A small guideline for choosing a rat as a pet:

1. Avoid purchasing any rat that appears ill, quiet or depressed. They should be bright and alert, and move quickly when startled. They shouldn't appear hunched up.

2. Beware of pets with closed eyes or discharges from the eyes or nose as thin usually indicates some kind of illness.

3. Check the mouth for drooling saliva or wetness to the fur, this may indicate badly positioned premolar (cheek) teeth.

4. If you can (and the rat will let you!), examine the incisor (front) teeth and make sure they are not overgrown or digging into the lips or gums.

5. You should be able to feel the ribs with just a small amount of fat over them.

6. Check the anal area for diarrhoea, soiling or moistness, which might indicate a gastrointestinal infection.

7. The skin should have an even coat of fur and no signs of scratching or wounds.

8. Lastly, a good pet shop will offer a health guarantee that requires a check-up by a veterinary surgeon within 48 hours of purchase. Most good Veterinary Groups will be happy to provide this check up for you.

Sounds lovely, eh?