Is it normal that my adviser presented my work at a conference while I was there? A couple of month ago, I was in a conference with my adviser. I had a poster and he had a talk. His talk was about my project. In fact, it was newer results that I presented in my poster. After he gave his talk, someone asked me "why while you are here your adviser present your work instead of yourself?"

At that time I basically didn't answer that question and just moved on with a smile. I thought that was not so important but right now, I think is it really ok ? Is it normal among academia? 

Any idea or suggestion is appreciated!
It is normal assuming (a) your advisor is actively involved in the research project, i.e., would be a co-author on any publications coming from the work and (b) your advisor acknowledged your role in the research during his/her presentation. For most faculty advisors (at least in my specific STEM field), much or all of their research is done with advisees, so any research talk they give will likely describe work done with others. 

For reference, my advisor gave a seminar in my own department on a project that I led. I had no problem with this -- it was nice to get their perspective on my work, and they acknowledged that I had done much of the legwork.