Green Iguana (Iguana iguana). This tropical lizard can grow to be over 6 feet long, including the tail. It can allow it's tail to break off when grabbed, then it re-grows. They have evolved a white photosensory organ of the top of their heads, often called a 'third eye' or parietal eye. The female will lay about 50 eggs, then leaves them; in this species there is no parental tending of the eggs nor the newly hatched young. Iguanas are threatened by hunting, loss of habitat, and the pet trade.