Similar to Snakes from the Shipwrecked DLC, Vipers are nocturnal creatures, and unless they are provoked by chopping down a Rainforest Tree or flipping the stone slabs, they will not be active until Dusk and through Night. If any Vipers are attacked, all other Vipers in the vicinity will join in the battle to attack their aggressor. If the player runs far enough away, the Vipers will give up, and fall asleep until another creature or the player walks near. Vipers will actively pick fights with all other creatures (except their own kind), hostile or not. Vipers will try to eat Meat and Eggs that are left on the ground.
- Vipers take 1 blasts to be frozen with an Ice Staff and takes 1 Sleep Dart to be put to sleep.
- Vipers may be kited by dodging their attack and then attacking them 3 times which kills them before they can hit the player, as long as a weapon at least as strong as a Spear is used.
- Vipers can be hit once before they attack and still miss their target. This is very useful for dealing with groups of Vipers.
- According to Wickerbottom, vipers resemble a breed of Agkistrodon, which is a genus of the Viperidae family. Despite all members of this family are venomous, vipers seem to be non-poisonous in the game. Vipers have the ability to swim and have a forked tail. However, no snakes with a forked tail exist in real life.