The hybrid iguana is a first generation hybrid, the result of intergeneric breeding between a male marine iguana (genus Amblyrhynchus) and a female land iguana (genus Conolophus) on South Plaza Island in the Galapagos Islands where the territories of the two species overlap.
They are dark with white speckles or bands of mottling near the head. (Marine iguanas are solid black, while land iguanas are reddish-yellow.)
The first hybrid iguana was discovered in 1981. In 1997, high ocean temperatures during a severe El Niño season caused failure of the seaweed beds around the Galapagos Islands and about half the marine iguanas starved to death. Others searched inland for plants to eat. They also mated with the land iguanas, which produced an unusual number of hybrid iguanas. As of 2003, twenty had been found. DNA testing by a German researcher revealed that marine iguanas were the fathers and land iguanas the mothers.
Anatomy and morphology
Marine iguanas have sharp claws and are able to grip rock under seawater and eat seaweed, whereas land iguanas lack sharp claws making them unable to climb on the cacti which are their staple foods. Due to decreased quantities of seaweed, marine iguanas will often seek food on the land, taking over the food source from the colonies of land iguanas.
Hybrid iguanas have sharp claws and can climb on cacti and also eat seaweed underwater. It is held that the hybrid iguana can survive in both sea and land environments. Despite their long separation time and there being two distinct species from different genera, the offspring are viable, although likely sterile. The hybrid iguanas have a laterally compressed tail like that of the marine iguanas, but they have not been seen swimming. They also have sharp claws like their marine fathers, which enable them to climb for food rather than waiting for it to drop from a cactus as the land iguanas do.
- Galapagos: Evolution at the Speed of Life. NHK (DVD). Wild Secrets: Worldwide Ecosystems. Produced by Hiromichi Iwasaki, Hiroyuki Wakamatsu, Yasuhiro Koyama, Yoshiyuki Ohki. 2003.
- Source: Commemorating special TV program titled "地球危機2008" (Global crisis 2008) by TV Asahi, on 50th anniversary, on Jan. 4, 2008.
-  TV Asahi program "素敵な宇宙船地球号" ("The earth", A Wonderful Vessel in the Universe) 2007 May 6
- Rassmann, Kornelia; Markmann, Melanie; Trillmich, Fritz; Tautz, Diethard (2004), "Tracing the Evolution of the Galapagos Iguanas", Iguanas: Biology and Conservation, California: University of California Press, pp. 71–83, ISBN 978-0-520-23854-1