Mobile social games have a knack for attracting highly engaged players, but a new report from analytics firm Flurry reveals that those games can only maintain that high engagement for a finite period of time.

In its in-depth report on user engagement on mobile devices, the group found that users playing mobile social games become very highly engaged within their first few weeks of play, but as Zynga's Draw Something demonstrated earlier this year, those users often quit those games just as quickly as they started.

Flurry found that a user picking up a new social game on mobile will initially play an average of 7.9 times per week, though their attention span and interest in the game will wane over the course of the next few months. On average, only 47 percent of players will stick with a mobile social game after their first 30 days of play, and after 90 days, only 27 percent remain.

Draw Something is a prime example of this rapid user churn, as the game lost millions of users after Zynga acquired the game and developer Omgpop in March.

Luckily, things aren't quite as bleak for single player mobile games, as Flurry noted that an average of 67 percent of users stick with these titles after the first 30 days, and 41 percent remain after 90 days.

Regardless, developers making social or single player games on mobile need to work particularly hard to maintain a large and steady audience within their apps. Their games need to rapidly and constantly acquire new users to offset the inevitable risk of user churn.

Flurry notes that it can be extremely dangerous to put all of your hopes on a single app, and looking at the group's data, it seems wise to spread your audience across multiple titles if possible. After all, you never know if your game will follow in Draw Something's footsteps.