It realy does depend on the dog . I have just gotton home from a quick fast paced bike ride with Clover (8 year old Rottie x Aussie Cattle Dog) she loved it, and as soon as she was un clipped from the bike at the park she was hooning around flat out along side me . That dog does not act like an 8 year old.

Then on the other hand our 9 year old Penny (JRT x) act as though she is 19 years old . I also know a dog who will be 21 years old this year and still has her crazy puppy moments, she has had her fair share of problems the last 10 years or so but just keeps going.

I will be happy if the BCs live till their grandmothers age of 18 or 19 .