What is a Furry (second life) avatar?

I saw this on a site "Luskwood Creatures" and its $950.. But what exactly is it? Link: https://marketplace.secondlife.com/p/Luskwood-Sky-Blue-Wolf-Furry-Avatar-Male/983304?id=983304&page=1&slug=Luskwood-Sky-Blue-Wolf-Furry-Avatar-Male