Josie, the author's dog niece, has dark, friendly eyes. Maria Osborne Human pupil size tends to decrease with age, because the muscles that respond to light lose some of their strength over time.

The simple conclusion was that dark eyes on a dog tend to send a non-threatening and more inviting gaze signal to human beings. Those soulful brown eyes might stir some, people to write poems ...

Humans tend to prefer dogs with darker eyes, scientists have found, which could be linked to how they evolved from wolves. Dogs evolved from their closest relatives, gray wolves. Over time, they ...

Like dogs, they also have this tapetum lining, which reflects light and boosts their night vision. If you’ve seen your cat or dog’s eyes glowing in the dark, this is what you’re seeing.

Dark-eyed dogs are rated as friendlier and more puppy-like. Brown eyes may have been specifically selected for during the domestication of dogs.