Emlen described his work with dung beetles and how the above-described perquisites can cause the development of extreme weapons in part of the species.
Some dung beetles roll dung into balls and have to deal with scrambles with other dung beetles to protect their food source. Other dung beetles that live in the same habitat and have the same available resources take dung down to the bottom of a tunnel they have dug. These tunnel-digging dung beetles have developed horns.
Emlen said dung beetles that dig tunnels must protect their food source from beetles who try and go down the tunnel, creating a one-on-one fight. In a duel, extreme weapons are an asset.
“One simple change in how they get and hide their food resource changed their weaponry,” Emlen said, adding that the same set of conditions set off arms races in the human species.
“Changes in technology aligned male fights, so they met in duels and weapons became extreme,” he said.
Emlen described the development of closeable gun ports on ships and how such technology forced battles to be fought in close range, one-on-one, and gave bigger ships the advantage. Ships became longer and were built to hold more than one row of cannons, Emlen said.
“Just like the dung beetles, changes in human technology aligns with face-to-face duels,” he said.
Extreme weapons also may serve as signals or deterrents, Emlen said. With animal species, bigger weapons serve as a proxy for fighting ability and deter duels.
He said there is a paradox of peace related to extreme weapons, and extreme weapons have acted as deterrents in human controversies, as well, such as the Cold War. Emlen said he believes there still is much to be learned from the development of extreme weapons in animal species.