When preschoolers first begin to discover that animals are alike in some ways and different in others, they may ask a lot of questions. As a large group activity, discuss the different characteristics of many different kinds of animals. For example, birds have wings, lay eggs and can fly while mammals have hair or fur and give birth to their young. Compare and contrast as many animals as children are interested in learning about. In a large group, have children suggest two animals to compare. Create a written list of all of the things that are similar and different about the two animals.
Use magazines to find as many pictures of animals as you can. Give each child a pair of safety scissors, and ask them to cut out any pictures of animals they can find in the magazines. Since preschoolers are still fine-tuning their cutting abilities, ask them to cut a big circle around the animals they find in the magazines. For a bit more durability, you can glue these pictures onto construction paper or posterboard and cut them out again. Since the pictures will be used for other activities, they will need to stand up to multiple handlings. Store the animal pictures in a large envelope or a basket.
Using the pictures the children cut out, play a simple classification game. Find two pictures, one of the ocean and one of a open field or a farm, and create two categories: "Ocean Animal" and "Not an Ocean Animal." Invite children one at a time to choose an animal card and decide whether it is an ocean animal or not. You can use two baskets to categorize your animal pictures, one with the ocean picture attached and the other with the land picture attached. Remember to discuss the characteristics of ocean dwelling animals while children are deciding into which category to classify the picture. This is a beginning classification activity for young preschoolers.
When children have become adept at classifying animals using only two parameters, it is time to present more of a challenge. This activity works best with a small group of three to four children. Use the animal pictures the children cut out again for this activity. Lay all the pictures on the floor so that children can see them all. Give the children an animal characteristic, such as "I have feathers," and ask them to find all of the animals in the bunch that they can classify with this characteristic. For even more of a challenge, give children two characteristics to match to the animals, such as "I have fur and four legs."