He(Marine) called me "baby" what is he trying to tell me?

He's in the military. We went to high school together and haven't seen him over a year. we started talking about 2 months now. and been talking nonstop ever since. its cute how he find time to talk to me.. he's going to Afghanistan in 4 months:/ he said he'll give me his dogtag to keep and stuff.. he been calling be " baby " idk why because we're not going out.. what is he trying to tell me? because idk if i should say it back:/