He's what I would consider a teenager. Takes two hands to get all the way around his middle, and while sitting on my shoulder his tail is past my belt. I'm unsure about how fast they grow, though. We only have one other iguana and it's been a full adult since she came here.

The ridge is something I'm familiar with in other animals, so thanks for letting me know iggies have them too. I'll look out for them and take a crack at it today.