Carne de garrobo is iguana meat, and it comes obviously from iguanas. It's sometimes consumed on the coasts, where iguanas are abundant.
Several farms exist on the coasts, where iguanas are bred and then released. Part of the bred population is used for local consumption, in an attempt to curb hunting of wild iguanas.
Iguana meat, believe it or not, tastes a lot like chicken. When seasoned and grilled, it tastes very much like KFC chicken. Side note: KFC has no relation to iguana meat and what they sell is chicken, don't be getting any funny ideas.