User blog comment:Xilinoc/Realistic One Piece/@comment-24769684-20150525202904/@comment-10543621-20150527001202

Actually, I see it more like eating the fruit allows you to gain the positive properties of that animal, but it doesn't abolish your own innate properties.

Kinda like how all other Zoan users can return to their normal forms and walk like a normal human as much as they want. They just gain the 'abilities' so to speak, of the animals. Like for mystical zoans like Marco, he gained all the abilities of a phoenix without losing anything human.

In the case of the hito, I guess one of the 'abilities' of a human would be their life-span, along with human intellegence and speech. Chopper doesn't lose his reindeer 'abilities' in anyway. He still understand animals (although that's just manga logic, that animals all understand each other), and he's still resistant to the cold.

In the case of having the lifespan of an animal, I think that would apply to the inanimate objects that come alive after consuming a Zoan. I'd expect the lifespan granted to those objects to match the animal of their fruit.