Mating competition kills off most males before they ever reproduce.

Evidence

Not all males fared equally. In fact, in terms of reproductive success, an overwhelming majority of them failed miserably. Three-quarters of the males died before they were large enough—armed heavily enough—to succeed in guarding a territory, and 90 percent of the males never managed to mate with a female even once in their lifetime. Of the males who did reach critical size and rank, most suffered catastrophic losses to their body condition as they battled for their tiny pieces of real estate, accumulating stress, slashes, parasites, and pathogens as they locked in battle after battle for territories that the females often ignored anyway. — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 314

Categorization

• XREF: Parallels human data on reproductive skew in polygynous societies; connects to evolutionary psychology literature on male competition. — connects to: Male combat for mating access frequently causes serious wounds and sometimes death; Monopolized reproduction drives males of many species to cheat — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 407

Related

• Monopolized reproduction drives males of many species to cheat (similarity 0.90)
• Male combat for mating access frequently causes serious wounds and sometimes death (similarity 0.89)
• Males that assess rivals before fighting survive and reproduce better. (similarity 0.82)
• Cheating males erode the reproductive payoff of weapons, capping their evolution (similarity 0.81)
• Extreme skew in mating success drives arms-race escalation in weaponry (similarity 0.81)
• Excess rival males over scarce fertile females drove knightly combat in medieval Europe (similarity 0.81)
• Younger noble sons could only marry rare heiresses, intensifying mate competition (similarity 0.80)
• Male aggression is primary and explains competition, not vice versa. (similarity 0.78)
• Sexual selection can be far stronger than natural selection and drives weapon extremes (similarity 0.78)

Broader Connections

• Monopolized reproduction drives males of many species to cheat #corroborates (0.50) — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 407