“This,” he proudly told me, “is a dwarf or Laron mouse. These mice hold the record for longevity extension in a mammal.” The average mouse has a lifespan of about two years. Laron mice can live for up to five years.

The mouse I held was the equivalent of an 80-year-old human being. Like his genetically engineered relatives, he should live to the equivalent of 120, maybe even 180.

The 5:2 diet: can it help you lose weight and live longer? - Telegraph