You may not know their heritage, but mixed-breed dogs are just as great as (and some might say better than) any purebred. July 31 is National Mutt Day, a holiday to celebrate and raise awareness of these fantastic canines. To honor the day, we gathered up some of our favorite fan-submitted photos of mixed-breed dogs.

Soupie the Rottweiler-German Shepherd mix is a total ham. And he should be! He’s one handsome fella.

Oz just photobombed Grommet. Nice one, Oz.

Zephyr the Lab mix's puppy dog eyes are simply irresistible. 

Quick! Guess which dog breeds and mixes are represented in this photo. From front (right) to back: Nina the Papillon-Doxie mix, Tito the Chihuahua, Pepito the Pomeranian, Jasmine the American Eskimo-Lhasa Apso mix and Gypsy the Corgi-Shih Tzu mix.

Tango is a shepherd mix. His owners think he's also part kangaroo. We couldn't agree more: The marsupial resemblance is uncanny.

Rudi is a 7-year-old Lab mix who loves bananas, cuddles and sniffing the cat. She's also quite the dreamer — hardly a night goes by when she doesn't move her legs and bark in her sleep.

Maya, a Min Pin-Chihuahua mix, is a snuggling pro.

Banks the terrier mix is the coolest dog in L.A. He's even got the Mohawk to prove it!

He has only three legs, but you wouldn't know it from Tre the Husky mix's huge smile.

Frankie the Shih Tzu mix can't get enough of his favorite bunny toy.

Nothing — and we mean nothing — will keep Frida the hound mix from her beloved tennis ball.

Dixie the American Staffordshire Terrier-Boxer-American Bulldog-Rottweiler mix's owners made her a Dog of Honor bandana to wear for their engagement photos.

Baxter and Bailey the Golden Retriever mixes have such great noses that their owner thinks they could've had successful careers sniffing luggage for the TSA.

We can tell that Clover the Westie-Jack Russell Terrier mix is one happy puppy.

Bobo the 1-year-old Catahoula mix is full of energy, but there's one thing that calms him down: a Kong stuffed with peanut butter.