Monday, March 16, 2015

How long do cats live?

Nelson was named after Nelson Mandela.

How long does the average cat live? It’s a question frequently put to me by cat owners and I confess until this week I’ve been basing the answer on experience (i.e. patients I’ve seen, cats I’ve known etc.). Fortunately that’s been vindicated by a recent report published in the Journal of Feline Medicine and Surgery(O'Neill et al., 2015).

The paper, based on data collected from just over 4000 cats in the UK, found that the average pet feline lifespan these days is around 14 years. The average cross-breed (moggy, domestic) cat lives longer than a purebred (by about 0.6 of a year, on average), but of course there is huge variation in individual lifespans. Birmans, Burmese, Siamese and Persians lived as long or longer than moggies, while Abyssinians, Bengals, British shorthairs, Maine Coons and Ragdolls had reduced longevity compared to the average.

The study has some very interesting findings. For example, the most common cause of death in cats five years or under was trauma, mostly motor vehicle encounters. These accounted for 47.3% of deaths in this age group.
In cats over five, the most common causes of death were kidney disease (13.6%), non-specific illness (12.6%), cancer (12.3%), and “mass lesion disorder” (11.6%). A mass lesion disorder was identified as a mass for which no diagnosis was made – so a mass might be cancerous, but it might also have been a cyst, inflammatory lesion or abscess. A number of cats with non-specific illness may have had cancer. The authors suggest that it is possible that cancer could account for up to one quarter of deaths in older cats.

Thinner cats lived longer. In cats over 5 years old, those that weighed under 3kg lived 1.7 years longer than cats weighing 4-5kg.

One major limitation of this and any veterinary study into longevity is that euthanasia may be elected by owners, and as such the stats may not reflect the natural lifespan of the cat. What we also can’t conclude is the role of husbandry – for example, whether diet, vaccination, indoor vs outdoor lifestyle or obesity are factors in determining longevity and if so, how influential are they? 

Obviously we know that cats with unrestricted outdoor access are at greater risk of getting hit by a car, and suffering other trauma including dog attacks or cat bite wounds.

It’s also hard to pick which cats will live longer. I’ve met young cats that develop cancer, and elderly cats that just keep on truckin’. The oldest patient I’ve performed surgery on was a 23.5 year old cat, who went on to live for another six months.