Weapons grow late because development prioritizes mandatory survival expenses first

Evidence

Animals work the same way. They have mandatory expenses that have to be covered first. Energetic demands for basal metabolic functions need to be met: things such as keeping the heart pumping, muscles contracting, digestive tract digesting, and brain thinking. All of these core functions burn calories and use nutrients, exacting a price from the animal, and these expenses are nonnegotiable. Default on them, and the animal dies. Only surpluses of resources—the biological equivalent of discretionary spending—are available for running and fighting, or building big weapons. This is why weapons begin growing so much later than other body parts. Horns, antlers, claws, and tusks all stay small during the course of development, and start getting really big only as males near adulthood—after they’ve already built their bodies—ensuring that mandatory expenses get paid first. Only what’s left over, if there is anything left over, gets shunted into weapons. — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 336

Categorization

• XREF: connects to: States spend on weapons only after mandatory survival costs, like crabs — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 556; Early survival advantages compound into huge adult differences in weapon resources — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 334; Weapons evolve only when reproductive benefits exceed costs — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 199 (+5 more)

Related

• Weapons evolve only when reproductive benefits exceed costs (similarity 0.91)
• Weapon size should track resource availability more than any mandatory body part (similarity 0.89)
• Early survival advantages compound into huge adult differences in weapon resources (similarity 0.89)
• Growing large weapons diverts resources and stunts other body parts (similarity 0.89)
• Arms-race weapon growth makes resource trade-offs drastically impair body functions (similarity 0.87)
• Weapon growth widens the gap between the best- and worst-armed males. (similarity 0.87)
• States spend on weapons only after mandatory survival costs, like crabs (similarity 0.86)
• Bigger weapons usually fail because their costs outweigh their benefits (similarity 0.86)
• Big weapons only benefit males with the reserves to wield them effectively (similarity 0.86)
• Weapons in arms races get so big they impair other bodily functions (similarity 0.86)
• Natural selection usually favors modest weapon size because cost offsets benefit (similarity 0.86)
• Only a minority of males can afford to build full-size weapons (similarity 0.85)
• Reproductive success, not survival, drives the largest animal weapons (similarity 0.85)
• Specific ecological circumstances must align before weapon arms races begin (similarity 0.85)
• Weapon growth is far more resource-sensitive than other body parts (similarity 0.85)

Broader Connections

• Early survival advantages compound into huge adult differences in weapon resources #expands (0.70) — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 334
• Bigger weapons usually fail because their costs outweigh their benefits #corroborates (0.70)
• Weapons evolve only when reproductive benefits exceed costs #corroborates (0.60) — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 199
• Releasing soldiers from other tasks lets weapons evolve to extremes #corroborates (0.60) — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 128
• Natural selection usually favors modest weapon size because cost offsets benefit #corroborates (0.60) — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 21
• Weapon evolution needs both competition and economically defensible resources #qualifies (0.50) — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 191
• Weapon growth is far more resource-sensitive than other body parts #qualifies (0.50) — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 340