Animal Weapons The Evolution of Battle by Doug Emlen

Winner of the 2015 Phi Betta Kappa Book Award for Science!


Every animal relies on a weapon of some kind-cats have claws, eagles have talons, even the dogs we keep as pets have a respectable set of teeth. In rare cases, we find species whose weapons have become stunningly outsized, some with tusks so massive that those who wield them look like they should collapse under the weight. In Animal Weapons, biologist Douglas Emlen pulls readers into the worlds of these remarkable beasts, trekking through rainforests and mountain passes to unravel the mysteries of their weapons. Along the way, Emlen shows that the essential biology of animal arms races applies to our own weapons, too. A story that begins with biology becomes the story of all weapons, as Emlen seeks to determine where this parallel leaves us today, in a world filled with the deadliest weapons of all time-nuclear, biological, and chemical weapons of mass destruction.

Doug Emlen Interviews

Doug Emlen interviewed on the SciShow Talk Show with Hank Green

Doug Emlen interviewed on NPR's On Point

Doug Emlen interviewed on Science Friday

Doug Emlen interviewed on Science For the People

Praise for Animal Weapons by Doug Emlen

“A great deal of the living world really is red in tooth and claw. That important principle has needed a real biologist to illustrate and explain it, now accomplished dramatically by Emlen's Animal Weapons: The Evolution of Battle.

—Edward O. Wilson

Pulitzer Prize-winning scientist, Harvard University

“One of our leading evolutionary biologists, Doug Emlen, delves into the deep meaning of entities as different as beetle horns and medieval castles, to take the reader on a joyous ride of discovery about nature and the human experience. Animal Weapons is an authoritative, knowledgeable, and epic narrative of one of the dominant themes of life on earth, including our own. Emlen's curiosity, passion, and storytelling prowess make this magisterial little volume leap from the page.”

—Neil Shubin

author of Your Inner Fish

“This is a great read not only for the stories of conflicts and weaponry in a diversity of animals, but also for the history of human weaponry, and the highly relevant message about arms races the author reads from both.”

—Bernd Heinrich

author of Winter World and Why We Run

Animal Weapons is must read, especially those of us who are interested and concerned about human weapons development. As Douglas Emlen shows definitively, arms races are not something we as a species invented, but instead the most natural thing in the world.”

—Robert L. O’Connell

author of The Ghosts of Cannae and Fierce Patriot

“Doug Emlen has done a superb job of bringing together the stories of animal and human weapons. He makes the biology behind the evolution of weapons understandable for this soldier and engineer, and convincingly illustrates the human animal’s problems in controlling or avoiding catastrophe in the age of weapons of mass destruction.”

—Lieutenant General John Myers

“Emlen’s excellent writing will draw in readers intrigued by astonishingly powerful weapons, both in the wild and in the military, and how they have evolved owing to selective pressures.”

Library Journal

Starred Review

“Absorbing... Throughout the book, Emlen's demonstrations of the many parallels between human and animal weapons are fascinating, even when the possibilities are frightening... Emlen is not a hurried or simplistic storyteller. He is a writer of nuance, and he traveled to many different environments to get the story.”


“Emlen infuses scientific explanations with entertaining anecdotes from his field research at the University of Montana. Each step of the way, he provides parallels with human weapon development and design, from ancient civilizations to weapons of mass destruction, and the evolutionary process of animals. While his conclusions about the human arms race are dire, it is his description of animal weaponry in action and in evolution that will captivate.”

Publishers Weekly

Animals from Animal Weapons by Doug Emlen

Excerpt from Animal Weapons by Doug Emlen


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For as long as I can remember I’ve been obsessed with big weapons, which is rather surprising given that I descend from a long line of Quakers. On field trips to the natural history museum it wasn’t birds or zebras that caught my eye; it was mastodons with curling tusks, or triceratops with five-foot-long horns. In every room, it seemed, loomed another species with a crazy protrusion jutting from its head, or from between the shoulder blades, or from the end of its tail. Gallic moose wielded twelve-foot-wide antlers, and arsinotheres had horns six feet long and a foot wide at the base. I couldn’t peel my eyes from these creatures. Why were their weapons so big?

As I grew and, in particular, as I learned more about biology, I realized that “big” had little to do with absolute size. Extreme weapons were all about proportion. Some of the most magnificent structures are borne by tiny creatures. Hiding in drawer after drawer of dried, pinned specimens in museum archives, for example, are uncountable numbers of oddball species: beetles with front legs so long they have to be folded awkwardly around the animal in order to shut the lid on the case, or horns so big the animals have to be mounted in the drawer sideways. Many species are so small that their weapons become apparent only with a microscope: twisted tusks protruding from the faces of West African wasps, for example, or broad, branched antlers adorning the faces of flies.

I began my career determined to study extreme weapons, so I set out to find the craziest, most bizarre animals that I could. I also wanted my research to take me someplace exotic. In my case, this meant the tropics, so I narrowed my search. My study animals needed to be easy to find in large numbers, to observe in the wild, and to rear in captivity. As fate would have it, the animals that best fit this bill were dung beetles. I resisted at first. After all, dung beetles lack the panache of elk or moose and, well, they eat dung. Dung beetles were also a tough sell whenever I tried to explain what I did to anyone outside of biology. My father-in-law springs to mind—he’s a retired U.S. Air Force colonel—and I’ll never forget breaking it to him that I wanted to take his daughter with me to a remote field station in the thick of a tropical rainforest so I could watch dung beetles.

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About Doug Emlen

Doug Emlen

Laurie Lane Studios

Douglas J. Emlen is the recipient of the Presidential Early Career Award in Science and Engineering from the Office of Science and Technology Policy at the White House, multiple research awards from the National Science Foundation, including their five-year CAREER award, and a Young Investigator Prize and the E. O. Wilson Naturalist Award from the American Society of Naturalists. His research has been featured in outlets including the New York Times and National Public Radio’s Fresh Air. He is a professor at the University of Montana.

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David Tuss

Anne Seliskar

David J. Tuss is a graphic artist who specializes in blending technical accuracy with vivid, lifelike compositions. His work is also featured in textbooks, scientific articles, and technical biology papers. He lives in Helena, Montana, where he works as a wilderness ranger, natural science illustrator, and public school science and art teacher.

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