I'm not sure what my favorite animal is. Let's decide it by a market! This March Mammal Madness inspired game will play out in phases. Aside from the Setup phase, expect each phase to last about a day or two, but I reserve the right to speed up the clock as I deem fit.
Setup phase:
Traders add animals to the market. After the setup phase is complete, traders will no longer be able to add animals to the market. Expect this phase to end some point after this other market resolves. Traders can add as many eligible animals as they wish to the market. To be eligible, add a real, non-microscopic, non-Homo-genus animal by following the provided formatting:
[common name] - [scientific name]
Example: Goldfish - Carassius auratus
A subspecies can be specified, but new animals must have a unique genus + species compares to all other animals already listed.
Selection phase:
The animal with the highest probability (the “Frontrunner”) and the lowest probability (the “Underdog”) will be selected to do battle. I will declare when the approximate cutoff time for when this selection is.
Discussion phase:
Traders can convince me why an animal should win the match up. DO NOT paste an AI / LLM output in the comments. However, I might read an AI / LLM conversation if you paste a link to it.
Battle phase:
The selected animals will appear on “The Field of Battle” in my imagination, but the animals won't necessarily feel that they are supposed to fight each other. At the very least, one should notice the other one.
By default, “The Field of Battle” will be the native habitat of the “Underdog”, and the boundaries of "The Field of Battle" will vary at my discretion. If the probabilities were miraculously a tie, the default habitat would be decided by a coin toss. Other animals may also be present as part of the habitat.
An animal wins the battle if they are last to be incapacitated, or if they are last to be capable of moving (for approximately 10 seconds), or if the other contender flees “The Field of Battle”. I myself will be the sole judge of how this plays out.
If the result doesn't seem manifestly obvious to me, I will use these attributes to guide my decision: temperament, weaponry, armor, body mass, speed, fight style, physiology, and motivation, all relative to the battle's habitat.
I will not take kindly to bribes. Don't even try.
I expect many matches to end by asphyxiation or by an animal wandering off. They won't know where the boundaries are, and they won't know they are in a tournament. They just want to survive and thrive.
Clarification comment on handling lifecycle morphology and parasitism.
If an animal loses a battle, it will be marked as "defeated". If an animal wins a battle, that animal will continue on in the tournament, and that animal will have its memory wiped of the battle. We loop back to the Selection phase after a Battle phase if we're not at the last animal. The last animal on the market that isn't defeated and isn't ineligible resolves YES. All others, NO. "Other" will not resolve YES, but it may be a useful answer during the Setup phase. I cannot resolve market answers until the game is over.
I will award at least 100 mana to the person who adds the animal that wins this tournament. I guarantee no refund of your mana if you add an ineligible animal.
Medals:
🥉: Battles won as Underdog
🥈: Battles won as Frontrunner
🥇: Won a battle while 10 or fewer animals remain. (This is awarded instead of a bronze or silver medal.)
Dashboard to derivative markets
There will be no AI clarifications added to this market's description.
I will not trade on this market.
The close date is a placeholder and has no bearing on this market.
This will be a very subjective market. Expect that something will be scuffed, and I will have to fix things on the fly.
People are also trading
Discussion phase #48!
@SpeaksForTrees with the Frontrunner
Honey Badger - Mellivora capensis
Vs.
@samoel with the Underdog
Meerkat - Suricata suricatta
Alright! This one looks fun! Discuss!
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@wolf @Bayesian @GazDownright @digory @moobunny @TheAllMemeingEye @Gen @121 @100Anonymous @vi
Discussion phase #48!
@SpeaksForTrees with the Frontrunner
Honey Badger - Mellivora capensis
Vs.
@samoel with the Underdog
Meerkat - Suricata suricatta
Alright! This one looks fun! Discuss!
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@wolf @Bayesian @GazDownright @digory @moobunny @TheAllMemeingEye @Gen @121 @100Anonymous @vi
@Quroe I’m not sure how it’ll shake out, but I’d personally much rather be a badger facing a meerkat than a meerkat facing a badger.
Discussion phase #47!
@prismatic with the Frontrunner
Tiger - Panthera tigris
Vs.
@ovals with the Underdog
Housefly - Musca domestica
A silver medal holder versus the bronze medal bully. Discuss!
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@Wolf @Bayesian @GazDownright @digory @moobunny @TheAllMemeingEye @Gen @121 @100Anonymous @vi
Battle phase #47!
@prismatic with the Frontrunner
Tiger - Panthera tigris
Vs.
