In this world, dinosaurs are wildlife that usually don't bother people, but people still want to make sure they're safe from the occasional man-eaters or gigantic herbivores that want to eat their crops. People don't need to kill the dinosaurs, they just want to live peacefully. What can they do to make their village as safe as possible?
Man-eating dinosaurs should be relatively easy to keep at bay. A tyrannosaurus is a little under 4 meters tall, so it should be possible to hold it back with a good wooden wall at about that height. The villagers should keep a bell to ring when one is spotted to that everyone can run back to the walled fort to hide. Some flaming arrows might help persuade it to leave.
I would also keep a few decoy cows ready to release in order to draw its attention away if it's cornering a villager. You could coat the cow in some oil or other unpleasant-tasting substance if you want to teach it not to look in the village for food. Or poison.
Herbivores, sadly, are a bit trickier to deal with, mostly because vegetables don't know how to run and hide inside the walled fort when one comes along. It's probably not practical to try to fence in all of the farmland either, as this is a lot of land. And those long necks are basically designed to reach over a fence and nab the goods anyway.
I would suggest growing root crops such as onions or carrots, which will not be as easy for a dinosaur to spot. I would also keep a team of mounted riders on constant watch over the fields, with bells and flaming arrows to scare away any herbivores that come along. This would be a pretty dangerous job, though, if they make the animal mad or attract the attention of a man-eater.
Large dinosaurs are like elephants. Very strong, but the one thing they can't do is jump. Their massive body weight increases with the cube of their size, meaning that large dinosaurs are at the limit of what their body can physically support. Trying to jump is impossible for them.
So forget about trying to build a strong wooden fence, build a ditch. That's how they contain elephants at the zoo and it works well enough:
As opposed to men, animals are much more reasonable. They don't stubbornly go in places where they experience discomfort.
Therefore walls, fires and smoke, topped with loud noises will be good dissuasive means.
Keeping food away to remove any rewards for facing the troubles will also help.
do what humans have always done, barriers and hunting.
Real farms used hedgerows. Real hedge row will stop a dinosaur, real hedgerows are made of earth, stone, woven fencing, shrubs and trees. they produce a rather solid barrier. They may just have to make them a little taller. it will actually be harder for large animals to get through them than small ones. Add a ditch as others have mentioned and it works even better. There is a wide range of making hedgerows but the goal is always the same to create a barrier to wildlife and domesticated animals. Remember these farmers already have to deal with a wide range of wildlife trying to eat their crops, including their own livestock.
If something does get through, farmers will go hunting, bows will kill most dinosaurs, especially if they add poisons. Really these animals are going to be hunted anyway, large amounts of meat are a very desirable target. Humans hunted mammoths to extinction before we used metal. the more dangerous the dinosaur the more likely humans already hunted them to extinction at least locally. humans with children are not very tolerant of dangerous creatures, and apex predators are always vulnerable to overhunting. It is even easier to drive them away, slings, fire, and arrows will easily drive away dinosaurs, animals are not movie monsters, if they get hurt they leave.
for tougher dinos you get creative. One of the simple ways to hunt large animals is a technique used by elephant poachers, hammer a large metal spike into a board, and hide it in leaves or grass on a trail. the weight of the animal does the damage for you. for a T-rex spikes, pits, and triplines will work well. for armored dinos use fire. there is very little a group of prepared humans cannot kill.also keep in mind a large dinosaur could likely feed an entire village possibly for days, so they have a strong incentive to hunt them.
Of course they may also domesticate some dinosaurs, if you have a large number of species that chances that at least one will be domesticable is decent.
Search for elephant village fence africa park
We are currently testing beehive fences in selected locations and have found that it very successfully deters elephants. – The Wildlife Connection
The dogs are bred to move livestock. In this case, the fearless canines are trained to handle massive elephants. They charge and nip at the elephants' feet and trunks. The elephants have such respect for the dogs that even if they hear a handler say the name Major or Zeta, they take notice.
Having dogs to chase off dinosaurs might be doable. The big carnivores are probably not quick enough to catch a dog. The small ones might but in addition to the silent scary sheepdog types you will have some small dogs who are master barkers, so the people will hear something is up.
Since this is a fantasy you could riff on the dogs with some more dramatic creature. One of the Jurassic Park movies had something like this - Velociraptors that were semi-tame or at least willing to cooperate with humans to take on much larger animals. A pack of dinos in residence could chase off intruders of all kinds.
The same thing villagers did to protect themselves against (human/animal) threats in history: nothing (though this is dependant on the wealth/size of the village).
Villages tended to be small and poor. They wouldn't be able to build a large and costly defense such as a wall or ditch or even have dedicated guards. This is why they are susceptible to attacks from bandits and the like.
In this world, dinosaurs are wildlife that usually don't bother people
So people aren't likely to invest much in defences. They may fall back on the old approach of surrounding themselves with thornbushes. If there's a known threat in the area they may supplement those with fires stoked by people keeping 2-hour watches, and they may try to hunt the individual down. But for the most part they'll get on with their lives.
So... I think it should be noted that in even a reasonably populated area, dinosaurs would never get that big. Sauropods (like the Apatosaurus) took ten years to reach full size. By the time that happened, they would be noticeable and then hunted for the massive amount of meat it would provide. Tyrannosaurs spent most of their early years smaller than economy-sized car. Neither one of these would really need to be "defended against."
You get a little more complicated when you start getting to the mid-sized predators (such as the Deinonychus) but even with them there isn't that much danger. After all, we have dangerous, predatory animals in the woods now. While wolf and tiger attacks are something that do happen, they're very, very rare.
