Do the young keep the old, young?

What do you guys think?

It wasn't something I really thought about until my g/f's parents bought a new puppy a while back to compliment their nearly blind and practically deaf 14 year old dog.

I noticed a huge difference in the dog's personality. She became more energetic with the puppy around. Part of it was territory, I'm sure as she didn't like it when the puppy tried to sleep in her spot, but the puppy was constantly nipping at her and trying to play and she grew accustomed to it and took part (as much as she could, anyway).

Then during Christmas, my girlfriend got me, both her brother-in-laws, and her dad passes to play at a paintball course. Her dad, who's in his mid 60's (also a giant), was running and diving all over the place.

i think they do. although i have a friend, maude, who is double my age and she has a lot of energy and keeps me young.