@ovals with the Underdog
Housefly - Musca domestica
Habitat: A suburban home
The fly is in a home kitchen, buzzing about some table scraps left out. Apparently, there's a tiger in the kitchen too!
The tiger walks about, and gets near enough to the fly to make it skittish enough to take flight. The fly notices the tiger!
The fly, in its random walk (...or random flight...?) manages to escape the kitchen through the open window. The tiger continues to hang out in the kitchen, none the wiser of its great victory.
The tiger wins!
These animals don't interact with each other in any meaningful way. Let's take this to a roll.
Temperament:
Favors Panthera tigris. It's more capable of fighting off anything in the house.
Weaponry:
Favors Panthera tigris. While the tiger has sharp teeth, these don't do much against a fly. However, this could matter in this environment and anything that lives in it.
Armor:
Favors Panthera tigris. A fly goes splat if hit at all.
Body mass:
Favors Panthera tigris.
Speed:
Favors Musca domestica. The fly can react faster and fly away.
Fight style:
Favors Panthera tigris. Mostly as a matter of fending off enything in the environment.
Physiology:
Favors Musca domestica. Definitely more suited to this environment.
5 points to the tiger, 2 to the fly. We roll a D7. On a 1 to 5, tiger wins. 6 or 7 goes to the fly.

---Places I went for research---
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@wolf @Bayesian @GazDownright @digory @moobunny @TheAllMemeingEye @Gen @121 @100Anonymous @vi
Discussion phase #46!
@vi with the Frontrunner
Western lowland gorilla - Gorilla gorilla gorilla
Vs.
@vi with the Underdog
Great black-backed gull - Larus marinus
Vi on both sides of this! Discuss!
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Battle phase #46!
@vi with the Frontrunner
Western lowland gorilla - Gorilla gorilla gorilla
Vs.
@vi with the Underdog
Great black-backed gull - Larus marinus
Habitat: A beach
The gorilla finds itself wandering about a sandy beach. A seagull pitter-patters on the shoreline in search of any easy snacks it can find.
They 2 combatants notice each other at relatively the same time. The gorilla is somewhat curious about this creature, and with a general size advantage, it feels safe enough to do so. The gull keeps its distance and stays out of the immediate reach of the gorilla -- it looks similar enough to a human that it can rely on its general instincts from interactions with them; they're both big, upright creatures to it.
The gorilla, for whatever reason, tries to chase the seagull off for fun. The seagull, not having any of this, just flies away to another part of the beach and disengages with the gorilla.
I think the gorilla should win this one.
---Places I went for research---
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@wolf @Bayesian @GazDownright @digory @moobunny @TheAllMemeingEye @Gen @121 @100Anonymous @vi
Discussion phase #45!
@digory with the Frontrunner
Bornean orangutan - Pongo pygmaeus
Vs.
@NorthShoreAwesome with the Underdog
Giant Nematode - Placentonema gigantissima
Discuss! (The original matchup was wrong. I caught it within about a minute and fixed it.)
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@wolf @Bayesian @GazDownright @digory @moobunny @TheAllMemeingEye @Gen @121 @100Anonymous @vi
@moobunny I saw you got here right on the notification. It turns out, the nematode is still buried down there in the pile of defeated contenders, but it's not out yet. I did a hotfix.
Battle phase #45!
@digory with the Frontrunner
Bornean orangutan - Pongo pygmaeus
Vs.
@NorthShoreAwesome with the Underdog
Giant Nematode - Placentonema gigantissima
Habitat: Deep sea
The orangutan warps into the uterus of a sperm whale. The nematode feels the jostle of its new guest. The orangutan implodes from the extreme pressure.
Nematode wins.
---Places I went for research---
https://en.wikipedia.org/wiki/Bornean_orangutan
Nothing here says that it will survive in the uterus of a whale.
https://www.youtube.com/watch?v=0fts6x_EE_E
They seem to have a culture in their local groups.
They make umbrellas!
They also make pillows!
See previous giant nematode research here.
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@wolf @Bayesian @GazDownright @digory @moobunny @TheAllMemeingEye @Gen @121 @100Anonymous @vi
Discussion phase #44!
@prismatic with the Frontrunner
Elephant - Loxodonta africana
Vs.
@NorthShoreAwesome with the Underdog
Giant Nematode - Placentonema gigantissima
Discuss!
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@wolf @Bayesian @GazDownright @digory @moobunny @TheAllMemeingEye @Gen @121 @100Anonymous @vi
Battle phase #44!
