Here are some more zoo drawings. They're from this past Monday actually.
Gray prismacolor marker on watercolor paper. This worked out pretty well when I tried it, because I was able to lay the marker on the top of the paper tooth, creating nice rock/tree texture.
The second pic was a study of the rocks at the penguin exhibit. They were real, and interesting. I thought I'd try learning a couple things about the light on them.
The second is an indoor exhibit of real mangrove trees. They're awesome! Like, almost as awesome as banyan trees. This is kind of a strange vignette sketch, but I did run out of time.