Eating them, using their skin and bones as raw materials for many things and domesticating the small, smart, social ones. Man is a deadly hunter that, before civilization, alredy hunted megafauna many times its size. With medieval iron, pikes, big horses to ride, the dinos stand no chance.
For bigger dinosaurs their size would be their biggest enemy, just make a ditch or any kind of trap that would make a dinosaur fall. Fallen t-rex is almost always dead t-rex because of square-cube law, and they werent even that big!
Smaller dinosaurs could be treaten as any other similar-size mammal carnivores.
Medieval people could make and operate some pretty serious artillery; heavy crossbows, scorpions, ballistae, and the like. Dinosaurs are tough but their hearts and lungs are still just flesh. Their skulls are just bone. Crossbows and scorpions that can get through the plate armor a knight wears can also probably get through the cartilage between ribs or the skull. So whatever defenses these settlements have to use against people will be just as effective against dinosaurs.
During the day with human activity in the village and fields that should be enough to deter most herbivores, more determined herbivores could be kept back using ditches or trained animals such as dogs. Large carnivores should be spotted early, creating a buffer zone of cleared land outside of the village and fields would help in this regard. On spotting a large carnivore an alarm should be signaled to recall civilians into the village while a militia goes out to defend using bows and pikes.
The hardest part would be protecting the crops at night when there is little to no human activity to keep herbivores away. I think a ring of braziers spaced around the village and its fields to be lit each night would go a long way to deterring herbivores, you could also add a night watch to patrol if the village is large enough.
A cave in thick stone, multiple entrances/exists of course. Even if you have to chisel an entrance.
Big enough for humans to enter, but small enough to keep the big ones away.
Also, if you can get the dino to force its head in, your in the prefect position to kill it with arrows, and other ranged weapons.
100 feet in erect a wall to keep the smaller ones out.
If your really clever you can install a guillotine in the cave.
Medium/Big sticks its head to far in .... "off with its head"
You would need high fence that are probably 50 feet in front from your crops so sticking there head over high wall nets them nothing.
Same way a village would try to keep an army away
For a large town or city, Build walls, dig moats and have a draw bridge to allow and deny access.
For villages, build wood fences with sharp edges on the top and build watchtowers with archers to allow ranged attacks to dissuade dinos. Archers could also soak the tip of the arrows with oil and light it on fire before firing them. Horse archers surrounding the dino maybe a good idea to confuse it too by hit and run in every direction.
If the attack persist, maybe you can distract the dinos by release some horses with raw animal meat tied to its tail and let run away from the villages. Train every able bodied villagers to handle spears and archery when they are not working.
There is also an idea of a tribute every time the dinos are out hunting. Measure the time between each dino species visit and prepare some cows just before the next visits in a general area near the habitat of the dinos that are reasonably far from the village
The situation is prevented from the outset, and can never develop into regular raids.
Predators learn to fear the smell of humans, except for the occasional Jeuvanile (who quickly learns a harsh lesson if it escapes with its life). Predator species develop a major fear of humans and will not approach.
The biggest threat is not massive predators (t-rex) but man sized predators who are desperate (very hungry pack of velocoraptors or a lone-wolf utaraptor), or hyper patient ambush predators (e.g. crocodiles).
Even if the creature is a totally new discovery within living memory, and you're dealing with a primitive tribe who has just arrived, it doesn't take many attacks before the creature is tracked down and pre-emptively killed. Within one or two generations of the predator, an extreme fear of humans develops.
Giant herd-dwelling herbivores are a totally different story. Assuming your medieval society has enough un-tapped land that brontosauruses are not forced into close proximity humans, the occasional rare mass migration will be met with fire, arrows, spears, rocks, noise, etc.
Herds whose annual migration patterns intersect with humans are quickly wiped out.
As others pointed out, dealing with large dinos is not a problem; mankind has hunted and killed the largest land and sea and air animals it has met using tools that were much more primitive than available in most European/Asian feudal villages.
The real problems are:
- Stampedes. When you have a bunch of animals larger than delivery vans with brains of the size of coffee cups with only one thing in their mind -- get away from something really fast -- you do not want to be on their way. At times even fire may not stop them (imagine they are running from a forest fire/volcano/flood). There are recorded events (I do need to find them) when stampedes met their demises falling off cliffs and whatever because they were in herdthink mode.
- (really 1.1.) Controlled stampedes. What if your enemies set fire on some of the members of a herd and, well, herd them your way?
- Smaller, opportunistic animals more adapted to "silent hunting." You know, how tigers and foxes and snakes and chupacabras sneak into a farm and kill infant and elderly animals/humans who fell asleep watching "Late Night with the Black Knight." These animals are more adapted to "living" with humans by understanding their habits (ex: wolves seem to sense when someone is armed because of the attitude of said person, implying confidence or not).
I personally expect those smaller predator dinosaurs to be more adaptable than the dump truck sized ones. Those raptor sized ones have larger brains relatively speaking than the large ones. Look into how complex a group of crows are. For instance, when they (as a group) eat they leave spotters to warn the others of impending attacks.
Now you can argue that as soon as a family comes and says their baby is gone a mob will hunt down the predator. Well, not really. Unless your family was high up in the totem pole, you just accept that as a fact of life. Creating a posse meant other important tasks were done done, and people had to work all the time just to stay alive. For most of the human history people did not have the attitude that one death was one too many some societies have today. Not every child became an adult. Human life was cheap, and that was the case during the medieval times.
Theory answer: If human existed when dinosaurs lived on earth, humans would be bigger as well just like dinosaurs/trees/insects were at that time. Air-pressure and science made that body could carry more weight than today.
Look at today ants, that can carry its own weight several times, where their scale in compare to air-pressure/atmospheric pressure make their body be able to carry a certain weight. If ants were at human size of today, they would not be as strong.