Younger children will have a lot of fun picking out the mammals from a worksheet with various animals. By printing a sheet with 10 animals of multiple classifications, you can teach children how to separate the different animals into their categories based on visual characteristics. To challenge older students, include animals that could fit into two or more categories. For example, dolphins could be either dolphins or fish based on their physical appearance. The challenge is teaching that, though dolphins look like fish, they are mammals based on the fact that they breathe air.
Teaching older students in elementary school means that you have to come up with more challenging activities to keep them interested in the lesson. When teaching mammalian activities, try having your students come up with a mammal for every letter of the alphabet. It is a challenge when it comes to letters like Q or U. Offer prizes or rewards, like extra credit, to students who can come up with a whole, correct list of "Alphabet Animals" by the end of the class period. For younger students, you can help them by giving mammals for the harder letters. If some animals are included that are not mammals, explain why the animals do not fall into the "mammal" category.
Have students draw pictures of their favorite animals on a sheet of paper. Write the characteristics of mammals on the board, then have each student explain why their favorite animal either is or is not a mammal. Then, have each of them draw a mammal that fits the characteristics. The children will have fun sharing their favorite animals and expressing their creativity to their classmates. Have older students make models of their favorite mammals out of other materials for homework. Give them three weeks to do their projects and give prizes for the most creative.
Another fun way to teach children about mammals is to give out a word search containing the characteristics that make an animal a mammal. For older students, give out highlighters and have them highlight the letters that make up the words. Include words that describe mammals, animals that are mammals and, for an extra challenge, the names for mammal babies. For example, you could include "fur," "cat," and "kit" (a baby fox) in your word search. Have students identify which adult animal name matches with each baby animal name.