Since becoming a first-time mum last summer, I’ve become painfully more aware of the sexually-based differences between myself and my husband as we navigate the new-to-us territory of parenthood. (How can men listen to a baby wail for so long without doing anything?! And why do I feel I traded my career for motherhood, while his career is taking off and he gets to be an awesome dad?!) Yet, no matter how baffling these differences feel to me, they are negligible compared to the ones explored in Odd Couples: Extraordinary Differences Between the Sexes in the Animal Kingdom (Princeton University Press, 2013).
Odd Couples is a refreshingly informative and passionate jaunt through the extreme differences found in the sexes of eight different animal species. Evolutionary biologist Daphne Fairbairn infuses her rigorously researched text with elegant and poised language, a pervasive sense of insatiable curiosity, first-hand experiential scenes and learned suppositions. The result is a feeling of listening, enthralled, to the best lecturer in far-and-away the best college biology course you ever experienced.
Fairbairn begins the book with a standard introduction revealing biographical information which exemplifies her expertise in evolutionary biology. She shares that the roots of her questions about sexual differences stretches back to her early-career field studies on wild deer mice. The main questions her book explores are “why sexual differences are such a pervasive and significant part of the fabric of animal variation and, in particular, why males and females have come to differ to truly extraordinary degrees in some animal lineages.”
The author then explains why she chose the eight particular species profiled in the book: elephant seals, great bustards, shell-carrying cichlids, yellow garden spiders, blanket octopuses, giant seadevils, bone-eating worms, and shell-burrowing barnacles. Her choices span vertebrates and invertebrates; mammals, birds, fishes, mollusks, and worms; terrestrial and aquatic species. They span examples where males defend large harems of females which are closely aggregated in space for a short time of each year; but also species where males must search out sparsely distributed and rare females; species where males weigh seven to eight times more than females, and species where females are 40,000 times heavier than their dwarf male counterparts; even species where males appear to have been reduced to nothing more than sperm-producing parasites!
What makes this book work is that Fairbairn is never overbearing with her extensive encyclopedic knowledge. Rather, she skillfully dispenses it with such enthusiasm that the reader is infected with her curiosity to know why and how such extreme differences between sexes of the same species came to be.
My favorite chapter was the one on elephant seals. Fairbairn began by recounting a chance personal observance of a rookery during mating season. The sense of awe and wonder that she conveyed in this scene set the tone for the entire book, where she deftly examines the life cycles of each sex of species, foraging and reproductive strategies of the adults as well as brooding strategies and dispersal of the young.
Odd Couples includes a glossary, seventeen color illustrations, numerous tables and figures and a concluding chapter summarizing the diversity of sexual selection. This is a book that professional biologists will find to be a valuable reference, while lay readers will find it to be a densely informative but highly engaging read. While at times the reading may be a little technical for a lay reader, Faribairn manages to fill her book with the perfect doses of knowledge and passion. Her love for the subject matter kept me turning the pages, all the way to the last.