According to the American Society for the Protection of Animals, cats, including tortoiseshell cats, tend to live between 13 and 17 years. They can live to be over 20 years old with proper care.
Tortoiseshell is a color, not a specific breed of cats. For this reason, tortoiseshell cats have the same average lifespan as any other cat. Color does not affect the lifespan of a cat, so a tortoiseshell cat can expect to live 13 to 17 years or longer. Paying close attention to health, including regular vaccinations and checkups with a veterinarian, can help ensure a long lifespan for a tortoiseshell cat.