Make sure no other Castoroides are around then bola it and shoot it with tranqs until it knocks out. Make sure you bring loads of bio toxin, because their torpor drains fast. I used this method and tamed one at level 42
The way to tame these guys is to run up to one of their dams and then open it and then immediately close it (you don’t have to take anything from it, opening the dam will immediately aggravate all and any nearby beavers). Once this step has been done, you must bola the beaver (assuming only one tries to fight). I actually made a hearty mistake and bolaed the first one that came whereas I should’ve killed the second first (I was making a video, the second one got killed). Once the beaver is bolaed and separated from its mates, go behind it where it can’t hit you and hit it with a bat until you knock it out, but before doing any of these either kill jellyfish for bio-toxin for torpor (the beaver’s torpor will drain quickly) or farm a bunch of narcoberries in preparation. These guys are herbivores so you should also farm other berries besides narcoberries, or gather from the nearby forests. Keep in mind that beavers EXTREMELY slow eaters when knocked out, so patience is your weapon here.
Well I use this trick to tame all dinos and it works 98% of the times . Okay first tame a tapejara make a saddle and ride it when you see one of those guys go a little high and change your seat keep in mind your tapejara will automatically land on the ground if you change your seat to close to the ground . And I think you know what to do next , just tranq them and berries or vegetables feed them and keeping necrotic or bio toxin or else you just wasted all your effort and start celebrating when you tame it rather than celebrating when they are sleep cuz they wake up fast
Where ever it says "how many narcotics needed" on this app is a lie. You almost always need way more than is recommended on here. So do not plan your tames around how many narcotics this app recommends for it.
So try and knock it out (this might take a while) feed it berries. But if you don’t bring any narcotics it will wake up. (This creature is in packs. So try to knock one and kill one but the downside is this creatures torpor will drain faster than any other. Be careful)!