Through some random Internet searching I discovered that that's the equivalent of a 75-year-old human.
Due to the cataracts that developed this year, he may have lost sight in one eye and have limited vision in the other, but he's still very active and enjoying bounding around his large home and run.
Whenever he goes for check-ups, vaccinations etc, the vet always comments on Barney's good health.
The old trouper has certainly shaken off his surly, teenage, moods - from when we were in our previous home and he would just sit in the middle of his run and glare at us.
No doubt due to age and acceptance of his condition, he's much friendlier these days and enjoys a good scritch behind the ears or a stroke of his luxurious fur.
For his birthday, Rachel got him a cake of seeds and grasses, which he tucked into the moment I put it in his hutch.
I've also got him a new tunnel, but that's arriving later today. This too will be coated in seeds as he loves to strip the edible covering from his tunnels, until eventually just the bare cardboard is left.
And then he starts to shred that as well.
|Barney's birthday seed cake|