 Wild adult green iguanas have been observed eating birds' eggs.Zoologists, such as Adam Britton, believe that such a diet containing protein is unhealthy for the animal's digestive system, resulting in severe long-term health damage, including kidney failure and leading to premature death.On the other side of the argument is that green iguanas at the Miami Seaquarium in Key Biscayne, Florida, have been observed eating dead fish and individuals kept in captivity have been known to eat mice without any ill effects.