Owls come out at night. It is more correct to say "during the night". e.g. During the night I woke up because I was thirsty.

I worked 'at night' while the thief works 'in the night'. I mean "at night" here as referring to the nature of my job (here in our country, a call center agent really works at night as they always communicate / do business with Westerners). the thief on the other hand works "in the night" as to mean 'during the night' or while the night was passing (of course, he may find it hard to execute his evil plans during day light, huh?). sometimes though, these two are interchangeably used. :)

He walked into the darkness of the night alone.