I’ve had the game for a little over four hours now and am currently playing campaign. So far, I have only discovered two terminals and no skulls. I have searched every nook and cranny for the skulls in the first four levels, but have yet to find them.
Has anyone who has the game, found any of the skulls yet?
UPDATE: I have located the famine skull. The level it is located on is the Silent Cartographer.
It is found after you deactivate the security controls (and it shows the cinematic of the Zealot running out of the locked door).
Head to the crash landed pelican outside of where the security controls are located (the pelican which drops the rocket launcher). Make your way to the top of the mesa located next to the pelican (the mesa which the nose of the pelican meets). After you make it to the top (via a ramp on the ocean side - there should be a few jackals and grunts guarding it), head to the end of it, make your way across the top and the famine skull should be there.
Haha thanks 
I guess I didn’t find those. But I think I might just find then myself.
what difficulty do you need to do for skulls?
> what difficulty do you need to do for skulls?
Well, I am currently playing on Heroic difficulty. But I would assume any difficulty > Easy (just like Halo 3)
thanks, in H2, you had to do legendary. It is good they are copying halo 3. I think it is the first time I am glad they have copied something from older halo.