My veterinarian says my dog has a navel but I’ve searched his belly and I just can’t find his belly button anywhere! Even after he had surgery that required the vet to shave him in that area there wasn’t any navel. Are dog belly buttons completely different from hairless ape belly buttons?
There’s usualy a swirl of hair around a dog’s navel. It may only show up as a lightening of the skin. It will be even with the rest of the skin, not an inny or an outy.
Look just past half way the page. You will see a nurse tying off a canine umbilical cord on a newborn puppy. Make necessary adjustments for your dog’s topology and look approximately there.
My dog has a particularly sparse cover of hair on her tummy, and if you were to draw an imaginary line between front left and rear right, and front right and rear left legs, then the intersection would be close to it. Or perhaps about an inch back towards the tail end.
It doesn’t look like a human one - not an innie or an outie, but more like a bit of disturbed / scarred skin.
If it is really important to you, I can take a picture of it 
Hmmmm, a money making opportunity: dognavels.com 
P