The Marine Iguana

The Marine Iguana (Amblyrhynchus cristatus ) is just one of the many endemic species native to the Galapagos Islands located 1,000km off the coast of Ecuador. The Marine Iguana has adapted over millions of years to become the world’s only marine lizard. These large, distinctive lizards inhabit all 13 of Galapagos’ larger islands (Kutschera and Kleinhans 2013, p.260) with some colonies living adjacent to the residing human population and masses of visiting tourists (Wheeler et al. 2012, p.57). Marine Iguanas live in huge aggregations along the coastlines rocky shores where they are commonly seen basking in the sun during the day (Berger et al. 2007, p.655). These iguanas have lived on the Galapagos archipelago without threat for 5-15 million

The previous absence of predators on Galapagos Islands allowed for physiological and anatomical adaptions throughout species such as flightlesness in cormorants (Radl 2007, p.577). The Marine Iguanas are no exception. For millions of years, they evolved in isolation with no predators (Berger et al. 2007, p.654), the exception being the Galapagos Hawk which only preys on iguana hatchlings and small juveniles during breeding seasons. This equates to a lack of predator recognition. Once predators are introduced, the native wildlife’s ability to escape is almost non-existent. With the increasing human settlements, non-native species such as feral livestock and domestic mammals were introduced. The introduced species exert a strong selection pressure compared to the native life on Galapagos leading to a serious decline and almost complete extinction of some endemic fauna (Hennessy and Mccleary 2011 & Kutschera and Kleinhans

Marine Iguanas show a weak escape response towards attacking predators due to their Corticosterone stress concentrations being unable to rise a sufficient amount in a short period of time causing a delayed response (Radl et al. 2007, Kutschera and Kleinhans 2013 & Berger et al. 2007). Recent studies conducted showed Marine Iguanas predator caution increased with experience when experimenters chased and caught tagged Iguanas over a number of months. Despite the fact researchers found an increase in wariness, their deficiency in long-term behaviour alteration left their response levels too low in order to escape potential dangers (Radl et al. 2007, p.577). It is undocumented whether there behaviour shortcomings are due to slow learning or long-term genetic