Cats don’t have nine lives and neither do dogs. Obviously they both have one life unless you believe in and include the afterlife or reincarnation which I am not doing here.
“A cat has nine lives’ is simply a saying which means that inquisitve domestic cats take risks and often survive those risks because they are very agile, able and athletic. They also have high levels of endurance and persistence and are able to survive difficult times. Because of this ability to survive due to their athleticism and other attributes, in ancient times nine was considered a particularly lucky number because it was a “Trinity of Trinities” and therefore ideally suited to the “lucky” cat.
Of course this was not luck but it looked like it to observers. It was, as stated, more about the cat’s abilities which can sometimes be exceptional as to be unbelievable. Survival was put down to good luck.
There is another aspect to the domestic cat which might have influenced people to think of cats in this way. In ancient times domestic cats were, in general, less domesticated. People understood them less well and they were more mysterious. There was more superstition than today. This lack of knowledge must have been a good incubator for the idea that cats escaped death in a magical way. The concept of the Trinity of Trinities is also somewhat magical.
To put it another way, at the risk of boring any readers, the concept of a cat having nine lives is simply a recognition of their abilities. It is a label which has stuck over the centuries.
The reason why dogs have not been given a similar label is because they are not known for their very high agility or their exceptional athleticism which can get them out of difficult situations. Although dogs have far better stamina in terms of running abilities. Dogs are also less mysterious and enigmatic. They are in your face. Also in ancient times dogs were far more utilitarian. They were working animals. Perhaps they were worked to death leaving no room for the imagination to believe that they could evade death like the enigmatic cat.
P.S. The first domestic cats were utilitarian too….
SOME PAGES ON WORKING CATS: