Ambush predation releases predators from chasing speed, allowing extreme weapon evolution.

Evidence

Like piranhas, ambush predators no longer chase after prey to hunt them down. In fact, most of them don’t run or swim fast at all. Instead, they lurk motionless, often blending spectacularly with their backgrounds like a hunter in a blind, waiting for prey to come to them. When unlucky edibles happen by, these predators lunge from their hiding places, striking out with a snap of their jaws or a flick of their legs to snatch and incapacitate prey before they even recognize what is happening, much less have time to escape. — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 113 (#expands, via linked claim)

The success of all of these ambush and stalking predators hinges on a quick strike with a weapon that immediately incapacitates its victim. Speed matters, but it’s not the sprint speed of the whole animal that determines the success or failure of these hunts. Instead, it’s the speed of the appendage that matters—how fast it springs out from the body. Here, bigger weapons are almost always better: longer claspers or jaws can reach out farther from the body; bigger appendages can house stronger, thicker skeletal elements incorporating greater elastic recoil and bigger, faster muscles; and hooks or claws at the ends of these appendages move faster the farther they are from a joint or hinge; longer appendages fly through air or water faster than shorter ones. — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 123 (#expands, via linked claim)

In my favorite example, John Christy and his colleagues, including Patricia Backwell and Tsunenori Koga, studied a natural population of the fiddler crab Uca beebei on mudflats along the Pacific coast of Panama. They found that fiddlers were heavily preyed upon by great-tailed grackles, and that these birds had a quirky strategy for catching the crabs. Grackles often employed a “feinting reverse lunge” as they chased a crab. Instead of charging directly at a crab, they would charge to the side of the target crab, seemingly passing it by. As soon as they’d passed, they would whirl and lunge backward in a surprise diagonal feint that often caught the crab unaware. Grackles that did this were twice as effective at catching crabs as birds who simply ran straight at a crab and, remarkably, when birds employed the reverse-feint method, they caught almost exclusively males. Male crabs, by virtue of their distorted major claws, were more conspicuous targets to the lunging bird. The result: in this population, male fiddlers suffered dramatically higher predation than females. — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 306 (#expands, via linked claim)

Categorization

• XREF: connects to: Ambush predators evolve large weapons because they strike rather than chase prey — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 956; Predators evolve counter-tactics that exploit weapon-costly prey — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 306; Ambush predators sacrifice locomotion speed for close-range striking power — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 113 (+4 more)

Related

• Ambush predators depend on appendage speed more than body speed (similarity 0.91)
• Ambush predators evolve large weapons because they strike rather than chase prey (similarity 0.91)
• Ambush predators sacrifice locomotion speed for close-range striking power (similarity 0.91)
• Predators evolve counter-tactics that exploit weapon-costly prey (similarity 0.86)
• Praying mantis ambush hunting explains their spring-loaded raptorial forelegs. (similarity 0.85)
• Smilodon was a heavy ambush predator of lumbering large prey. (similarity 0.83)
• Predator diversity is best explained by weapon adaptation to habitat and prey (similarity 0.82)
• Loss of pursuit hunting drives evolution toward heavier jaws and teeth (similarity 0.81)
• Predation risk is a near-universal cost of elaborate weapons (similarity 0.80)
• Predator weapons stay small because larger ones hinder hunting (similarity 0.80)
• Prey scarcity cycles drive intense selection pressure on predator hunting weapons (similarity 0.79)
• Weapons shrink when predator pressure falls and armor gets costly. (similarity 0.79)
• Releasing soldiers from other tasks lets weapons evolve to extremes (similarity 0.79)
• Wolves evolved dual-purpose teeth and pack tactics to subdue oversized prey (similarity 0.79)
• Competition for reproduction drives evolution of nature’s biggest weapons (similarity 0.78)

Broader Connections

• Ambush predators sacrifice locomotion speed for close-range striking power #expands (0.60) — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 113
• Ambush predators depend on appendage speed more than body speed #expands (0.55) — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 123
• Predators evolve counter-tactics that exploit weapon-costly prey #expands (0.50) — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 306
• Releasing soldiers from other tasks lets weapons evolve to extremes #corroborates (0.45) — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 128
• Prey scarcity cycles drive intense selection pressure on predator hunting weapons #expands (0.35) — Emlen, Douglas J, Animal Weapons_ The Evolution of Battle, 69