Interspecies Conflict/Past vs Present
The following fights are at average sizes unless specified otherwise.
1. Herrerasaurus (about 4.5m long) vs. Silverback Gorilla
2. Tylosaurus vs. Sperm whale
3. Ngandong tiger vs. Saltwater crocodile
4. Albertosaurus vs. White rhino
5. Ornithocheirus vs. Harpy eagle
6. A small Liopleurodon (about 15ft) vs. A family of giant otters (8 adult members) in shallow and deep water.
7. Abelisaurus vs. Lion pride (2 males, 6 females)
8. Noasaurus vs. Bobcat
9. Titanis vs. Anaconda
10. Guanlong vs. Cougar
11. Crylophosaurus vs. Pack of wolves (8 adult members)
Sorry if this question is a bit long.
1. Herrerasaurus (about 4.5m long) vs Silverback Gorilla: A Herrerasaurus 4.5 meters long would have weighed about 13% more than a silverback gorilla. Herrerasaurus was an powerful theropod with long jaws filled with sharp, backward-curving teeth (to grasp struggling prey). Its strong hind legs enabled it to run swiftly, and its long tail enabled it to make rapid turns while running. Gorillas are strong primates with long arms & a decent bite, but they aren't accustomed to taking on similar-sized animals of another species. They typically use an intimidating display to repel rivals. Herrerasaurus didn't tackle prey items close to it own weight, and the gorilla would likely put up enough resistance to make the attacking theropod lose interest. A determined Herrerasaurus would have the weaponry (and strategy instincts) to overcome a silverback gorilla, but might not succeed every time in a realistic encounter.
2. Tylosaurus vs Sperm whale: A sperm whale is many times heavier than a Tylosaurus. Tylosaurus was a very agile aquatic predator with 4 flippers & a rudder-like tail. It had large jaws lined with sharp teeth used to crush & tear into prey items. Sperm whales typically feed on soft-bodied animals (cephalopods), but have the assets to repel a Tylosaurus. The mammal's huge head can be used as a battering ram, and its tail can be used to strike. The sperm whale's lower jaw is armed with banana-sized teeth, and its bite would be able to injure the much smaller Tylosaurus. Tylosaurus is a much more formidable animal pound-for-pound, but the sperm whale is simply too big. Sperm whale wins.
3. Ngandong tiger vs Saltwater crocodile: The saltwater crocodile will weigh about 2 1/2 times as much as the Ngandong tiger. The saltwater crocodile has a huge set of jaws that can slam shut with astounding force, and they are used to clamp onto prey items to drown them. It is also largely covered in osteoderms (bony growths) that provide protection from many attacks. Crocodiles have poor mobility & stamina on land, but can still move with quick bursts of speed. Tigers are agile & well-armed (jaws & claws), and are practiced at completing kills against larger animals (including crocodiles). A Ngandong tiger will have a decent chance to overpower a saltwater crocodile on land, but it must tire the reptile out first to ensure the greatest success. As long as the tiger avoids the powerful jaws of the crocodile, it can leap on its back & attack the neck area. A crocodile in water is a much more dangerous adversary because its mobility & stamina are greatly increased, and its famous "death roll" can be used to much greater effect. The Ngandong tiger can defeat a saltwater crocodile in shallow water, but it will be facing a perilous uphill battle. Close to 50/50 on land (slight edge to the Ngandong tiger); saltwater crocodile wins in water.
4. Albertosaurus vs White rhino: These animals will typically be close in weight, but a large white rhino can weigh around 50% more. White rhinoceroses have tank-like bodies, tough hides, and a long frontal horn that can be used to gore adversaries. Albertosaurus was lightly built compared to other tyrannosaurids, and was likely capable of capturing fast-moving prey. It had strong jaws with serrated teeth (like steak knives) used to slice & saw through flesh. White rhinos don't deal with similar-sized predators, but Albertosaurus dealt with similar-sized prey items. A parity battle would slightly favor the predatory Albertosaurus, but a white rhinoceros with a decent weight advantage would prevail more times than not.
5. Ornithocheirus vs Harpy eagle: Ornithocheirus was a pterosaur with a wingspan 3 times greater than a harpy eagle's, but may have weighed only 2 or 3 times as much. Ornithocheirus ate small animals (fish, squid, etc.) it could catch by skimming the surface of the sea & grabbing them in its large jaws. Its snout was wider toward the end than at the base (somewhat like a slender gourd), and its teeth were slim & pointed. Harpy eagles are powerful raptors capable of killing large mammals & reptiles, and are armed with strong talons & a sharp beak. The harpy eagle would have a decent maneuverability advantage over Ornithocheirus in the air, and could attack the pterosaur repeatedly without significant worry of a counter-attack. The larger Ornithocheirus would have a good chance of faring well in a ground confrontation (by biting with its jaws), but the harpy eagle has the overall advantage.
