Baby has a dry cough

Does anyone know what this could be? My baby is normal- happy, eating well and everything. For the past week and a half he has had a dry cough. He coughs maybe 6-8 times during the day, but I wouldn't say it is persistent. He might cough twice in 10 minutes and then not again for two hours. He also doesn't cough at night or when he's sleeping.

He doesn't have a fever or anything, so I haven't taken him to the doctor. Does anyone know what it could be? Should I take him to the doctor?