Can you tell me why in the Pampas, ay and elsewhere, there are bats that come at night and open the veins of cattle and horses and suck dry their veins; how in some islands of the Western seas there are bats which hang on the trees all day, and those who have seen describe as like giant nuts or pods, and that when the sailors sleep on the deck, because that it is hot, flit down on them, and then—and then in the morning are found dead men, white as even Miss Lucy was?”
“Good God, Professor!” I said, starting up. “Do you mean to tell me that Lucy was bitten by such a bat; and that such a thing is here in London in the nineteenth century?”
"Vampire bats" are native to the Americas, and tales of them began to filter back following the European invasion of the New World, where they form a relatively late addition to the vampire lore. Bram Stoker expressly ties them into the figure of Dracula in his eponymous novel, with the Count taking the form of a great bat and/or having influence on bats, and was notably absent from earlier works like J. Sheridan le Fanu's "Carmilla" (1872), "Varney, The Vampire" (1845-1847), or John William Polidori's "The Vampyre" (1819).
The similarity was continued by contemporary writers and researchers such as Montague Summers, who noted in The Vampire: His Kith and Kin (1928):
Just as we have the parasitic men and women, so have we the parasitic plants, and at this point there imposes itself upon us some mention of the animal which directly derives a name from habits which exactly resemble those of the Slavonic Vampire--the Vampire Bat. There has been much exaggeration in the accounts which travellers have given of these bats and many of the details would seem to have been very inaccurately observed by earlier inquirers. The Encyclopædia Britannica says[77] that there are only two species of blood-sucking bats known--Desmodus rufus and Diphylla ecaudata. These inhabit the tropical and part of the sub-tropical regions of the New World, and are restricted to South and Central America. Their attacks on men and other warm-blooded animals were noticed by very early writers. Thus Peter Martyr (Anghiera)
who wrote soon after the conquest of South America, says that in the Isthmus of Darien there were bats which sucked the blood of men and cattle when asleep to such a degree as even to kill them. Condamine in the eighteenth century remarks that at Borja, Ecuador, and in other districts they had wholly destroyed the cattle introduced by the missionaries. Sir Robert Schomburgh relates that at Wicki, on the river Berlice, no fowls could be kept on account of the ravages of these creatures, which attacked their combs making them appear white from loss of blood.
By this point, the idea of the predatory vampire bat being connected with the supernatural vampire was relative well-established in literature, appearing in stories like "Four Wooden Stakes" (1925) by Victor Roman, and would go on to be a staple of pulp and horror fiction.
What really cemented the idea in the mind of the public was the 1931 film adaptation of Dracula starring Bela Lugosi. The stage play had already added an operatic cape to the Count's costume, but the film reached a wider audience, and the special effects and increasingly the marketing materials for Dracula (1931), its sequels, and material inspired by the book, play, and film began to feature a bat-motif much more prominently, such as the famous Oct 1933 cover of Weird Tales (illustrating "The Vampire Master" by Hugh Davidson). Actual transformations could also appear on film, such as the transition in Mark of the Vampire (1935).