During mating a male literally catches the female and copulates with her. Following copulation, the female flees and finds a spot to dig a nest in which to bury a clutch of up to 25 eggs. On Plaza there are reports that land iguanas occasionally hybridize with marine iguanas . Apparently, male marine iguanas, in a mating frenzy, occasionally attack and rape female land iguanas. The land iguana in the photograph has the most unusual markings I have ever seen, and may very well be a hybrid.
Nobody knows if the hybrids are fertile.
The fact that there is crossbreeding between the two genera of iguanas, Conolophus and Amblyrhynchus , the marine iguana , raises interesting questions about the evolutionary relationship between the two. Some closely related species can hybridize to form viable, fertile offspring, as is the situation among the Darwin Finches . Less closely related species can interbreed, such as horses and donkeys, but their offspring are infertile. It appears that Ctenosaura , the black or spiny-tailed iguana of Central America, is ancestral to both Galapagos iguanas. It has always been assumed that the marine iguana evolved from the land iguana, and there are some data to support that assumption.