Both Nette Londo and Carolyn J. B. Melchert took part in "Ah neen dush" ("Why?" in Ojibwe), a three-year professional development program for Head Start teachers on the White Earth reservation. The program, a collaboration between the White Earth Head Start program and the University of Minnesota, was funded by the Office of Head Start to mentor and support teachers as they developed inquiry-based science and mathematics activities that incorporated Ojibwe language and culture. In this article the authors present the advantages of teaching a culturally based curriculum, and they describe the format they used to develop culturally based inquiry units. They also share two sample units, Londo's ice fishing unit and Melchert's animal tracks unit, to illustrate the types of activities that can be included in a culturally relevant, developmentally appropriate science investigation. (Contains 7 resources and 4 online resources.) [""Animosh" Tracks on the Playground, Minnows in the Sensory Table: Incorporating Cultural Themes to Promote Preschoolers' Critical Thinking in American Indian Head Start Classrooms" was written with Nette Londo, Carolyn J. B. Melchert, Cheryl Gettel, and Jody Bement.]