Chances are most of us don’t give much thought to what it means to be a mammal. In science class we learn that mammals are warmblooded and give birth to live young. But it is much more complicated than that, as writer and former neurobiologist Liam Drew explains in his fascinating debut, I, Mammal.
As a scientist, Drew had a good working knowledge of mammals and their evolution. But becoming a father changed his perspective. The natural human processes of pregnancy, childbirth and breastfeeding piqued his curiosity regarding the specific traits that make us mammals. As he notes, “For twenty years, I’d studied biology; finally, I understood that I was biology.”
Each chapter is devoted to a specific aspect of mammalian biology, such as X and Y chromosomes, the reproductive process and the calories we need to support our warmblooded lifestyle (up to 20 times more than our coldblooded cousins). He explains how mammals are divided into three groups: the monotremes, marsupials and placental animals. Some of the facts are mind-boggling: Placental animals (yes, that includes us) make up the overwhelming majority of the three types, with 5,080 species to be exact, 2,277 of which are rodents.
Although mammals share many commonalities, there are vast differences, too, demonstrating the delicate balance between survival and extinction. Drew explains these in detail, such as the painstaking, dangerous journey marsupial infants must take to reach their mother’s mammary glands. It is amazing just how long it took scientists to understand many mammalian functions and how many theories are still being debated. Drew discusses these various hypotheses, often pointing out those he feels carry the most weight.
Skillfully weaving scientific fact with beautiful prose and humor, I, Mammal is a compelling narrative for anyone who wants to discover more about what makes us tick.
