In search of the Peru Pacific Iguana

The Peru Pacific Iguana (Microlophus peruvianus) is an endemic lizard from Peru, Ecuador and Chile. They are big lizards with sexual dimorphism in size (98 mm male, 78 mm female) and colour. In Ecuador, they are distributed on the western coasts of Guayas and Santa Elena provinces. To study the effect of sympatry on their behaviour and ecology, we visited two allopatric locations (Ancon and Chanduy). Ancon is a small oil fishing port on the west coast of Ecuador; it has a beach that sits on a cliff full of rocks without vegetation.

Ancon beach habitat characterized by the presence of cliffs and rocks. A small population of
M. preuvianus were find here (around 4 males and 12 females).

While Chanduy is a small town beach with a rock wall dividing the town from the beach. In Chanduy, we also found a small population of the Pacific Iguana (M. occipitalis) limited to the houses boundaries.

Chanduy beach habitat where we find a large rock wall, which is the perfect habitat for M. peruvianus.

Image gallery from Ancon and Chanduy beaches

We also visited two sympatric locations (El Pelado and La Chocolatera). The La Chocolatera locality, part of La Puntilla de Santa Elena reserve, has several types of habitats and supports both species.

These rocky cliffs are suitable for M. peruvianus.

The La Chocolatera vegetation formed by small shrubs and creeping plants is suitable for M. occipitalis.

Image gallery from La Chocolatera

In all localities, the Peru Pacific Iguanas were found mainly on the rocks, walls and trunks. The aim of this first field trip was to study the influence of sympatry on the behaviour and ecology of this species. We measured population density in each locality, and took note of several behaviours like territorial displays (head bobs, push-ups, tail movement and attack), mating displays (head bobs, neck bite, and copulation), eating, basking etc. Additionally, male territorial displays were filmed, and morphological data of almost 25 individuals were obtained, which often required us to climb the cliff and run on the rocks to observe them. The research effort more than met our requirements for the first fieldwork season.