Dangerous biters are venomous creatures that can cause serious harm to humans. ADDERS, which have six letters, are a type of venomous snake found in Europe, Asia, and Africa. Asps, with four letters, are a type of venomous snake found in the Middle East and Africa. Tsetses, with seven letters, are a type of fly found in Africa that can deliver a painful bite. All of these creatures are considered dangerous biters and should be avoided.