Melatonin experiments

Factual Questions
1

Some time back in the early 90s, it was reported that giving melatonin to lab animals (both mice and rats, I believe) will extend their lifespans by about 25%. Now mice and rats typically live for about 2 or 3 years, which are not especially long lifespans. Has anyone reported any results on experiments with longer-lived animals?

2

here

here

here

here

and this

Make of it what you will. Looks like the jury is still out. Nothing conclusive.

3

Thanks for the links Chao, but none of them reported any experiments on any animal other than mice, at least that I could find. Well, except for the first which was about the effects of melatonin on drosophila melanogaster. However, I doubt that fruit flies live longer than mice.

Anyone else know of any other experiments?