ANIMAL WEAPONS :: Douglas J. Emlen

If you are any kind science and nature nerd and have a minutia of interest in how such influences as mating, territory, and predation impact how animal forms evolve (sometimes even in one direction and back again), stop reading and just go get Animal Weapons: The Evolution of Battle. If you need a little convincing, read on, I welcome the challenge.

Animal Weapons is the most geeked-out fun I’ve had reading in a long time. Author Douglas Emlen has brilliantly laid out all kinds of super cool, sciencey principles in a manner that’s engaging and easy to understand. Animal Weapons kept me as engrossed as a top-notch thriller.  I was grinning from ear to ear from the time I read this early synopsis to the end:

This is a book about extreme weapons, structures so gargantuan and bizarre they look like they shouldn’t be possible—so awkward that the animals who bear them ought to tip over, or trip, or get tangled each time they attempt to move. Why are these weapons so big? And is there such a thing as too big? To answer these questions, we’ll delve into the murky forests and mountainsides where animals do battle, immersing ourselves in the details of their lives in order to identify patterns: things these wildly different species all share in common, and things that illuminate the logic behind such extraordinary animal forms. 

Of the estimated 3.1 million known species, only about 3,000 wield an extreme weapon of some sort – from tusks and horns to crazy protrusions from the head or shoulder blades. While sizes range from the ginormous (16’ Mastodon tusks) to the miniscule (1/4” fly antlers), all weapons are relative to the size of the animal. Growing weapons consumes valuable resources, so animals only enter an arms race when certain factors dictate.

What factors could have such an impact, you ask? The basic equation illustrated in Animal Weapons is this: sexual selection (i.e., the women get to let the men fight over them) + economic defensibility (a need to secure territory for breeding, grazing, etc…) = extreme weapons. Those elements and many more are dissected in captivating detail in each chapter, with real-life examples. Here’s a brief look at one to whet your appetite:

A particular beetle has to guard a tunnel where the female he wants to mate with resides. Because he has to compete with other males for that tunnel and the affections of Mrs. Beetlicious, evolution has provided him with some substantial horns to use as weapons. Not all the beetle dudes are blessed with horns as big (or even any horns at all). So the under-endowed beetles often become “sneaks.” These sneaky bastards make their own tunnel not far from well-endowed beetle’s and then tunnel SIDEWAYS into macho man’s castle to mate with his lady on the sly. How super cool is that? (For beetles. Human dudes? Not cool at all.)

But it gets even better. Nature will tolerate a certain percentage of procreation by sneaks. But if the sneaks start to have too much success, the extreme weapon, in this case the beetle’s horns, may be deemed unnecessary (no need to guard the female if the sneaks are getting so much of the action anyway), and not worth the resources the beetle requires to grow and sustain them. Therefore, the horns may begin to evolve back out of the species. HOW AWESOME IS THAT?

But wait, it gets awesomer (not a word, don’t care). Turns out, very similar principles apply to the human arms race. Emlen provides human-specific examples of the animal-world principles discussed in most chapters, and it’s unreal to see how they apply. The entire structure of the Royal Navy evolved along these same principles. When sneaks (German U-boats) began attacking cumbersome battleships, those battleships evolved into aircraft carriers.

If this book is making me sound like a 6-year-old who just opened the dog breed picture book that was all she wanted for Christmas, then my enthusiasm is being properly expressed. The only part that didn't have me completely riveted were the few sections at the end dealing entirely with the arms race of mankind. I just don’t find us or our (modern) military as interesting as the animal world, and while I thought the analogies in the animal chapters were super, the military-only sections just weren't as smack in the middle of my wheelhouse.

STREET SENSE: It’s only February, but I’d be shocked if Animal Weapons isn't in my top ten reads of 2015. Top 5 isn't even a stretch, it was that fantastic. I can’t recommend it highly enough if you’re at all interested in the animal world and/or principles of evolution.

A FAVORITE PASSAGE: I must have been distracted, because I never noticed the blade sliding across my thumb until it was too late--I’d sliced clean through to the bone. We were miles away from civilization with no easy way to get to a hospital. So we sterilized the wound with rum and sutured it with ants.

(Yes, you read that right, SUTURED IT WITH ANTS. To get the whole story, you’ll just have to read the book.)

COVER NERD SAYS: A great drawing of a saber-toothed cat on a book about animal weapon evolution? I ordered this book based on the cover and title alone. Although I was a bit concerned about the knight on the cover, the image was small enough I figured the book concentrated on the weapons of animals and not those of men. The proportions turned out to be pretty right on, so I think the cover served the book (and the reader) exceptionally well. (The analogies to knights and their armor were stellar, by the way.)  I love this cover.