Turtle Creature

Illustration for a maquette I'll have to make for a Character and Object Design class. Criteria: Creature, think texture, GO!

Description:

This creature lives out its life in the dark, humid climate of the swamp and are typically blind due to low lighting. Their reproduction is much like a normal turtle's and the young are left to fend for themselves once hatched. They typically have to migrate to another swamp. A single swamp typically never has more than three of these giants living there at a time due to food supply. Once large enough, they feed on deer that venture near the edge of the swamp as well as larger fish that live in the water and smaller creatures outside of it. They are born with a seed embedded in their shell and as they grow, so does the tree. These creatures can live to be hundreds of years old if they make it past their younger years. The trees' roots eventually take over the animal's skeletal system and runs through the feet. When they get older they move less, this gives enough time for the roots to embed themselves in the ground, rooting them to the bottom of the swamp. They no longer eat at this point they, absorb nutrients from the ground much like a plant. Over time the animal aspect of the creature dies and all that's left behind are the trees that grew from it.

EDIT: Finally decided to post the illustration with the background, I apologize if it's hard to see on your screen.