Species-specific diets for small mammals

A variety of small mammals, such as rabbits, hamsters, gerbils, guinea pigs, rats and chinchillas, continue to be popular household pets for people of all ages. Indeed, in the most recent survey there are estimated to be around 1.5million homes keeping them as pets.

Posted: 19 March 2020

Species-specific diets for small mammals


The 2019 Pet Food Manufacturers Association Pet Population Report, which looks in detail at pet ownership trends, found that of the 12 million UK households with pets, the breakdown of households with small mammals was;

  • 600,000 rabbits
  • 400,000 guinea pigs
  • 300,000 hamsters
  • 100,000 rats
  • 100,000 gerbils

There is no doubt that owners are increasingly expecting the very highest quality of veterinary knowledge and care. Our understanding of medical conditions is taken for granted, but we are also expected to be able to inform and advise on diet. After all, nutrition is the key to a healthy pet, and it should provide all the necessary requirements for animal maintenance and growth.


Clean water must be available and accessible at all times. Some species require less water due to their physiological adaptations to living in a dry environment (e.g. gerbils and chinchillas), but they still need a reliable clean source of water. All containers, whether they are water bottles or bowls, should be emptied and refilled daily.

Have you read our article on Water consumption and preferences?

What are the species differences in nutrition?

A. Rabbits

Some key features of the rabbit gastro-intestinal tract include;

  • Small intestine – the duodenum, jejunum and ileum, which form the small intestine, is essential for digesting carbohydrates, proteins and fats.
  • Large hindgut – the caecum and colon are the main part of the rabbit gut involved in digesting and processing fibre.
  • Ileo-caecocolic junction – this is adapted for mixing and separating large quantities of grass and hay.
  • Haustra – the contractions of the musculature in the walls of the proximal colon and caecum sort the material into indigestible and digestible fibre.

A common mistake people make when feeding rabbits is to overfeed calorie and starch rich foods and underfeed high fibre foods such as hay and greens. Ultimately this will lead to obesity and gastrointestinal disease. 

The most important part of the house rabbit diet is an unlimited supply of grass and hay, which provides essential fibre as well as being a source of proteins, vitamins, minerals and carbohydrates.

A high-fibre diet, based on good quality hay and supplemented with leafy greens such as dandelions, herbs, broccoli and cabbage, will provide all that is required. The fibres can be divided into;

  1. Indigestible fibre – this has little nutritional value and is excreted rapidly in the hard faecal pellets. It is however an essential ingredient as it stimulates intestinal motility and keeps ingesta moving rapidly through the gastrointestinal tract. If the diet is deficient in indigestible fibre, the animal is at great risk of gut stasis.
  2. Digestible fibre – the main digestible fibres, hemicellulose and pectin, provide most of the nutritional value to the rabbit. Fibrolytic bacteria, yeasts and protozoa in the caecum break down the fibre, releasing volatile fatty acids (VFA’s). These are absorbed and provide an energy source for the rabbit. The remaining caecal contents are formed into caecotrophs, which contain microbial proteins and essential vitamins. Once ingested, the redigestion of caecotrophs enables the absorption of previously undigested nutrients to get maximum nutrition.

At Burgess Pet Care we produce some of the highest quality Timothy feeding hay available, which is rich in all the essential fibres. Our Burgess Excel Long Stem Feeding Hay is our premium hay and has some key benefits.

7 Key benefits of Excel Long Stem Feeding Hay

  1. High in fibre – all fibrevores need a reliable source of good quality digestible and indigestible fibre. Timothy grass hay provides this.
  2. Low in sugar – we need to avoid feeding high carbohydrate and sugars to hind gut fermenters.
  3. Dust free – the grass is air dried in a controlled manner. This avoids the grass becoming too dry and dusty.
  4. Mold free – by air-drying the hay and monitoring the moisture levels, we prevent the hay being stored and packed with a moisture content that is either too high or low. This prevents any mold spores from forming and so avoids the risk of allergic or fungal diseases, not to mention mycotoxicosis.
  5. Palatable – the hay is cut at full bloom before it becomes too old and woody. This ensures a fresh, fragrant and colourful product that retains a very high palatability.
  6. Quality controls – we test our hay for nutritional content, so you’re assured of the quality of what is being offered.
  7. Weed free – our fields are monitored for unwanted weeds such as ragwort.

See our full Hay range>

Remember that carrots, which are high in sugar, should only be offered in small quantities. The leafy green tops are more beneficial than the root vegetable itself!

B. Rodents

The two main groups of rodents we see as pets are Myomorpha and Hystricomorpha. Essentially these are;

1. Myomorpha (rats, mice, hamsters and gerbils)

These animals are classified as omnivores, eating roots, leaves, grains and even small invertebrates in the wild. They have a simple stomach, a much smaller caecum compared with herbivores (there is much less need for fermentation of high-fibre food) and an elongated colon.

Coprophagy is also normal behaviour with rodents, but unlike rabbits, they ingest these caecal pellets from the floor.

These small rodents have very different nutritional requirements when compared to rabbits, and as pets are best provided with a commercially prepared species-specific diet. A measured amount of this food should be offered daily and supplemented with small amounts of vegetables and fruit. Since they are omnivores, it’s also recommended that a small portion of a protein source should be offered each week, using foods such as hard-boiled eggs or cheese.

At Burgess Pet Care we produce species specific rodent food. Our range includes;

When feeding these complete diets, it helps with exercise and mental stimulation if you scatter the food to encourage the natural foraging behaviour.

The most common form of malnutrition in these species is obesity. Unfortunately, many owners feed an excess of food relative to the animal’s size, which when combined with limited opportunities to exercise, leads to;

  • Obesity
  • Hepatic lipidosis
  • Cardiac disease

B. Hystricomorpha (guinea pigs and chinchillas)

These rodents are true herbivores, and in the wild will feed on a high-fibre diet consisting of grass and plants. They have a glandular stomach, large caecum and long intestinal tract. Like the other rodents, they also produce caecotrophs. Their diet should consist of;

  • Hay – only feed a good-quality dust free hay.
  • Leafy greens and vegetables – freshly picked dandelion, spinach and broccoli are ideal.
  • Species specific pellets – these are used to avoid selective feeding.

Sugar rich treats should be avoided as these can lead to dental caries.

Hypovitaminosis C in guinea pigs is a condition which results from feeding diets with inadequate levels of vitamin C. As a species they have an absolute minimum dietary requirement for vitamin C of 10mg/kg per day, rising to three times this amount during pregnancy. The guinea pig products we produce at Burgess Pet Care are fortified with Vitamin C. These products include;

Have you read our article on Vitamin C deficiency in Guinea Pigs?

See the food we produce for chinchillas >