Yes, you can auto delete the MassMailer Email Status/Activity History/Email Job Statistics records by going to MassMailer Setup -> Utilities -> Select Schedule or Manual options.
You have an option to auto delete the records that are 30 days, 90 days, 180 days, 365 days older by a recurring scheduled job or one time.
You can also select what types of Email Events you would like to delete such as Open, Click, Bounced etc.,
Following picture shows how to delete by a scheduled job.
Following picture shows how to delete the records manually.