Is there a difference fighting against people versus animals?
Yes. Yes, there is. For one thing, very few animals come with combat training. For another, a person cannot, for the most part, replicate the defensive attributes of most major predators or even most herbivores on their own.
Bows, spears, snares, traps, and slings are the historical methods with which people hunted. You need to keep a fairly significant amount of distance between yourself and the animal to avoid the teeth, hooves, claws, charging, and any number of other attributes which will leave your hunter very dead in fairly short order. Even with all the necessary precautions and use of appropriate weaponry/assistance of domesticated animals (horses, hunting dogs, whatever), there are no guarantees.
Herbivores like deer, buffalo, and other big game animals are exceedingly dangerous when put under threat. It’s best to get the Disneyfied idea that the only animals that will threaten your hunters are the big predators like lions and wolves. No, it’s the deer and the buffalo they should be looking out for. Herbivores can be very aggressive, they are also very large and very agile. After the mosquito and it’s good friend malaria, the most dangerous creature in Africa is the hippo. Knights used spears and lances when they hunted boar and even then many did die by getting gored on very sharp tusks.
If you’re really planning to write hunters than brushing up on your nature documentaries (and Animal Planet’s When Animals Attack) may not be a bad idea. You may also want to look into documentaries, studies, and other literature about the social structure/history of indigenous cultures around the world. You may also want to check with your local Fish and Wildlife Bureau (or corresponding group in your local country) to see what they suggest for more information on hunting and anthropology departments at your local college/museums to see if there are any suggestions for beginning good sources to brush up on. I also suggest checking with your local librarians to see if they have any suggestions for books similar to the one you’re planning. Lit reviews are always helpful when it comes to putting together a setting.
The business of hunting and the suggested methods change depending on the animal in question. I will say that your hunters will probably not be regularly chasing big game (lots of effort) if they predominately stay in the same place. They’ll subsist mostly on small game (like rabbits, turkey, etc) and foraged vegetation. Again, I don’t know your setting well enough to know what those would be. However, I do suggest looking into bushcraft and survival/camping manuals to start getting a grasp of how one goes about finding food.
There are a lot of excellent resources available if you are willing to look.
When it comes to combat weapons knives and swords are meant for humans, they were not used for hunting. (The knife is used to skin and clean the game after it’s been killed or kill the trapped animal.) Swords are weapons specialized for warfare and for killing other humans, hunter gatherer societies don’t really have a use for them. You can take a machete or a kukri, which are tools not weapons but within the short sword range, and maybe find a use for them in the clearing vegetation/butchering animals stage.
The problem here is that swords, especially the longsword, require a fairly advanced development of metallurgy. You need someone to make the weapons and the ability to find/mine the necessary materials. You also need a society where metal (be it bronze or iron), even if crude, has become common and necessary to the society. These are usually societies that have transitioned from hunter/gatherer into agricultural. Agricultural societies need blacksmiths to develop better tools for farming, stonemasons for houses, etc.
If those resources are minimal, then they will go toward those items that the culture needs more like knives, spearheads, and other tools than a weapon they have little use for (a sword) when they have other weapons available like bows and spears which work just as well.
You said it yourself, the clans aren’t initially at war and later they “go to war with the weapons they hunt with.” As we’ve said in the past, “You do not go hunting with the weapons you take to war.”
That said, there’s a lot of room to play with some very interesting weapons, tactics, and techniques from a vast number of indigenous cultures across the world that have nothing to do with swords. There’s a vast and very rich cultural history of varying kinds of warfare among the Native American/First Nations tribes, the Zulu and other tribes throughout the continent of Africa that have massive varying differences depending on region and climate, and a number of indigenous groups in many countries in South East Asia with a long and interesting history.
The advice I give everyone for world building is this: you have to learn how to marry what you want with what you’ve made available through your setting. Weapons are primarily developed based on need and available resources. A society primarily based on hunting is more likely to develop better traps, better bows, and better spears. If they are migratory (with a lot of open space like plains or steppes) then they may domesticate animals like horses for easier travel over long distances. Their homes may be lighter, easier to break down and carry with them or they may need to stay in one place but travel great distances because game in their region is sparse.
A group in a jungle may develop a machete or a kukri to clear vines, use boats for travel because they have rivers instead of horses because an enclosed environment doesn’t favor them. Goats, Llamas, and donkeys/burros are common beasts of burden in regions with more mountainous terrain.
There are a thousand reasons why, but what is key is finding the set pattern of development for your setting. Not all your societies necessarily developed the same way. They may use different weapons or different variations, different tactics based entirely around dealing with different threats from different regions.
This is why looking at historical cultures and modern ones is so important. Once you develop an understanding of how other people adapted to their environment and the different ways they did even within the same region, then you can backtrack to your characters, look at the world they live in and come to a better realization of understanding what they do and why it is that way.