Some assumptions about biology are so deeply rooted in our thinking that they seem beyond question. These concepts - expressed in playful jargon - are our sacred bovines. With a light-hearted spirit, Douglas Allchin sets out to challenge many of these common beliefs about science and life. Allchin draws on fascinating insights from science to illustrate the ironies in many widespread beliefs. Be prepared to challenge the notion that male and female are fixed natural categories. Or that evolution implies cutthroat competition in human society. Or that we struggle against a fundamental immoral nature. Or that genes establish our identity. Or that science progresses through rare leaps of genius. Or that politics and emotions inevitably taint good science. Sacred Bovines revels in revelations about the nature of science. Reflecting on the many errors in commonly accepted, everyday ideas also fosters creative thinking. How do we challenge assumptions? How do we think outside the box? The many examples here provide inspiration and guidance, further elaborated in a retrospective epilogue. An additional Afterword for Teachers highlights how the essays can foster learning about the nature of science and describes some practical classroom strategies.