ALTHOUGH the concept of Peter Pan is very heartwarming, it is unfortunately an undeniable fact that as time goes by every living thing does get older. All living creatures have a certain life expectancy, and as that time approaches, the effects of ageing become apparent.

While humans now expect to live to about 80 or so, dogs' life expectancy varies with breed. Most dogs will live for between 10 and 13 years, and the small breeds survive longer than the large. Great Danes and St Bernards, for example, do not usually reach 10 years, and Bulldogs rarely reach seven or eight. On the other hand toy breeds and small terriers often live between 14 and 17 years. Reports of some dogs living for over 20 years are occasionally heard.

There is an old theory that one year of a dog's life equals seven of a human's, but this is based on the assumption that a dog lives to 10 and a human to 70. A much more accurate comparison would be as follows:

Dog age Human age Dog Age Human Age

3 months 5 years 8 years 48 years

6 months 10 years 10 years 56 years

8 months 13 years 13 years 64 years

10 motnhs 14 years 14 years 72 years

12 months 15 years 16 years 80 years

18 months 20 years 18 years 88 years

2 years 24 years 20 years 96 years

4 years 32 years 21 years 100 years

As dogs get older, just like humans, they undergo physical and behavioural changes. Older dogs are less energetic and curious and are generally more lethargic. They sleep more and are less tolerant to changes in routine and surroundings, showing crankiness and irritability.

Arthritis caused by the gradual deterioration of the cartilage lining the joints is a common problem in older dogs. Stiffness of the joints causes pain and discomfort - particularly when the dog rises.

Animals suffering from this should be given gentle exercise more often but for much shorter periods. This may lead to their nails becoming too long and needing regular clipping. The loss of subtlety in the joints makes self-cleaning and grooming more difficult and your dog may need help with this.

Providing a padded surface on which your pet can sleep will help. Some very good products are available, in either tablet or oil-based form, containing glucosamine, which helps alleviate arthritic discomfort.

Older dogs, just like humans, develop grey hairs and can become incontinent. Their self-temperature regulation is less efficient so it is important to ensure your dog's bed is warm and draught-free, and avoid leaving him outside in the kennel in cold weather. The use of a dog coat is a good idea.

The loss of muscular tone and reduced activity may result in the neck and body becoming more bulky. Older dogs need less calories because of reduced activity and it is wise to feed them with a special, good-quality 'senior' diet that will prevent obesity but still provide all the essential nutrients it needs. Some also contain ingredients, which help keep joints subtle.

Other problems which become more common in older dogs are cancers and tumours, kidney disease (usually characterised by increased thirst), heart valve trouble and bacterial infection of the urine leading to cystitis.

The senses become less sharp in old age and often the lens of the eye becomes opaque. This condition, however, does not necessarily impair vision.

Like all 'golden oldies' nearing the end of their natural life, plenty of tender loving care is what is needed, and the vet is always the best person to advise on what is ultimately best for your old dog.