Interspecies Conflict/bears vs cats
1)650kg grizzly bear vs 2x 250kg bengal tiger
2)650kg grizzly bear vs 3x 140kg sumatran tiger
3)300kg american black bear vs 200kg african lion
4)1200kg pleistocene polar bear vs 3x 250kg bengal tiger
5)1600kg actotherium angustidens vs 4x 250kg bengal tiger
6)1600kg actotherium angustidens vs 6x 150kg lioness
7)650kg grizzly bear vs 6x 80kg leopard
8)200kg asian black bear vs 100kg jaguar
Megatherium vs bears and cats
1)5tone megatherium vs 3x 650kg grizzly bear
2)5tone megatherium vs 1x 1600kg arctotherium angustidens
3)5tone megatherium vs 8x 250kg bengal tiger
4)5tone megatherium vs lion pack (2x lion + 8x lioness)
5)5tone megatherium vs 3 tone hippo
Thanks for the answer
1)650kg grizzly bear vs 2x 250kg bengal tiger: Grizzly bears are among the most aggressive of all bears, and have great durability & endurance. These bears are also well armed, with strong jaws, long claws (10cm), & stocky forelimbs that can be used to control positioning or deliver powerful swipes (this aided by a huge shoulder hump of muscle). Bengal tigers are fantastic hunters, and although they are typically solitary, occasionally hunt in pairs. They are quick, athletic, well-armed (sharp teeth & claws), & practiced at killing large animals. 2 Bengal tigers are certainly capable of subduing this huge bear, but will have trouble doing so on most occasions. The bear will be much stronger, will have the stamina to battle strongly even when the tigers begin to fatigue (cats are built for short bursts of explosive action and will have a small window of time in which to overcome the bear), and the flexibility to turn quickly to counter-attack each tiger as it comes in contact with it (which, along with the bear's stout neck, will make it a more difficult target to finish with a throat bite than a typical prey item). Edge to the 650kg grizzly.
2)650kg grizzly bear vs 3x 140kg sumatran tiger: Big cats like tigers are a good match one-on-one with bear close to their weight range, but will have difficulty (even in a group) finishing one much larger. Sumatran tigers are fierce, powerful felids that usually hunt solo, and won't engage in a battle as a group with the same level of experience & precision as a group of lionesses. Tigers typically kill with a throat bite (to induce suffocation) or neck bite (to sever the spinal cord), and this will be a tough task for any cat with an ursid weighing almost 5 times as much. The grizzly bear will have huge advantages in strength, durability, & endurance. Very dangerous battle for the 3 tigers, and they aren't without hope, but they won't prevail on most occasions. 650kg grizzly bear wins.
3)300kg american black bear vs 200kg african lion: Black bears aren't as formidable pound-for-pound as brown bears, but still have the ursine assets (strength, durability, endurance, jaws & paws, etc.) that make them capable combatants. American black bears are largely omnivorous (only 5% of their intake is meat), and are experts at climbing trees (with short, sharp claws). Male African lions commonly battle other male lions to protect females & territory, but do not encounter bears of any kind in the wild. The lion in this battle will have advantages in quickness, agility, & killing know-how, but the bear will have more strength & stamina. A 200kg lion can overpower many animals that weigh more than 300kg, but a bear is able to fight back better than many of the lion's typical prey items. With animals like buffalo, zebra, & wildebeest, the lion can quickly get into a position to administer a neck bite, and the physiology (namely the lack of a flexible body & limbs) of the prey item makes this action hard to defend. The lion can win this, and the battle will be close, but the bear has too much size to not be favored. Edge to 300kg American black bear.
4)1200kg pleistocene polar bear vs 3x 250kg bengal tiger: This matchup is similar to #2 (650kg grizzly bear vs 3x 140kg Sumatran tiger) when the weights are considered. The Pleistocene polar bear was similar to a modern-day polar bear, but was over 1.8 meters at the shoulder (as opposed to 1.5 meters). These bears had relatively slender bodies (to aid in swimming), a thick layer of blubber under their fur, and great strength from nose-to-tail. I would give 3 250kg Bengal tigers a better chance of overcoming a 1200kg buffalo than a 1200kg bear due to the bear's physical attributes (namely clawed forelimbs & supple body). Again, the tigers aren't without hope, but won't be favored against this huge bear. 1200kg Pleistocene polar bear wins.
5)1600kg arctotherium angustidens vs 4x 250kg bengal tiger: Among modern-day bears, Arctotherium was related most closely to the Spectacled bear (but weighed around 9 times as much and measured over 2 meters tall at the shoulder). Spectacled bears occasionally prey on livestock, but are primarily herbivorous. Arctotherium may have been an active carnivore. Bengal tigers are experts at overpowering animals much larger than themselves solo, but most of their prey items don't have the assets of a bear (endurance, clawed forelimbs, jaws, etc.). Tigers encounter bears on occasion, but ursids and felids are usually closely matched at similar weights. If this battle was scaled down, it would be like a Spectacled bear being attacked by 4 Arabian leopard-sized tigers. The tigers can certainly cause problems for it, but this bear is huge. 1600kg Artotherium angustidens wins.
6)1600kg arctotherium angustidens vs 6x 150kg lioness: Lionesses are excellent at using teamwork to tackle large prey, but the Arctotherium will present a tougher challenge than a typical herbivore because it can use its paws & claws to swipe at the attacking lionesses. One of the lionesses will need to get into a position to apply a throat bite to defeat the bear, because the cats' paw swipes won't be as effective as the counter-strikes from the Arctotherium. A successful throat bite will be hard to complete because the huge bear can use its front paws to dislodge a lioness from its neck. If this battle was scaled down, it would be like a Spectacled bear being attacked by 6 ocelot-sized lionesses. The Arctotherium is simply too big here. 1600kg Arctotherium angustidens wins.
