Distinctly Montana Magazine

W W W. D I S T I N C T LY M O N TA NA . C O M 21 Another reason is that large nutrient- rich eggs are expensive, and they take time to produce. Depending on the species, females may take days or even weeks to recover from producing one batch of eggs before they are ready to lay another. Males, on the other hand, tend to need only a few minutes. Preparing nests, pregnancy, guarding eggs, and feeding and protecting young all take time. Enter natures's most pervasive and potent form of competition, what Darwin coined "sexual selection." Individuals of one sex compete for access to the other. SNEAKS & CHEATS When only a few dominant males monopolize access to reproduction, there's a strong incentive for the rest of the males to break the rules. You can't win the game the normal way, cheat. Sneaky males are everywhere. Bighorn sheep rams guard harems on sheer slopes high in the Rocky Mountains. e largest and oldest males have by far the biggest horns, and these males consistently win ownership of the harems. Yet, as many as 40% of the lambs end up sired by smaller males. Male sunfish and salmon guard cleared patches of sand where females come to lay eggs. Females chose large, attractive males with the best territories, sidling up next to them so they can shower sperm over her eggs. Tiny males have no chance of defending a territory or being picked by a female, so they dart in sur- reptitiously and squirt clouds of sperm in the mix. Coursers, squirters, satellites and female mimics — there are many ways to cheat. For animals, this means that in addition to traditional confronta- tions with armed rivals, dominant males now face the more insidious threats of male breaking the rules. Similarly, guerrilla forces, land mines, IEDs, and cyberhackers all can undermine the effectiveness of conventional military forces. CASTLES We manufacture our weapons using materials taken from the environ- ment, and these structures exist as separate entities from ourselves — we can throw them away or modify them, if we want to, whereas animals are stuck with the weapons their bodies grow. But animals manufacture structures, too. Termite fortresses, beaver dams, bird nests, spiderwebs, and mouse burrows are all manufactured structures. ey're not part of the bodies of the animals that make them. Today's [human] world is a quagmire of rivalries and factions, ethnic disputes, and religious wars, and the last thing we need is for large and unknowable numbers of these players to be armed with weapons of mass destruction. and Cheats EXTRA NOTES FROM THE BOOK • Elk pay a steep price for their weapons. Bulls double their daily energetic needs and leach essential minerals away from other bones in order to grow antlers. • Cats are agile predators whose weapons are moderate in size, reflecting a balance between selection for killing large prey and selection for agility and speed. • Ambush predators snatch prey with a quick strike from claspers. (Mantisfly). • Dung beetles use horns to tunnel for burrows containing females. • When males fight in unrestricted places, such as in the air, or in chaotic scrambles, agility takes precedence over big weapons. (Cicada killer wasps). • Duels are an essential ingredient of an arms race. When rival males face off one-on-one, selection often favors the male with the bigger weapons, driving evolution of extreme weapons sizes. (Deer, Moose) • Fallow deer and moose pay exorbitantly for their weapons, and for the stamina and energy needed to win fights during the rut, suffering gashes, infections, and depleted energy reserves. Three-quarters of deer bucks die without ever succeeding in defend- ing territories, and 90% fail to mate even once in their lifetime. A bird's castle Bighorn Ram watching over his harem

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