From the Wikipedia article on the album art:

The album cover is a painting by Kevin Peterson. According to Peterson "The Red Hot Chili Peppers wanted to use my painting Coalition II for the cover of their upcoming album. I told em it was cool but not to hound me for autographs. Special thanks to Chloe and @Chelsea Marie Bradley for some fine modeling."

Anthony Kiedis in an interview on the Kevin and Bean show on May 5, 2016 discussed the album cover saying "Normally we get a little more high brow artsy, and this just felt extremely warm and human, even though it's animals, it felt human. And it's also us. Chad is the bear, Josh is the girl and Flea is the raccoon and me as the funny little raven out front."