When this happens, the thyroid gland is no longer under pituitary control. The amount of hormone it produces is dependent on levels of TSI. TSI are the direct cause of hyperthyroidism in Gravesâ disease and various immune system chemicals known as cytokines also contribute to the symptoms that occur in this disorder.
Confidence votes 20. Female Iguanas will lay eggs when they become sexually mature, which is around 1.5 to 2 years old. They do not need to be fertilized to lay so therefore do not need a male Iguana. They need to be healthy before they lay or else there can be very serious problems.
Iguanas, Sea Lions in Danger. The La Cumbre volcano, situated on uninhabited Fernandina Island, erupted on April 11 for the first time in four years. The volcano's last eruption occurred in May 2005, but Fernandina has more volcanic activity than any other island in the Galapagos, according to The Associated Press. Species such as marine and terrestrial iguanas, sea lions and other fauna are most at risk from the flowing lava.