In the thousands of years since dogs were domesticated, they have become more than just constant and valuable companions to humans. They have also become therapists, guardians, confidants, teachers, entertainers, and of course, friends. They make us laugh, drive us crazy, comfort us when we're down, keep us on our toes, and teach us things we didn't know about animals, about the world, about ourselves. Here's a small celebration of dogs in all their four-legged and furry glory.

P.S.: All the dogs photographed here were adopted through rescues or are currently with rescues and in search of forever homes. If you're looking for a dog of your own, there are many waiting in shelters all over the world.

cute small dog looking up at owner.
Dogs always appreciate our insights. (Photo: Jaymi Heimbuch)
white dog licking nose
Dogs are skilled at many things, especially counting treats. (Photo: Jaymi Heimbuch)
dog walking on log
Dogs are experts at companionship. (Photo: Jaymi Heimbuch)
senior dog
Senior dogs are simply expert dogs. (Photo: Jaymi Heimbuch)
Cute small dog with long hair
Dogs think we're just so very insightful. (Photo: Jaymi Heimbuch)
sweet pit bull dog with quote
Understanding dogs mean learning more about ourselves. (Photo: Jaymi Heimbuch)
dog reading book with quote
Dogs and books are everyone's BFFs. (Photo: Jaymi Heimbuch)
small dog on leash
Having a dog makes you rich, even if you have nothing else. (Photo: Jaymi Heimbuch)
pit bull puppy
Unconditional love, and puppies!! (Photo: Jaymi Heimbuch)

Jaymi Heimbuch is a writer and photographer at Mother Nature Network. Follow her on Twitter, Google+ and Facebook.

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Jaymi Heimbuch ( @jaymiheimbuch ) focuses on wildlife conservation and animal news from her home base in San Francisco.