as oily secretions build up. Access to a dust bath should be provided daily unless there are recent traumatic or surgical wounds. The dust bath should be removed after use to prevent over grooming and conjunctivitis that can occur following prolonged exposure to the dust.
Many chinchillas benefit from having time out of their cages to exercise and to bond with their owner. Exercise areas need to be chinchilla proofed removing electrical cables and dangerous objects. Consideration should also be given to the fact that chinchillas can jump and raised surfaces need to be checked for dangers. Small gaps under and behind objects should be blocked up to prevent the chinchilla hiding out of reach. All exits (including windows) should be closed. As chinchillas are rodents it is likely that they will gnaw furniture in the room. Loose chinchillas should be supervised when out of their cages. The should not be let out in gardens.
Common diseases
The chinchilla is the longest lived of the domesticated small mammals and can live to be 18 years or older (Harkness et al, 2010). The average chinchilla lives 10–15 years and is generally very healthy. The majority of conditions that are reported in chinchillas are the result of poor husbandry or diet (Jenkins, 2010). The veterinary nurse can play an important role in educating clients about the correct way to feed and care for chinchillas to prevent many of the problems commonly seen in practice.
Heat stroke
Chinchillas are susceptible to developing heat stroke if environmental temperatures rise above 25°C, especially if humidity is also high. Chinchillas should be kept out of direct sunlight and away from radiators and heaters. Symptoms start with restlessness and increased drinking and progress through to collapse, difficulty breathing and open-mouthed breathing. A blood tinged frothy material may also be seen at the mouth and nose.
Affected chinchillas should be brought for veterinary assessment immediately and cooling started as soon as possible; animals should be cooled gradually by immersion in lukewarm water or wrapping in a damp towel and moved to a cool well ventilated area (Richardson, 2003).
Skin disease
Mites, lice and fleas are uncommon in chinchillas because they have dense fur (Longley, 2009). Other skin problems do occur and may result in chinchillas being brought into the veterinary practice.
Ringworm
Ringworm has been reported in chinchillas and presents with hair loss, dandruff, broken hair and reddened skin especially around the eyes, nose and mouth (Jekl, 2009). Infection can occur from direct contact with infected animals or indirectly from contaminated housing or equipments. Ringworm can affect people so precautions should be made when handling suspected cases.
Fur chewing
Fur chewing and patchy hair loss is seen commonly in chinchillas either as a result of self mutilation or chewing by companions. Hair loss generally occurs over the shoulders and sides of the body (Richardson, 2003), whiskers may also be chewed. This should not be confused with fur slip which leaves an area of smooth skin; fur chewing often leaves the dense undercoat giving a patchy dishevelled appearance. The causes of fur chewing are not fully understood and many factors are thought to be involved including overcrowding, stress, low fibre diet, dietary deficiencies and boredom. There may also be a genetic component as fur chewing is more common in some breeding lines. Providing a high fibre balanced diet and improving husbandry can reduce the problem (Richardson, 2003).
Matted coats
Chinchilla fur becomes matted when wet. It can occur in individuals that do not have access to a dust bath or are kept in a warm, humid environment. Fur can also become matted following handling with wet or sweaty hands. Mats of unmoulted fur may also indicate dental disease which can prevent chinchillas from grooming normally.
Digestive disease
Digestive disease is common in chinchillas and is often linked to poor diet with inadequate fibre levels (Harkness et al, 2010).
Choking
Choking occurs when an item of food (often a treat) or bedding becomes lodged in the oesophagus. It can present with coughing, retching, drooling and inappetence. It may be more common in chinchillas with dental disease as food may be swallowed whole because chewing is painful (Saunders, 2009).
Constipation
Constipation occurs when chinchillas eat a diet that is low in fibre and high in energy and protein. This may be due to a poor diet being offered or a change in the eating habits of the chinchilla. Often chinchillas will eat less hay when they have dental disease. In cases of constipation fewer faecal pellets are produced and those that are produced are often small, dark and misshapen (Saunders, 2009).
Diarrhoea
Diarrhoea occurs following the over feeding of fresh greens, high carbohydrate foods or mouldy hay, rapid diet changes, administration of some antibiotics and infectious disease (Saunders, 2009). It can be rapidly fatal and any chinchilla brought to the veterinary practice with diarrhoea should be seen as an emergency and intensive treatment including fluid therapy and nursing may be required.
Bloat
Bloat occurs when gases build up in the stomach following obstruction by an ingested foreign body or the rapid fermentation of food in a sudden change of diet, especially one high in fresh vegetation or fruit (Saunders, 2009). Affected animals are usually inappetent and lethargic and in severe cases may be collapsed or be found dead. Most affected animals require supportive treatment and treatment for the underlying cause.
Neoplasia
Tumours and cancers are rare in chinchillas and infrequently reported.
Diabetes mellitus
Several cases of diabetes mellitus have been reported in chinchillas. In common with other species it has been associated with obesity (Jenkins, 2010). Clinical signs seen include increased drinking and urination, weight loss, inappetence, depression and cataracts (Keeble, 2001). Treatment involves altering the diet to increase fibre and reduce carbohydrate, insulin injections have also been used (Saunders, 2009).
Renal failure
Renal failure is usually related to old age and is a common cause of death in older chinchillas (Jenkins 2010). Symptoms include weight loss, increased drinking and urination and urine scald. Treatment is supportive, and fluid therapy may be required to ensure that the chinchilla remains hydrated.
Dental disease
Chinchillas have teeth that grow approximately 5–7.5 cm a year throughout life (Richardson, 2003). Teeth are worn down during the process of chewing fibrous plant material (e.g. hay). If there is inadequate fibre in the diet then teeth become overgrown and can develop spurs along the edges which can cut into the tongue and gums causing inflammation and ulceration (Jekl et al, 2008). This often causes a reduction in the amount of food eaten, change in food preferences, weight loss and excessive salivation, which may cause matting of the fur down the front of the chinchilla. Affected chinchillas also commonly have an overflow of tears as the tooth roots also become overgrown and can occlude the tear duct preventing the drainage of tears into the nasal cavity (Crossley, 2001). This condition is called malocclusion and is seen commonly in domestic chinchillas (Crossley, 2001; Jekl et al, 2008). Malocclusion can often be prevented by feeding a diet that consists mostly of hay with commercial and fresh foods making up only a small portion of the diet. Malocclusion is treated by burring overgrown teeth under anaesthesia. Following treatment dietary adjustments described above should be introduced gradually to prevent recurrence. In many cases repeat dental treatments are required as the teeth cannot be returned to normal alignment.
Other reported dental problems include broken teeth, impaction of food in the mouth, caries. Congenital abnormalities are less common (Crossley 2001; Jekl et al, 2008).
Traumatic injuries
Fractures of the tibia have been reported following entrapment of a hind leg between cage bars (Donnelly and Brown, 2004). Fractures may also occur following falls as chinchillas will climb and jump to great heights.
Conclusion
Chinchillas are active social long-lived animals and can make attractive pets, however their requirements are often not understood by owners and poor husbandry and diet can result in disease. Veterinary nurses can play an important role in educating owners about the requirements of chinchillas and reduce the likelihood of them suffering many conditions.