WATCH: Cheetah cub and puppy become BFFs at San Diego Zoo

Friendship can come in all sizes, shapes – and even species.

Take the example of Ruuxa and Raina, two youngsters at the San Diego Zoo Safari Park who met when they were four and five weeks old, respectively.

Of course, we should probably mention that Ruuxa is a four month-old cheetah cub – and Raina is a Rhodesian Ridgeback puppy.

And not only are the two inseparable, but zoo staff credit their unique bond with helping Ruuxa recover from serious surgery.

That’s because Ruuxa suffered from a growth abnormality in his front legs, causing a “bowing” of the limbs and making standing, walking, and running extremely difficult.

It also meant the young cub had to undergo a serious surgical procedure – something zoo staff say he could not have bounced back from as quickly without Raina’s help.

And while it may seem like an odd pairing, zoo staff say it’s common practice at the park to pair up cheetah cubs with more domesticated animals, so that the young cheetah becomes used to human interaction.

“Cheetahs interpret most things that are normal as dangerous things they want to avoid, so to help them get over that we bond them to a domesticated dog,” Rose-Hinostroza said.

Still, park officials say they’ve never seen a pairing take root at such a young age.

“They’re more like siblings than friends.”

As for Ruuxa, he’s expected to make a full recovery – thanks to a little help from a friend.