Costa Rican Black Iguana Peeping from Inside the Trunk of a Tree

I took this photo in Costa Rica while I was visiting the Manuel Antonio wild life reserve in Kepos near the coast of Costa Rica. While walking down a trail you can see many of these large iguanas and they seem to have no fear of beeing around humans unless you get too close. I spotted this one inside a trunk of a tree. all I wonder is how he got inside.