Why are Vampire bats dangerous?

Vampire bats are dangerous because they carry rabies and other diseases and infect their victims as they suck the blood which is their only food.

Vampire bats (Desmodontidae) are found only in South and Central America. They have extremely sharp teeth and pierce the skin of their prey so gently that the victim does not awaken. Blood is drawn into the mouth by the almost tubular tongue and the vampire bat’s whole digestive system is specially adapted for his diet of blood.