Interspecies Conflict/snake fight
Gaboon viper vs mussurana
ball python vs kingsnake
black mamba vs gaboon viper
reticulated python vs anaconda
eastern diamondback rattlesnake vs gaboon viper
20ft reticulated python vs 18 ft king cobra
8 ft indigo snake vs 6ft king snake
Gaboon viper vs mussurana: The gaboon viper is at the top among the world's heaviest venomous snakes. It also has the longest fangs of any snake (as long as toothpicks) and the greatest potential venom output with each envenomation as well. The mussurana predates upon pit vipers (among others) and is immune to their venom, but the gaboon viper resides on a different continent (Africa) and its venom may hazardous to the smaller snake. The mussurana kills by constriction, and it's unlikely it will be able to move its body like it wants to when it makes contact with an opponent so much larger than it is (even though that opponent is not a constrictor itself). Edge to gaboon viper.
ball python vs kingsnake: The ball python will be heavier and more robust than the kingsnake (even if we use the common kingsnake, which is the largest), but the kingsnake will have some advantages. The kingsnake predates upon other snakes, and is probably more confrontational than the larger snake. Many of the snakes the kingsnake preys upon aren't constrictors themselves (like rattlesnakes), and the ones that are constrictors probably don't enjoy the weight & strength advantage that the ball python will in this matchup. I would back the kingsnake at close weights, but a large ball python can weigh 2-3 times more than it does. Edge to ball python.
black mamba vs gaboon viper: The black mamba will be at least twice the length of the gaboon viper, but will only be a fraction (maybe 1/4) of its weight. The black mamba's venom is more potent, but the gaboon viper can potentially inject a much greater amount of venom per bite. It's very likely both snakes will land bites shortly after the onset of the battle, but the key will be how each snake's venom will affect the other (which is subject to supposition). The gaboon viper's strike is incredibly fast, but the black mamba will often strike repeatedly. The gaboon viper's bite will inject more venom, but the black mamba's bite will inject venom that may be more effective on a drop-for-drop basis. The larger size of the gaboon viper will be a factor as well when the effects of venom are considered (will likely take longer for any toxin to spread throughout its body). Both snakes may die from any hostile encounter (the black mamba will be the likely aggressor, but the gaboon viper will land a retaliatory bite as soon as it's attacked), and without knowing the actual effects of each snake's venom on one another, there's no easy way to determine which snake will be the most dominant at various stages of the battle. Probably a 50/50.
reticulated python vs anaconda: The python will be longer than the anaconda, but will weigh much less (assuming we use the green anaconda). The reticulated python will likely have the edge in aggression, agility, & quickness, but those assets won't serve it well once the snakes make contact. The more powerful anaconda will probably be able to coil & force its position with greater ease than the python will, and should be able to bully the lighter snake more times than not. It will be difficult for either snake to constrict the other (but not impossible), so it will likely play out with the anaconda dominating long enough to drive the python away. I would favor the reticulated python at equal weights, but not at usual weights. Edge to anaconda.
eastern diamondback rattlesnake vs gaboon viper: These snakes will be similar in weight. The Eastern diamondback rattlesnake will be longer; the gaboon viper will have a thicker body. Both are rapid strikers, and any hypothetical hostile encounter will surely lead to both snakes getting bitten very early in the battle. The gaboon viper's fangs are twice as long, but either snake should have no trouble injecting its venom into the other. As with some of the other matchups, how profoundly and quickly the venom of each snake affects the other is one of the key elements in determining which snake will be more dominant at various stages of the battle. The gaboon viper can inject more venom per bite than any other snake on the planet, but the diamondback rattlesnake isn't far behind. It's possible if the gaboon viper bites and holds on (which it does with prey) the rattlesnake will have an opportunity to land multiple counter-bites (it doesn't typically "hang on" to something it bites), and it may be able to inject more venom this way. Much of this is conditional, but I'd give the slight edge to the Eastern diamondback rattlesnake.
20ft reticulated python vs 18ft king cobra: The reticulated python will weigh at least 10 times more than the king cobra, but weight won't necessarily be the most important aspect of this battle. A king cobra's bite can potentially kill very large mammals (even elephants), and it's quite possible that many reptiles will be at serious risk as well if bitten. King cobras sometimes kill and eat small pythons, so its venom may affect the larger reticulated python. The python will have the size and strength to control any positioning, and it can eventually constrict and swallow the smaller cobra if the cobra's venom doesn't affect it quickly enough. However, the king cobra's potential venom output is second in volume only to the gaboon viper, and its initial bite might be able to keep the python from successfully advancing its own attack. The python may kill the cobra and die soon after from any envenomation it receives. There's a bit of guesswork here, and it primarily hinges on how profoundly the king cobra's venomous bite will effect the reticulated python. It can likely go either way, but I'd actually be more worried for the python in this battle than the cobra. It's conditional, but edge to king cobra.
8ft indigo snake vs 6ft king snake: The indigo snake can weigh a lot more than the kingsnake, even close to double its weight. Both snakes are constrictors, and both occasionally predate upon rattlesnakes (and are immune to the venom of the rattlesnakes they prey upon). With these snakes having similar abilities and attributes, size and weight will be the determining factor. Edge to indigo snake.