Posts Tagged ‘iguana’

I have some conflicting information about our mystery iguana.  It is an iguana from the Galapagos, but I found it looking for photos of hybrid iguanas.

According the site that this image came from, this iguana is a hybrid between a marine iguana and a Galapagos land iguana.

The commentators on this reptile forum disagree. It is nothing more than a juvenile marine iguana.

Such hybrids are known to exist. They have been well-documented on South Plaza Island, where the feeding ranges of the two species overlap. The two species interact more when El Niño forces the marine iguanas to forage inland– something they are very poorly adapted to do.

I remember seeing a hybrid from South Plaza on the Jeff Corwin Experience several years ago. Jeff Corwin sort of hyped it as a new evolutionary lineage for Galapagos iguanas. Unfortunately, the hybrids are sterile and are evolutionary dead ends.  They lead to nothing new.

The reason why El Niño forces marine iguanas out of their normal habitat is because the warm water associated with the phenomenon causes red algae to grow very well. It out-competes the green algae that the marine iguanas have evolved to eat.

To survive El Niño, Marine iguanas have another interesting adaptation: They shrink. The smaller size allows the to better utilize the more finite food resources. Smaller iguanas don’t need as much food. When the El Niño passes and the green algae returns to its normal lushness, the marine iguanas return to their normal size.

Not a bad adaptation.







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Marine Iguanas

An iguana that goes into very cold ocean water to eat seaweed.

That’s got to be one of the strangest things to have ever evolved.


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