CHICAGO (CBS) — Most dogs are man’s best friend. A 3-year-old Dutch shepherd from Chicago didn’t stop there, he’s friends with everything — even a rat.

Once you find out more about Osiris, things begin to make sense. Osiris is trained to be extremely gentle with baby animals, explained Mickey Alice Kwapis, his owner.

READ MORE: Chicagoan David Kronfeld Shares Advice To Career Success In New Book

“Osiris is trained to … be very gentle and help keep orphaned baby animals warm because heating pads can actually cook them to death,” Kwapis explained. “I do a lot of foster care and wildlife rehab (I am licensed to do so, it is illegal and dangerous without training) and Osiris helps us with all the little guys.”

“He’s been the sweetest guy since we found him abandoned in a parking lot as a tiny puppy almost three years ago,” Kwapis went on. “Since then, he’s helped us with rehabilitating mice, Riff Ratt (whose eyes weren’t even open when we rescued him), squirrels, kittens, raccoons and puppies.”

And to be clear, 3-month-old Riff Ratt isn’t the typical rodent seen in many of Chicago’s alleyways. Domesticated rats like Riff Raff aren’t only as clean as your pet dog or cat, they also tend to be quite friendly and affectionate.

READ MORE: AAA Provides Best And Worst Times For Post-Holiday Travel

The Instagram for Osiris and Riff Ratt is a testament to how chummy these two pets legitimately are. The many photos show Osiris and Riff laying with each other, and even licking each other.

In one photo, Riff is even inside of Osriris’ mouth, reminiscent of a lion tamer who’s put his head inside the jaws of a well-trained beast. According to the owner, this is typical. “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. See for yourself!”

See more photos of Osiris and Riff Ratt here.

MORE NEWS: Chicago Weather: Sunny, Breezy With Seasonable Temps

Mason Johnson is a Web Content Producer for CBS Chicago. You can find him on Twitter.