If you ever thought your cat was a sly, complicated creature that seems to be keeping a secret or two from you…. Well… You’d be right. In fact, we’ve counted at least 20 amazing facts about your favorite feline friend that you never knew about. So read on, and learn what that purr really means.

Female Cats Are Usually Right-Pawed

After testing 42 cats—21 male and 21 female—psychologists D. Wells and S. Millsopp of Queen’s University Belfast determined that cat’s dominant paw is correlated with gender. For the record: Female cats? Right-pawed.

Cats Have Over 20 Muscles That Control Their Ears

Cats can hear even the slightest rustle because they have over 20 muscles that control the exterior part of their ear. Also, a cat can figure out the source of the sound more accurately when it’s not moving—which explains why it often stops and listens, utterly frozen.

Cats Sleep 70% of Their Lives

Domestic cats do mostly one of four things: sleep, eat, run, or play. It turns out, sleeping takes up more time than the other three activities combined. Cats are among the top-sleeping in the animal world because in the wild they must use a lot of energy to hunt.

Cats Can’t Taste Sweetness

Cats are only interested in meat and are not tempted with sugar or spices. They lack the ability to taste sweetness—unlike just about any other mammal.

Having a Cat Can Reduce Your Risk of Heart Attack or Stroke by a Third

Having a cat helps release stress and anxiety, which is known to lower blood pressure and protect against heart problems.

A Purr is a Sign of “Self Healing”

The purr is often translated as a sign of contentment, but it may be more complex than that. Not all purring is related to pleasure—in some cases it reflects pain or nervousness. And some experts believe it’s a sign that their muscles and bones are recovering.

Cats Are Often Lactose Intolerant

Even though most cats love milk, it doesn’t mean that milk loves them back. Cats have trouble digesting lactose, which can upset their stomachs and lead to diarrhea.

Raw Fish Can Be Bad for Cats

Another delicacy cartoons would have you believe cats love is raw fish, which may actually be bad for them. Uncooked fish can contain bacteria that are harmful to cats and can cause food poisoning. Also, an enzyme in raw fish destroys thiamine, an essential B vitamin, which can lead to neurological problems.