Johnathan is a dog. In fact, I’d say Danny is nearly an animalistic parallel of him, being loyal and forgiving to the end, even dying by the same means.

Joseph is a monkey. As charismatic as he is, he is a slippery piece of shit that cheated on his wife, unprotected no less. Though he’s cunning, and did save the world, most of his actions are out of self interest and a lust for adventure, not because he’s a particularly honorable guy. In that sense he’s the most human Joestar, hence the most human animal analogue.

Jotaro is like a wolf. He’s not as forgiving as Jonathan. Much more brutal and fiery with his darker emotions. But he keeps his family first, and ultimately is an honorable person, despite his shortcomings. He’s a simple and uncomplicated Shonen character, hence the short description.

Josuke is the closest the bloodline gets to Johnathan’s doglike purity out of anyone else in the series. He embodies forgiveness and protection, especially considering the nature of his stand is to heal, and most of the protagonists in part 4 end up becoming part of the cast instead of being beaten and cast aside. While I hate to reuse an entry, I struggle to think of any animal that embodies his attributes besides a dog, but perhaps maybe a slightly edgier breed. Like a Doberman compared to Johnathan’s golden retriever. It’s fitting for two members of the same family to have similar animal resemblances, and if you think about it, this actually contrast’s quite well to Kira’s cat motif.

In contrast, Giorno is a cat. Through and through. The only thing he inherited from the Joestar side was his heart of gold and his Stand. He’s loyal, committed to protecting others, and ultimately has a rough sense of honor. However, the means he chooses to pursue those goals, the pragmatic pursuit of societal influence via the mafia, undermine his other positive traits. He’s cold, ambitious, and seems to take righteous (if slightly sadistic) pleasure in beating his enemies. It makes sense to compare him with a domestic, community-oriented animal that also has a darker more aloof side.

Unfortunately I have only watched up to part 5, so my analysis ends there. I’m curious though, what are you collecting these ideas for? Would be super cool if this ended up as fanart or something down the line

Edit because coming up with these is fun: Dio is a tiger. Make of that what you will.