7)650kg grizzly bear vs 6x 80kg leopard: Leopards are great hunters, and are well known for dragging heavy prey items up into trees. Leopards are battle-tested, occasionally dealing with hyenas, baboons, & even lions. The leopard is a solitary hunter, and will not be as adept at fighting as a group as lionesses will be. A 650kg grizzly bear can dispatch a 80kg leopard with a well-placed paw swipe, and will be a tough adversary for a group of 6. The leopards will find it hard to execute a successful throat bite on such a strong, stocky animal, and the grizzly bear's violent resistance will make it close to impossible. Leopards typically back down if a fight gets down & dirty (they can't hunt effectively if they get injured), and a group of 6 won't make enough headway with the grizzly bear before they become tired & uninterested in continuing. 650kg grizzly bear wins.
8)200kg asian black bear vs 100kg jaguar: Jaguars are the strongest big cat pound-for-pound, and have jaws strong enough to penetrate turtle shells and caiman armor. They typically kill prey with a skull bite or a bite to the back of the neck (to sever the spinal cord). Jaguars have relatively short legs and a stocky, powerful body. Asiatic black bears eat fruit, nuts, leaves, insects, etc., and are not as robustly built as brown bears. Asiatic black bears will typically fight by standing on their hind legs and swiping with their paws. In a realistic encounter the black bear will probably succeed in chasing the jaguar away. The bear's endurance will enable it to gain the upper hand in a long conflict, but a jaguar's killing experience & weaponry are great assets. At these sizes, the Asiatic black bear will be stronger, and it will be able to defend itself well from the smaller jaguar. A 150kg jaguar will give the black bear a great fight, but a 100kg one will have great difficulty. Edge to 200kg Asian black bear.
Megatherium vs bears and cats
1)5tone megatherium vs 3x 650kg grizzly bear: Megatherium was a giant ground sloth that measured 6 meters tall when standing upright. It had a tough hide underneath its fur made of small pieces of bony (similar to the osteoderms of crocodilians) that formed an armor like chain mail. Megatherium also had huge forelimbs armed with large claws, and these likely made great weapons. It was believed to be carnivorous, but likely drove other predators off of carcasses with its tremendous size. Megatherium was probably a slow-moving mammal, but was likely capable of mounting a formidable defense by staying in one place and swiping with its massive claws. Grizzly bears are strong, aggressive ursids that are capable of overpowering large cervids like moose & elk on occasion, but would have no clue how to proceed against an animal as large as Megatherium. The bites & swipes of the grizzly bears would have minimal effect on the giant sloth's hide, and they would not be strong enough to wrestle it into a vulnerable position. The Megatherium would quickly drive all 3 grizzly bears away. Megatherium wins.
2)5tone megatherium vs 1x 1600kg arctotherium angustidens: No bear is made to tackle animals weighing close to 3 times as much as it does. Arctotherium would have a hard time penetrating the tough hide of Megatherium with its teeth & claws, and wouldn't have been able to avoid getting hit by the giant sloth's huge, clawed forelimbs. The Megatherium simply has too much size here. Megatherium wins.
3)5tone megatherium vs 8x 250kg bengal tiger: The Megatherium's great size and protective hide will be great defensive assets against the 8 Bengal tigers, but its lack of speed & mobility will mean it can't prevent the tigers from leaping upon it. A swipe from the Megatherium's huge forelimbs could easily dispatch a tiger with a direct hit, but tigers have great speed & agility. The 8 tigers won't be able to easily latch on with a successful neck bite against such a large animal, and will only hope to overcome it by continuous biting & clawing to induce blood loss. The Megatherium's armor-like hide will make breaching it very difficult, and the endurance of big cats isn't great. The sheer weight of all 8 tigers might be enough to cause Megatherium to collapse if they leap upon it at one time, but it's unlikely the tigers will intentionally strategize this way. A stalemate may ensue, but the Megatherium has the assets to survive this encounter and eventually drive the tigers away. Edge to Megatherium.
4)5tone megatherium vs lion pack (2x lion + 8x lioness): Lions work well together as a team, but will faced with the same problems the tigers will encounter in the previous matchup. There's not many vulnerable areas on Megatherium for the lions to exploit, and the cats don't have the endurance to keep up an attack long enough to overcome such a huge, well-protected animal. If Megatherium's endurance was poor, it would open up a small chance for the lions (or the tigers in the previous matchup) to succeed if certain things fell into place. Using their weight to collapse the giant sloth would be a necessary action, and finding vulnerable areas to claw & bite would be another. A large group of lions sometimes have difficulty with a 680kg Cape buffalo, and Megatherium is much, much larger. Edge to Megatherium.
5)5tone megatherium vs 3 tone hippo: Megatherium, when standing, is over 4 times as tall as the shoulder height of a hippopotamus. Hippos can be very aggressive, and are very territorial when near the river's edge. They have huge jaws that open over a meter wide, and are armed with long canines & incisors to bite, slash, & stab with. Hippos aren't built to move about on land for extended periods of time (rotund bodies/comparatively small legs), but are capable of quick bursts of speed. As dangerous as a hippopotamus can be, it will have a hard time penetrating Megatherium's tough hide well enough to cause serious injury without having enough time to mount repeated assaults. Megatherium's swiping claws won't easily breach the thick (15cm) hide of the hippo, but repeated blows to the smaller animal's body (especially to the head) will take their toll. The Megatherium is better protected from the hippo's offense than the hippo is protected from Megatherium's offense. The hippo would have a better chance if the weights were closer, but here the giant sloth has too much size. Megatherium wins.