Собака и Кость
Однажды мужчина увидел собаку с костью. "Почему, собака, вы жеваешь эту кость; у неё не мяса". "Я жеваю кость, потому что хочу мои зубы всегда быть резкими", ответилa собака, тогда показалa свои резкий зубы к мужчине, который скоро ушёл от собаки.
Мораль - У каждого свое ремесло.

The Dog and the Bone
One day a man saw a dog with a bone. "Why, dog, are you chewing that bone, it has no meat'. "I am chewing the bone because I wish my teeth to be always sharp", answered the dog. Then he showed his sharp teeth to the man, who quickly left the dog.
Moral: Each person has his own craft.

Incidentally, the English version is a literal translation of the Russian.
Also by the way, dogs live for about 10 years; neither I, nor a dog lover I just talked to, has ever known of a canine that completed its allotted span of years without keeping all of its teeth. On the other hand, who knows of a seventy year old man who still has all 32 of his cutting and grinding tools?