Did my dog notice when I dyed my hair?

question too confusing, dick caught in ceiling fan

I'm sure she tilted his head a bit, wondering what's up? And, she most likely missed your before hair color change (familiar) hair smell too. Recent scientific research from Emory University’s Department of Psychology, found that dogs are able to recognize human and dog faces. That's pretty remarkable, so even though your hair color  has changed, rest assure she knows your face, voice, and scent.

He did he loved it 

I agree with the overall consensus that dogs would notice a different smell vs. noting a change in hair color. 

But, we had to have a very matted rescue sheepdog mix shaved that our dog knew quite well after 2+ weeks of staying with us and when we brought the pretty much hairless dog back, our dog (and cat) didn't seem to recognize her at all (at first).

 Of course, she obviously smelled different (having been washed/groomed/shaved) but the startled reaction was from a distance (front door to way into the kitchen). It was hilarious and I wish I would have thought to record it. They looked absolutely shocked. So, I don't think it's out of the question that your dog wouldn't note a change in your hair color. The residual smell of peroxide bleach and toner would likely be noted (even if you can't smell it, he/she can). 

He recognizes you by your familiar scent. Dogs can only see in black-and-white or sepia tone so differences in color would not stand out just varied range of shades and tones.

Your dog knows you more by scent. 

Dogs know you primarily by your scent, they same way they recognise each other.  She knows you by your voice too, but your scent is the most important thing to the dog.  She probably does notice that your hair has changed and just chalked it up to "something" having happened to you.  She's not wrong either.

Your dog probably goes by scent, so still recognizes you, just as we still recognize a person when they change shoes.

It's possible, some pets notice when you change your hair. Your dog most likely knows it's still you, they just have to learn to adapt to the changes. 

My cats gave me strange looks when I bleached my hair a few years ago, but they know it's still me. 

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