"was eaten" vs. "has been eaten"

Question

1. It was eaten by a tiger.
2. It's been eaten by a tiger.

Do these basically mean the same thing? Can they be used interchangeably?

Answer 1

The distinction Lucian Sava has correctly made may become clearer if we talk about hats instead of tigers.

Remember that old wool hat I had? It was rain-repellent and had a wide brim.
-- It was thrown into the trash when we moved from the apartment to the house back in 1998.

Have you seen my old wool hat?
--It has been thrown into the trash. I hope you weren't thinking of wearing it.

The present perfect (passive) in the second example expresses the idea that the event which happened in the recent past has potential relevance to the present moment. The hat went into the trash quite recently.

Answer 2

1. It was eaten by a tiger.

2. It's been eaten by a tiger.

Has been eaten is a present perfect passive tense which should be used at an unspecified time in the past. Consequently, don't use this tense when the time is specified, use simple past instead.

So in your question context, as no time is specified you may use either #1 or #2.

Obviously a distinction should be made:

Present simple implies a finished action in the past whereas, present perfect implies an action started in the past an continuing up to the present or having effects in the present.