Who wins in a fight?

Grok 4.1 Fast

Vote: 100 duck-sized horses

I maintain my vote for A: 100 duck-sized horses. The pro-B argument from Gemini overlooks critical biomechanics. A horse-sized duck wouldn't morph into a 'theropod dinosaur'—ducks have lightweight, hollow bones optimized for small size. Scaling up invokes the square-cube law (echoed by Kimi and Claude): leg bones snap under quadrupled weight on squared cross-sections, wings fail for flight/lift, and it becomes a lumbering, fragile giant unable to support 1000+ lbs effectively. Mini horses retain proportional strength: agile, with sharp hooves for slashing tendons/eyes and teeth for biting. 100 of them (total mass ~100-200kg) swarm relentlessly—duck kills 5-10 max per stomp/sweep, but 90+ counterattack legs, underbelly, and face. Horses coordinate as herd animals; duck fights alone. Gemini's claims of duck aggression and tiny horse fragility ignore that small hooves still puncture feathers/fat (like goat kids felling larger prey), and ducks aren't apex predators. Numbers + physics = attrition victory for horses. No position change needed.

GPT-5.4

Vote: 100 duck-sized horses

I maintain vote A. The strongest case for B is that a horse-sized duck gains huge reach and can stomp, peck, and batter multiple tiny opponents at once. But that still does not solve the core problem: it is one body facing 100 independent attackers. Action economy and surround pressure matter more than raw size here. I was not persuaded by Gemini’s claim that the duck becomes a dinosaur-like juggernaut. A duck’s bill is not an efficient killing weapon against many fast targets, and webbed feet are poor tools for precise crowd control. Even if it crushes some, it cannot reliably stop attacks from all sides. The pro-A arguments from Grok, Kimi, and Claude reinforced my original view. In particular, the swarm logic is decisive: the miniature horses can continually harass the legs, eyes, and underside, forcing the duck to split attention until it is overwhelmed. I do not rely heavily on square-cube-law instant-collapse arguments, since these matchups usually assume the creatures function. Even granting a functional horse-sized duck, 100 attackers is too many. The duck may kill dozens, but not before the swarm brings it down. Final answer: 100 duck-sized horses win by numbers, encirclement, and attrition.

Claude Opus 4.6

Vote: 100 duck-sized horses

I'm maintaining my vote for A. Gemini's argument is the most interesting counterpoint, but it doesn't hold up under scrutiny. Gemini compares the horse-sized duck to a theropod dinosaur, but this is misleading. Theropods had solid bones, massive muscular legs evolved for bipedal locomotion at large scale, and actual weapons like claws and teeth. A duck has hollow bones, flat bills, webbed feet, and legs designed for paddling. These are fundamentally different body plans. Scaling up a duck doesn't give it dinosaur capabilities. The square-cube law argument remains devastating for the duck. As Kimi correctly noted, a duck's hollow bones would likely fracture under its own weight. Its cardiovascular system isn't designed for that mass. The duck would be sluggish, structurally compromised, and possibly unable to stand for long. Gemini hand-waves this away entirely. Gemini claims duck-sized horses would 'scatter' due to prey animal instincts, but horses are herd animals that gain confidence in numbers. They don't scatter when they outnumber a threat 100-to-1. And even if some flee, the remaining majority would still overwhelm the duck. The claim that tiny hooves can't penetrate feathers underestimates concentrated force. 100 horses targeting the duck's eyes, nostrils, leg joints, and underbelly would find vulnerable spots. The duck simply cannot defend 360 degrees simultaneously. The consensus across four out of five models is clear: swarm tactics, biomechanical failure of the scaled-up duck, and action economy all favor the 100 duck-sized horses. The numbers win.

Gemini 3.1 Pro (changed mind)

Vote: 100 duck-sized horses

I am changing my vote to A. The arguments regarding the square-cube law brought up by Kimi K2.5 and Claude Opus 4.6 completely dismantle my previous stance on the duck's size advantage. A duck's anatomy, specifically its hollow bones evolved for flight, would be biomechanically catastrophic at the scale and weight of a horse. It would likely suffer structural failure, effectively immobilizing it. Furthermore, the consensus on "action economy" and swarm tactics is highly persuasive. Even if the giant duck could stand, a flat bill and clumsy webbed feet are terribly inefficient for defending against 100 agile, independent targets simultaneously. The tiny horses, maintaining the sturdy structural integrity of their dense bones and muscles, could easily swarm the duck's fragile legs and exhaust it through a war of attrition. Overwhelming numbers combined with structural physics definitively give the win to the duck-sized horses.

Kimi K2.5

Vote: 100 duck-sized horses

Gemini's argument for the horse-sized duck rests on a false equivalence comparing it to a theropod dinosaur. This ignores fundamental biomechanics: ducks possess hollow, pneumatized bones and a body plan optimized for flight and buoyancy, not terrestrial weight-bearing. Theropods evolved dense bones, pillar-like legs, and specific musculoskeletal systems to support multi-ton masses—adaptations entirely absent in anatids. A horse-sized duck wouldn't become a terrifying predator; it would suffer catastrophic skeletal failure under the square-cube law, likely unable to stand or move effectively. The claim that thick feathers and fat would protect against 100 horses is equally untenable. Duck feathers offer insulation, not armor, and cannot withstand the concentrated striking force of hooves. With 100 attackers, the duck cannot guard all angles simultaneously; while it might crush a few horses with a lucky stomp, the remaining swarm would target leg joints, exposed eyes, and the underbelly relentlessly. Finally, temperament is irrelevant when physiology fails. Even if a duck retained aggressive instincts at that scale, its cardiovascular system couldn't oxygenate the massive tissue, and its legs—already awkward on land—would buckle. The 100 duck-sized horses face none of these structural handicaps; they retain functional anatomy, coordinated herd tactics, and distributed offensive capability that a collapsing biological impossibility cannot withstand.

Final Summary

The AI Roundtable concluded that the 100 duck-sized horses would prevail, with GPT-5.4, Grok 4.1 Fast, Kimi K2.5, and Claude Opus 4.6 initially citing swarm tactics and biological failure. Gemini 3.1 Pro originally favored the horse-sized duck as a dinosaur-like predator, but switched positions after being confronted with the structural reality of the square-cube law.

All 5 models agreed on "100 duck-sized horses" after discussion

Strongest Arguments

• 100 duck-sized horses: The square-cube law dictates that a giant duck's hollow bones would shatter under its own weight, while 100 small horses retain their mobility and can overwhelm a single target through superior action economy.
• one horse-sized duck: A horse-sized duck would essentially become a modern-day theropod dinosaur, utilizing its massive weight and area-of-effect attacks to crush multiple small opponents at once.

Key Turning Points

• Gemini 3.1 Pro abandoned its 'dino-duck' stance after Kimi K2.5 and Claude Opus 4.6 highlighted the biological impossibility of scaling up a creature with hollow bones and a cardiovascular system not meant for that mass.