#Like the numbers would change but pretty clearly the overall picture wouldn't really

[maeamian]

imagine 2 of each bear (black, brown, panda, and polar) in the 4 corners of the u.s. they are going to the center of the u.s. for glorious battle to determine who is the best bear. on their way, they are mating to expand their army exponentially. once they meet in the middle, who would win?

Extremely good question and I am glad you asked.

Obviously there are several factors to consider, so as a trained astrophysicist my first instinct is to ignore as many as possible. So first of all, I'm assuming we're talking the continental united states and therefore the geographic center thereof in Lebanon KS. I'm assuming that we're looking at corners in roughly Bangor, Maine; Seattle, Washington; Miami, Florida; and San Diego, California. I am almost positive this distribution shouldn't have a major impact, but to ensure fairness let's distribute them in what's as close as possible to their home ranges. For the polar bear this is the trickiest since their range doesn't extend that far south, but it's closer to Maine than it is to Washington, for the Brown bear, it's a little out of home in Seattle but not in Washington but that's not going to matter, the black bear can live in Florida and that leaves the Pandas in San Diego which they are not native to, but since they aren't native to North America we can imagine these escaped from the San Diego Zoo's wonderful panda exhibit. The only useful piece of information I'm deriving from all of this is that it's 1440 miles driving from San Diego to Lebanon, KS, I'm not going to bother checking the other locations and instead we can just adjust the starting locations to get that distance right, it's not direct but it does reflect the geographic contours well enough, we can use that as our baseline distance for all four bears plus now we can imagine this scenario more fully in our heads, which is always a plus.

So now we've got a few more questions to answer, firstly, how long is it going to take them to get there? The Pandas are going to be a major outlier and we'll get to them later, but for now let's take the Grizzly as the median bear out of the other two, they can run at a top speed of about 35 mph, but have a more comfortable canter at about 3 m/s which is a bit under 7 mph, given the distance they're traveling it's going to require a little over 200 hours of travel time to get to the geographic center of the US for the three more normal bears. Assuming that they spend no more than 6 out of every 24 hours traveling and the rest of the time covers the fuckin' and huntin' and foragin' that'll be required to establish these bear armies, but it also leads me to my next worrying point which is that if these bears are dedicated to getting there, even at pretty casual paces, that's only 800 hours, which is slightly over a month. The problem that leaves us with is that no bear has a gestation period of under a month, we're looking at a range of 6-9 months (nice) on the three bears in question, which means that of those three non-panda bears, each will only end up in the middle of the country with the pair they started with, and we'll get to them in a bit but first it's time to consider the outlier: the Giant Panda.

As mentioned before, the Giant Panda is the only one in this selection not native to North America, and only recently were proven to be True Bears, sharing taxonomic qualities with the Raccoon family as well, it is most basal species of bear, being equidistant from all other living bears in terms of relations and the furthest back to branch from the common ancestor. It's also a bit of a head-scratcher because they have to spend half their lives, as in 12 hours out of every day, eating because they eat a very inefficient food source in the form of bamboo. They're also noticeably slower, traveling in general at a calm 1.5 miles per hour, moving an average of less than a mile per day because most of it is back and forth foraging for food, but if they're dedicated and aim all of it in one direction that means they can manage the trek from San Diego in a cool 960 hours of traveling, and given their absurd diet and the need to sleep and do other things as well, it's likely they can't spend more than 3 hours of their 24 doing the traveling, but let us assume that rather than them having escaped from the San Diego Zoo this whole experiment is orchestrated by zookeepers gone mad with power, but of course they're still zookeepers so let's at least make sure that the pandas have a traveling food source to account for the fact that they can't hunt and forage in North America for what they eat because otherwise the answer here is 'they starve and do not impact the bear fight', but that also means that the 960 hours of travel time will translate into a fuller 7,680 hours of regular time given all their other needs, this is still only 320 days, and given that they have a gestation period of an average of 4.5 months, is enough for two of those, let's ignore basic biology some more here (I'm an astrophysicist not a gynecologist) and imagine that somehow means our panda could show up with two litters of cubs but they'd do so about nine months late.

So this leaves us with six more normal bears who have shown up in the middle of the country, from here there's two general classes of outcome that I think are the most likely, although by no means does this cover every possibility. The first is that the three sets of bears form a sort of uneasy truce in the middle of the country waiting for the pandas to show up and deck it out in the agreed-upon four way brawl that was set up. The second is that the bears who show up duke it out and the winner takes on the Pandas. I do not think these are substantively different scenarios, given that the pandas are not built for fighting or hunting in the slightest they aren't going to be a major impact on the actual battle so much as the major factor in the time component of this question, in either case whatever bears are taking on the Pandas will only have one set of cubs, given that those 6-9 month gestation periods can't occur twice in the 10 month period we're looking at EVEN if we ignore biology as all physicists are inclined to do, but most bears reach maturity around three or four years so no one but the original pair will be contributing cubs to the fight.

When it comes to the three bears I'm not going to waste too much of your time, the size and strength of these three bears from least to most is Black, Brown and then Polar. Black bears have wider ranges and are more adaptable but Brown Bears are bigger and stronger than them by enough that won't matter. Polar Bears are bigger and stronger still, and once again would kick the Brown Bear's asses. There's a million ways it could theoretically go, of course, and any given day any given fighter can win any given fight, but on average you'd expect the polar bear to dominate the three way melee, the only question is if the Panda's extra litter of cubs matters and I'm going to once again skip to the easy answer: no polar bears eat meat almost exclusively, the tools they have at their disposal are just not going to be stopped or stoppable by a plant-eater even one with genuine claws like the Panda.

Unfortunately, the distance they're traveling just isn't enough for the time to add up to let the exponential growth be an important factor here so it's primarily a question of which bear wins in a fight and that's a pretty known answer among bear enthusiasts (not that kind, although shout out to the other kind of bear enthusiast too!) This is a fantastic question and I'm glad you asked it, but I think we might need to look at larger distance scales for the armies to be truly mighty by the time they arrive, you'd want at least 4 years, say, so that a second pair of bears comes online, as it were, and working backwards from that we're looking at a year's travel time and at 7 mph, we're looking at about 61,000 miles or about a quarter of the way to the moon, in fact a walk to the moon and back might just be the right distance to make both combat strength and the breeding speed (for which the non-polar bears do have some advantages) come into account but before the number of bears becomes the dominant factor (which Pandas might be able to compete in, ignoring the historical realities of the situation; they do at least have shorter gestation periods by a noticable factor)

#lmao always feel free to send asks like this I enjoy a fun thought experiment #You can also see here that if I messed up in the distance or speeds by a factor of like 5 or less it should still be the same #Like the numbers would change but pretty clearly the overall picture wouldn't really #Since cubs are not productive fighters