Here's why:
* Average gestation: The average gestation period for cats is 63-67 days.
* Individual variation: Just like humans, cats can have slightly different gestation periods. Some might give birth earlier, and some might carry their kittens a little longer.
* Stress and health: Factors like stress, poor nutrition, or underlying health issues can sometimes lead to premature births.
Important Note: If a cat is giving birth significantly earlier than 63 days, it's crucial to seek veterinary attention immediately. This could indicate a health issue for both the mother and the kittens.