The odd couple: Dog and duck make unlikely best friends

A dog and duck make unlikely best friends.

Man's best friend? In this case, a dog is a duck's greatest pal.

A duck has been hanging out with a dog for three years now, hitching rides on its canine friend and faithfully following the dog around.

Reddit user I2izzo posted a series of photos of the odd couple on imgur.

"The duck is too fat to fly and has since claimed the dog as his lifelong mate. Wherever the dog goes the duck will always follow," I2izzo wrote, adding that the sweet friendship has been going strong in St. Louis, Missouri "ever since the duck was old enough to roam on its own."

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Other adorable unlikely duos we've seen here:

Kate, a Great Dane, and Pippin, the abandoned fawn she adopted.

Western gray kangaroo Love Bug and Dozer, Love Bug's canine best friend.

A cat befriending dolphins.

The inseparable pair of Duder the dog and Mac the horse.

These inter-species friendships have plenty to teach the rest of us. Why can't we all just get along?