Review: The Wild Life of Our Bodies

 The Wild Life of Our Bodies is a book about the relationship between our bodies and their evolutionary partners/predators/symbiotes that modern life has changed. It is surprisingly wide ranging, from discussing various diseases (such as Crohn's disease) that have symptoms largely alleviated when some patients deliberately infect themselves with various parasitic worms in their intestines. In fact, one postulate in the book (not backed up with evidence) is that the modern epidemic of obesity is because historically humans have always had tapeworms and other parasites in their bodies absorbing nutrition that are no longer widespread in developed countries, and now that those parasites are no longer in our bodies our super efficient metabolism now causes obesity.

There's one particularly keen observation about lactose intolerance and how few people (globally) actually have the gene that allows them to process milk as adults, yet the USDA food pyramid encourages consumption of dairy products:

That our bodies respond differently to the same food as a consequence of our ancestry may seem obvious. Yet we ignore such realities every day. The USDA food pyramid still has as one of its main items “milk,” along with fruits, vegetables, meats, and beans, even though most humans worldwide cannot digest milk. Milk is just the beginning of the unraveling of the idea that any one species of plant or animal food (or processed version thereof) might do us all good. (pg 132)

There's a discussion of why we have a natural, instinctual aversion to snakes, and why we ended up as being the only hairless ape. (body lice and ticks are a major reason, and in fact we can stop the spread of headlice in schools if we could get all parents to get their kids' heads shaved!)

Rats, pigeons, cows, antelope, and monkeys groom. When pigeons are prevented from grooming, they grow speckled with lice. Cows prevented from cleaning themselves have four times as many ticks and six times as many lice as those left unhindered. Antelope have a specialized tooth called a “dental comb” that seems to serve no purpose other than to aid in grooming away ectoparasites (evidence of yet another case in which ectoparasites seem to have posed a cost that was significant enough to cause animal bodies to evolve).4 Many animals groom themselves and each other even though the lost time such efforts entail is costly. (pg. 220)

The book ends with the observations that urban infestations (cockroaches, rats, pigeons and other undesirable weeds) are a reflection of the ancient human predilection for living in caves. That those creatures fare best in caves is also why they fare best in cities. I'm not sure I 100% buy his argument, since plants like dandelions also do well in cities but I've yet to find a dandelion in a cave. Similarly bats do well in caves but we rarely see them in cities.

Nevertheless, this book gives you lots to think about and is worth a read.