Well…. You made me spend a good hour researching this. There are only two species of beaver. The American beaver (Castor canadensis) And the Eurasian beavers (Castor fiber). Both are considered territorial and aggressive. A fisherman in Belarus was bitten to death by a beaver, and all he was doing was trying to take its picture. There have also been reports of children being mauled by beavers in the United States so it’s hard to call. I’d say the Eurasian Beaver is probably the most dangerous since it is larger by like 10lbs on average. Most beaver attacks are rabies related, provoked, or caused by disorientation. Either way, stay away from beavers.