We land in Mexico City to continue filming the documentary. First up is a main dish whose very name evokes a mixture of fear and fascination; an animal that in many human societies is regarded as half fantasy, half real: the vampire.
Vampires are small bats from the tropics of the Americas that resemble many others of the world’s 1,200 species of bat. Nevertheless, they have a well-known specialization: they are bloodsuckers or hemovores, that is, they feed exclusively on the blood of other animals.
We meet up with the members of the Comité de Fomento y Salud Animal del Estado de Puebla (Puebla State Committee for Improving Animal Health) and they take us to the rural areas where conflicts with vampires occur and where they do most of their work. We are lucky enough to watch how the vampires suck blood – with surprising skill – from animals that are hundreds of times bigger than they are.
The vets from the Comité have carefully set up the show and, once night has fallen and after an interminable wait made worse by our great expectations, we finally get a chance to see the vampires in action. They approach their prey by hopping agilely along the ground like frogs, their infrared vision enabling them to detect the warmest part of their victims, which is where the blood is nearest the surface. From here on, a biochemical war begins that seems like something straight out of a science fiction tale: first they lick the chosen point of attack so that the anaesthetic in their saliva deadens the animal’s skin; then they make a small insertion with their razor-sharp teeth – which the animal doesn’t even notice! – and begin to feed on the blood, which continues to flow thanks to the natural anticoagulants in the bats’ saliva. We watch as the vampires attack the feet of a horse; the bats fly off to avoid any problems every time the horse makes a movement, but then return immediately to their feasts. The whole show lasts half an hour and ends up with a sated bat, with its daily nutritional needs attended to, and a horse with a small, apparently innocuous wound on one foot.
There are three species of vampire, but only one, the common vampire Desmodus rotundus, actually feeds on mammal blood. The seriousness of their attacks are not due to the wounds they inflict on cattle but rather the infections and disease they can transmit from one victim to another. One such disease is rabies, the disease that cattle farmers and local authorities alike fear the most, and which bats can pass on with fatal consequences for their victims.