What are the commonly accepted loading patterns in data intensive IOS apps these days?

So I have a app with a bunch of loading screens, all remain under 5 seconds, but compared to apps like Instagram, Yik Yak, FB, Twitter....its a worlds difference. Idt I see a loading dialog beyond the initial splash no matter where in the app I go initially in any of these apps. Is there a commonly accepted pattern to loading data into a app beyond the initial screen a user lands on on open?

Are they doing requests in the background? Are they doing one giant request initially thats considered acceptable if you provide a user with a splash screen?