For mid-20th century DC Comics, there was one surefire way to raise sales: Stick an ape on the cover and make readers ask why. And it still works! Go on - pretend you don't want to read these stories.
The origin of the ape meme was very down to Earth, according to DC artist Sheldon Moldoff, who explained it to the Comics Journal:
It was a question of trying to find something that sold, and if one issue came out and it happened to sell, then immediately they would follow that type of story. Now, it didn't neccessarily follow through that they were going to sell. Now, I know Jack Schiff, when he was the editor of Batman, he followed sales very well. When he found that a gorilla on covers sold, then you could be damn sure that in an issue or two you're going to have another gorilla story.
We can understand the logic of wanting more gorilla stories, but there's no denying that some kind of weird genius came into play when deciding that these were the kinds of gorilla stories that readers wanted:
The trend didn't even die out as the audience started to grow up. Sure, ape appearances became fewer and far between, but before too long, DC's Ape History had become something that the publisher embraced, somewhere between affectionate parody and outright nostalgia:
In fact, there's even a collection of some of the best ape-related superhero stories for those who're curious... But we're waiting on one that'll finally tell us whether John (Gorilla) Doe was finally found innocent or not. Surely that injustice cannot stand?!?