If there's one thing we truly love at Woof Woof, it's seeing the unlikely friendships that can blossom between two unfamiliar species — and dogs seem to be pretty awesome at doing just that.

Osiris and Riff Rat are best friends who are completely inseparable despite their huge size gap. Osiris is a 5-year-old Dutch Shepherd, while Riff Rat is as his name would suggest, a 7-month-old rat. The partners in crime can't stand a second apart and the level of trust they have for one another is mindblowing!

Riff Ratt and Osiris, the unlikely friends who have become inseparable. The strange but endearing friendship started back then Osiris's owners rescued 4-week-old Riff Rat. He was so fragile and small, he hadn't yet even opened his eyes and needed to be nursed back from the brink with the use of a syringe.

Osiris helped nursed Riff back to full health. Osiris himself was actually a rescue himself who was abandoned in a parking lot when he was just a little pup. When the family took him in temporarily, they fell head over heels for him and decided to keep him forever — so it would stand to reason that he would take well to a fellow rescue. Osiris helped nursed Riff back to full health. Osiris himself was actually a rescue himself who was abandoned in a parking lot when he was just a little pup. When the family took him in temporarily, they fell head over heels for him and decided to keep him forever — so it would stand to reason that he would take well to a fellow rescue. Osiris helped nursed Riff back to full health. Osiris himself was actually a rescue himself who was abandoned in a parking lot when he was just a little pup. When the family took him in temporarily, they fell head over heels for him and decided to keep him forever — so it would stand to reason that he would take well to a fellow rescue. Osiris helped nursed Riff back to full health. Osiris himself was actually a rescue himself who was abandoned in a parking lot when he was just a little pup. When the family took him in temporarily, they fell head over heels for him and decided to keep him forever — so it would stand to reason that he would take well to a fellow rescue. Osiris helped nursed Riff back to full health. Osiris himself was actually a rescue himself who was abandoned in a parking lot when he was just a little pup. When the family took him in temporarily, they fell head over heels for him and decided to keep him forever — so it would stand to reason that he would take well to a fellow rescue.

Osiris is now a trained therapy dog and he has helped his family look after lots of different animals over the years. Admittedly, Osiris' parents were really worried that the two wouldn't be able to stand each other – or even worse, that the pooch would try to hurt Riff in some way. After all, Osiris is a huge dog and Riff is a tiny rat.

However, those fears were completely unnecessary as it didn't take them long to hit it off. They're so close in fact that Osiris even lets Riff crawl in his mouth and clean his teeth for him. "Riff Ratt really likes licking the inside of Osiris' mouth. I'm sure you all are wondering if we're afraid Osiris will eat Riff – NOPE! Osiris has helped foster and care for dozens of animals and he is the gentlest dog I've ever met," their owner said on Instagram.

Not only do they like to hang out and spend time together, but they're not afraid to show affection for one another. They're pretty much inseparable! This duo's friendship knows no bounds. Just look at these two adorable friends just having a great time together. They're not afraid to show how much they love each other. "Oh yeah, that's the spot. Right there, Osiris."

It sure seems that Osiris doesn't mind giving Riff Ratt these adorable little baths either. He must like keeping his best friends clean, how else could you explain it? "Seeing them care for each other and have such an unexpected friendship gives me a tiny bit of hope for the rest of the creatures on this planet — especially humans :)," If Riff and Osiris made you smile, please SHARE their story with friends below.