Thought to be a relative of the taxraks, the greops shares a similar repti-mammalian physiology, being a furred egg-layer. Unlike its cousins it is adapted for tree climbing, with its feet having a distinctive arrangement of two toes pointing forward and two backward ('zygodactyl'). Its pelt is orange and spotted to help it blend into its environment. Most striking are the leaf-like sails arranged in double rows down the creature's back. These look like leaves, but are in fact cartilaginous structures that appear to be filled with a symbiotic photosynthetic bacteria that lend a green colouration to the skin. A greops' bite is venomous, delivered through grooved fangs, and whilst not usually fatal to a healthy adult human, is extremely painful. It is thought that the green bacteria play a role in producing this venom.