This week, I took Fifi to a vet appointment at a new clinic, after her old doctor moved to Boston. During the exam, the vet tech pointed out Fifi’s delicate features and unique characteristics. After consulting with the actual vet, they decided that its definately possible that Fifi is a hybrid iguana. Part Common Green Iguana, part endangered Grand Cayman Blue Iguana. Apparently there is a breeding facility in the US that breeds the Caymans with Green Iguanas to try and preserve some of the Cayman genes.
Among other differences, Green iguanas have spikey dewlaps, while Blue iguanas do not. Blue iguanas have flatter/pointier heads, while green iguanas have boxier heads and can have horn-like scales on their noses.
Here is a comparison:
Green Iguana
Grand Cayman Blue Iguana
And here is our Fifi:
Who knows if she is or isn’t, but it’s certainly interesting to think about. And now she really has something that could set her apart from all of those other 3 legged Green Iguanas out there. 
Two things:
1. Just with your pictures, I thought Fifi looked like an interesting cross between the two…but then when I went to the Blue Iguana Recovery Program website, the one on their main page looked a lot like Fifi!
2. On the site above, they have an interesting product you may want to look into:
http://www.blueiguana.ky/bobblehead.htm
Huh. Fifi definitely looks like some sort of hybrid. She’s too cute to be a common iggie!
The bobble head iggy is pretty fantastic!