Not so blue, blue iguana

Apparently, blue iguanas aren't always blue. I think...Like green iguanas, as they age they loose their vibrant colors and turn more brownish, gray or even black.
The easiest way to distinguish between the two is their cheeks, spikes, and tail. Blue iguanas have spikes on their cheeks, even, stiff spikes along there back, and no bands on their tail. Green iguanas, on the other hand, have a distinct circle on their cheeks with no spikes, long, uneven pliable spikes along their back, and bands on their tails.