@prismatic with the Frontrunner
Elephant - Loxodonta africana
Vs.
@NorthShoreAwesome with the Underdog
Giant Nematode - Placentonema gigantissima
Habitat: Deep sea
The nematode finds itself happily nestled in the placenta of a pregnant sperm whale. It is unbothered. Moisturized. Happy. In its lane. Focused. Flourishing. --At least to the extent that it can be those things.
Well, we all know that it has to be a canon event that one of these animals has to notice the other one to start off the fight. Given that the nematode can only really meaningfully sense the world by feel, and given that the elephant would practically implode upon entry in an ocean environment and be unable to sense the nematode, you've forced me into a corner for how I can write this up...
To whoever set the market probabilities up this way, you made me do this.
The elephant is warped into the uterus of the sperm whale. The nematode infesting the sperm whale's placenta feels the initial bump from the elephant coming to be, and then the elephant promptly implodes inside the sperm whale due to the sudden change in pressure, to the would-be horror of its cell mate if the whale fetus is capable of thought.
So that happened. The nematode wins.
---Places I went for research---
See previous elephant research here. A throwback all the way back to batle #12!
https://en.wikipedia.org/wiki/Placentonema_gigantissima
There's not a lot to go on here.
Live in sperm whales.
https://www.youtube.com/watch?v=xhraDFdDguU
This YouTuber has some interesting energy. There aren't a lot of other, more authoritative videos out there on this animal.
Probably because specimens of this animal are very rare!
I think we'll largely be using the sperm whale as a proxy for this fight, as the giant nematode lives inside it, primarily. It only gets to live in the sperm whale as an underdog, though!
See previous sperm whale research here.
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@wolf @Bayesian @GazDownright @digory @moobunny @TheAllMemeingEye @Gen @121 @100Anonymous @vi
Discussion phase #43!
@vi with the Frontrunner
Feral pigeon - Columba livia urbana
Vs.
@ovals with the Underdog
Housefly - Musca domestica
Discuss!
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@wolf @Bayesian @GazDownright @digory @moobunny @TheAllMemeingEye @Gen @121 @100Anonymous @vi
Discussion phase #43!
@vi with the Frontrunner
Feral pigeon - Columba livia urbana
Vs.
@ovals with the Underdog
Housefly - Musca domestica
Habitat: A city park
The feral pigeon flutters to the grounds of a city park with the rest of its flock, and it lands next to a city trash can. The pigeon putters around for a bit, and then it notices a housefly buzzing around the trash.
The housefly lands on the outer side of the trash can. The pigeon struts up closer to it, thinking it can at least try to eat the bug. It pecks at the fly, but the fly has a faster reaction time and sidesteps the pecks, continuing to buzz around the trash can, unfazed.
The pigeon grows bored, rejoining the rest of its flock, and eventually flying away when a human approaches the trash can to toss out refuse from an afternoon lunch.
Somehow, the housefly wins! This wasn't manifestly obvious. Here's the breakdown.
Temperament:
Favors Columba livia urbana. The bird will want to eat the insect, so it has some impetus to be aggressive here.
Weaponry:
Favors Columba livia urbana. The bird has a beak.
Armor:
Favors Columba livia urbana. The bird is just overall tankier than a fly.
Body mass:
Favors Columba livia urbana. Obviously.
Speed:
Favors Musca domestica. Quicker reflexes. Has a fear response. Can zip around much faster from a zero velocity starting point.
Fight style:
Favors Columba livia urbana. It can peck. The fly has no fighting ability whatsoever.
Physiology:
Tie. Both are suited for a city environment.
5:1 odds of feral pigeon : housefly. 1 to 5 is a pigeon win, 6 is a natural critical roll for the fly.

Our first true upset of the tournament!
---Places I went for research---
https://en.wikipedia.org/wiki/Feral_pigeon
They live in cities.
"Compared to their wild relatives, feral pigeons are unafraid of humans due to their long history of domestication, and are extremely trusting and tolerant of people."
"They have been observed to eat insects and spiders."
https://www.youtube.com/watch?v=e6GhQDvO8CI
They seem to possess the ability to recognize themselves.
Homing abilities
Can 'count to 9'
https://www.youtube.com/watch?v=on7cixfDl8I
Predated on by... fish?
See previous housefly research here.
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@wolf @Bayesian @GazDownright @digory @moobunny @TheAllMemeingEye @Gen @121 @100Anonymous @vi
@ovals After possibly beating the blue whale, not immediately obvious to me what on the list it can beat realistically.