He 'kept/maintained his cool' [=he didn't get angry or upset] even though it was clear that he was being unfairly treated.
He was struggling to 'maintain his cool/composure'. [=he was struggling not to become angry or upset]
They barely had enough food to 'maintain life'. [=to make it possible for life to exist or continue]
(..) I'm afraid your hunting activities have caused something of a mess for us. Our apologies. We didn't realize the territory had been claimed. Yes, well, we maintain a permanent residence nearby. Really? Well, we won't be a problem anymore. We were just passing through. The humans were tracking us, (..)2008 Twilight