6. Liopleurodon (15ft) vs 8 giant otters (in shallow and deep water): A Liopleurodon at this length would weigh almost a ton, and it would dwarf the giant otters. Otters are very agile in the water, are intelligent, and have sharp teeth. Liopleurodons had 4 flippers that enabled them to maneuver well through the water & ambush prey with quick bursts of speed. Their jaws were huge, powerful, and full of pointed teeth. The Liopleurodon would have been able to dispatch an otter with a single bite, and would have had enough mobility to catch them as they attacked. The otters would have needed a large accumulation of bites to effect the pliosaur, and their numbers would be reduced before they could accomplish this. Liopleurodon wins.
7. Abelisaurus vs Lion pride (2 males, 6 females): Abelisaurus weighed approximately a ton. This theropod had a oddly-shaped jaw; the lower mandible was slender & delicate compared to the rest of the skull, and it may not have been able to deal with large, struggling prey as a result. Abelisaurus could certainly have killed a lion with its jaws, but may have struggled with a pride the size of the one being used here. Lion prides are adept at tackling large, dangerous herbivores that approach the weight of Abelisaurus (Cape buffalo, giant eland), and would have a good chance to overpower the reptile working as a team. The pride may lose a member or 2 in the process, but 8 of them should get the job done. Lion pride wins.
8. Noasaurus vs Bobcat: Noasaurus was slightly heavier than a bobcat. Noasaurus was a small theropod with a decent bite & a sharp claws. These sharp claws were originally thought to be attached to the foot, but many paleontologists now believe they belong with the hand (a similar issue arose with Megaraptor). Regardless of the location of the claws, this battle would depend somewhat on how well Noasaurus was able to use them in a conflict. Bobcats are quick, agile, and well armed (claws on each paw, sharp teeth), and can be fierce fighters. Probably close to a 50/50.
9. Titanis vs Anaconda: A green anaconda weighs about 20% more than Titanis did. Titanis was one of the "terror birds" that had large beaks for biting & striking, and strong legs for running & (perhaps) kicking. Anacondas are great ambush predators, but are poor face-to-face fighters on land against similar-sized animals due to poor mobility & stamina. Although the anaconda would have the strength to overpower Titanis in its coils if it could latch onto it, the weaponry of the large bird would give it a chance to launch an effective counter-attack. Titanis would likely initiate the attack by using its feet to hold the anaconda in place while it used its beak to bite & strike. The anaconda would have much greater success in water (where its mobility & stamina would be much greater), but Titanis would still have a chance to prevail. Titanis wins on land; edge to anaconda in water.
10. Guanlong vs Cougar: The cougar weighs a little bit more than Guanlong did. Guanlong was a theropod with a decent bite, but it would have had trouble dealing with the cougar's agility & athleticism. Cougars are capable of tackling prey items weighing several times more than Guanlong, and the felid would have treated the dinosaur in much the same way. Guanlong would have possibly gotten a bite or 2 in during a battle with a cougar, but the cat would quickly get into position to apply a finishing bite (quite possibly after tackling the dinosaur to the ground). Cougar wins.
11. Crylophosaurus vs. Pack of wolves (8 adult members): Crylophosaurus weighed at least as much as 8 adult grey wolves combined. The only remains of Crylophosaurus are from one not fully mature, so its size is uncertain. It was a theropod, with shallow jaws & a slender build. Grey wolves are fantastic pack hunters, and would have enough lateral mobility to avoid many of Crylophosaurus' bite attempts. It would be important for the wolves to avoid the jaws (and perhaps an inadvertent swipe from the tail) while employing a "bite & retreat" method of attack (to wear the dinosaur down), but more importantly when they secure a bite & hold on. Because these animals will not have encountered each other before, there would be a "feeling out" process that might lead to mistakes. However, wolves are quite intelligent & adaptable, and would have a decent chance to prevail if caution is exercised. 8 wolves would have a good chance of overcoming a bull elk (which can weigh more than Crylophosaurus), and should have the edge over the dinosaur if they avoid its jaws the same way they avoid the cervid's antlers & hooves. Grey wolves have the slight edge over the known version of Crylophosaurus, but a larger version (that might be a full-grown adult) would be too large for the canids to handle.