This is because stories were traditionally told using the past tense. This made the narrator sound as if they were narrating events from a distance, instead of being 'present' amongst the action.
The past tense is used for things that have already happened. He was sticky. The present tense is used when something is happening now or when something happens regularly. He is sticky.
The abstract is usually in the past tense due to it showing what has already been studied. Example: “This study was conducted at the Iyarina Field School, and within the indigenous Waorani community ...
The usual practice is to have the present tense express a current event while the past tense indicates the past. But there is a dramatic situation the present tense can state a past occurrence too.
When two things occurred in the past, the past perfect tense comes in handy to express them within a clause. In other words, unlike the present perfect tense which states an action that started in ...