Scientists used to think that only people were right- or left-handed. But new evidence shows that apes, cats, dogs and even birds have this characteristic, too.

In dogs and cats, females tend to be right-handed, whereas males are south paws. Some cockatoo species are left-footed.

There’s a relationship between the hand, paw or claw favored and which eye dominates vision. It’s easier and quicker to reach for something right in front of you, so those with left-eye dominance tend to use their left hand. This becomes a habit reinforced by repetition.

Handedness can also reveal which side of the brain predominates, with right-handed people using mostly their left brain, and vice versa.

No one knows which side makes for the best thinkers. But one thing is for certain, the best pets can be righties or lefties.