A simple, fun art activity to do in class is to color. Download and print free wild animal coloring pages from an online source to hand out to your students. The wild animals should be drawn with simple, strong dark lines, and there should not be a lot of background to distract the children. This activity ties in well with a trip to a zoo; for instance, if your class saw flamingos on a field trip, you could hand out coloring pages of flamingos to the students and ask them what the animal's name is, where they saw flamingos (standing in a lake), what color they were (pink) and what they eat (shrimp). Then the students color the animals in to the best of their ability. (Usually, 3-year-olds don't color within the lines, but they will be proud of their artwork nonetheless.)
Another art project you can do with your class is matching wild animal shapes. Use wild animals on the coloring pages as templates for this project. Choose four wild animals that your class has been learning about, and use a photocopy machine to shrink the images to a quarter of their normal size. Cut and paste these four wild animals onto a single sheet of white paper, and make enough copies for your class. Then cut out the same animal shapes from differently colored construction paper (also shrunk to one-quarter size). Cut out enough for your students to have one of each wild animal. Mix the animals together, and have students sort through them until they each have one animal that looks like each picture on their paper. Then they use a glue stick to glue each animal shape onto its outline.
If your class has been learning about wild animals' habitats, make a sticker scene. For example, if your class has been learning about lions, zebras and giraffes, talk about the tall grass and acacia trees of the East African savanna and show them pictures. Then have them draw a wild animal habitat on a piece of white paper to the best of their ability. Once they have scribbled in their brown grass and blue sky, give each child a small pile of animal stickers to place on their pictures. Create a bulletin board of their artwork to show off what the class has learned.