Galapagos Tortoises

Here's a two minute video of some tortoises. Don't blink or you may miss some of the action!!

Land Iguanas

Ah, now these big boys are Lizards! Land iguanas can get as large as one meter long and weigh as much as 13 kg. The marine iguanas may be specialized for an ocean going lifestyle, but for some reason these lizards capture my interest more. Look at the scale patterns on the faces of the males in the photos below. I think they are just beautiful.


In the photo below you can see the marked sexual dimorphism between the male and females. The female is darker and smaller than the male.
There are two species of land iguanas endemic to the Galapagos. One species ( Conolophus pallidus) is only found on the island of Santa Fe, and the other, ( Conolophus subcristatus), is more widespread.

The adults eat the cactus pads of the Opuntia cactus, and juveniles eat insects, and even finch nestlings. The normal lifespan for these iguanas is over 60 years.

When Darwin arrived in 1835 he remarked that he had trouble pitching a tent because there were so many iguana burrows. Unfortunately, this is no longer the case. There may be as many as 10,000 individuals of C. subcristatus left in the Galapagos. Introduced animals such as cats, dogs, rats, and pigs along with human activity have taken a toll on these large lizards.

Marine Iguanas

An odd condition on the Galapagos is that reptiles are more common than mammals. This is not the case in most areas of the world. The ancestors of the reptiles found today on the Galapagos were hardy enough to make it across 600 miles of ocean from the South American mainland aboard rafts of vegetation. Mammals and amphibians for the most part did not survive such direct exposure to the sun, and could not survive as reptiles did, with out water for weeks on end.

Perhaps the ancestor of the land and marine iguanas was similar to this green iguana found in Ecuador.


Marine iguanas forage on red and green algae. Young iguanas and females don’t venture too far off the rocky coast, but males can forage to depths of 10 meters. Being ectotherms they walk a tight rope between feeding the in cold water and staying warm enough to actively feed and digest their algae salads. The body temperature of the male iguanas can drop as much as 10 degrees Celsius while they are foraging. They are much larger than the females, with some males weighing as much as 10kg.



The animals I saw spent a great deal of time basking in the sun. The young iguanas like those below clustered in areas away from the adults.


These iguanas are the only ones in the world who forage in the ocean, and as you can imagine they consume a great deal of salt in their diet. To rid their bodies of this salt they blow it out their nose from salt glands behind their eyes. They have the most efficient salt glad of any reptile, but I wouldn’t be surprised if the salt gland found in ocean going birds was more advanced. :) Take a look at the nostrils of the iguana in the photo below. The slight tube shape helps them expel the salt. The sneezing noise they make as they excrete salt is the only noise these lizards make.


Their dark color helps them absorb heat, and is great camouflage. There are numerous marine iguanas in the photo below. How many do you see?


El Nino events can raise the water temperature from a normal temperature of 18 to 32 degrees Celsius. This kills the algae upon which these iguanas feed, and can cause their populations to crash. During times of extreme starvation these animals can reabsorb bone and actually shrink in size to survive.