In the previous post we saw that vampire bats were more diverse and more widespread during the Pleistocene than are they today. Two things stand out (to me) as being particularly interesting; firstly, that some of these vampires seem to have differed in morphology, and therefore presumably in ecology and behaviour, from the living vampire species; and secondly, that some of these vampires survived until very, very recently. Here, we look at these two areas in more detail…
What species were these fossil vampires feeding from? Of the three living vampires, both the Hairy-legged vampire Diphylla ecaudata and White-winged vampire Diaemus youngi mostly prey on birds. However, the Common vampire Desmodus rotundus mostly preys on mammals, and because the fossil species are members of the genus Desmodus, it is reasonable to assume that they, also, mostly fed on mammals. A few vampire bat fossils are preserved associated with large mammals. A fossil Common vampire from a Brazilian cave, radiometrically dated to about 12,000 years ago, was discovered adhering to the underside of a coprolite produced by the sloth Nothrotherium (Czaplewski & Cartell 1998) and D. stocki fossils from Florida are preserved in the same caves as ground sloths. A skull belonging to the giant vampire D. draculae was preserved in association with a skull of the extinct horse Equus neogeus. None of these associations demonstrate the predatory preference of the vampire species concerned, but they are at the very least highly suggestive. The idea that some of these bats may have fed on giant sloths is likely and entirely acceptable, and one published life restoration – a drawing by Randy Babb, in Brown (1994) – depicts a D. stocki feeding on a nothrotheriid sloth.
Intriguingly, the morphology of some of these vampires suggests that they differed in ecology and behaviour from the living vampire species. Both D. archaeodaptes and the Cuban species D. puntajudensis seems to have had far more freedom of movement in their jaw joint that the Common vampire, a feature suggesting that they somehow differed in how they procured and/or bit their prey (Morgan 1991, Suarez 2005). The robust hindlimb bones of D. puntajudensis and D. stocki also suggest that their style of terrestrial locomotion differed from that of the Common vampire, though exactly how it differed remains unknown. The large size of D. stocki, D. draculae and the Argentinean giant form of course indicate that they fed on larger prey than living vampires and, as noted, these fossil bats are sometimes found associated with ground sloths. In the adjacent illustration I’ve shown D. stocki feeding from the leg of a teratorn. I knocked the drawing up myself because I’m bored with using pictures of living vampires.
Many fossil vampire records occur outside of the 10 degree C minimum isotherm that, today, marks the distributional limit for vampire bats. Rather than these records indicating cold-tolerance among the extinct species, it is more likely that the respective regions were warmer in the past than they are now, and indeed the associated fauna and other data shows that this was the case. Even so however, some of these records – such as occurrences of D. stocki in Florida – show that these bats inhabited warm temperate climates, and were not only restricted to tropical conditions. Some of the extinct vampires may also have been less reliant on the extremely high humidity that is required by living vampires, as some of the caves where their remains are found don’t appear to have been especially humid.
Also of particular interest is the fact that some of these vampires survived until very, very recently. D. puntajudensis survived into the Holocene, and D. stocki even survived into historical times and was still alive 3000 years ago on San Miguel Island off southern California (Ray et al. 1988). Most remarkable of all is D. draculae. The original Venezuelan discoveries of this species might be as young as 10,000 years old and were discovered associated with the bones of extant species. Even better, the large D. draculae-like vampire from Argentina has been dated to an unbelievable 300 years ago (Pardinas & Tonni 2000), so this unnamed species was alive in c. 1700. The dates are so incredibly recent that several mammalogists have noted the possibility that D. draculae and similar forms might still survive, and await discovery (Ray et al. 1988, Trajano & de Vivo 1991). Indeed Trajano & de Vivo (1991) noted rumours from local people about particularly large Brazilian vampires that sometimes attacked their horses and cattle [adjacent pics of leaping vampire from here, as is the picture of the Camazotz statue at the top].
Various myths, legends and stories from Mexico and Central America describe large bats that, some researchers suggest, might be further references to these big vampires. The best known of these is Camazotz (also sometimes spelt Camalzotz), a bat-headed monster who (in some Mayan tales) inhabited the cave Zotzilaha in what is now Guatemala. Camazotz apparently translates as ‘death bat’ or ‘snatch bat’, and Gable (1997) noted that stories of bat-like demons also persisted in the cultures of Chiapas in Mexico and elsewhere. While Camazotz has conventionally been associated with the Common vampire, it is conceivable that big species like D. draculae were the inspiration for these tales. The Brazilian Muras Indians have tales of an enormous blood-eating bat called Caoera that is as large as a vulture, and again it is tempting to think that this just might be an exaggerated reference to a genuine giant vampire.
Also of interest are the various modern tales that tell of how people in Argentina and elsewhere have been attacked by immense vampire bats (go here to see examples). It is doubtful if these stories really have any truth in them: if they do then the bats they report are considerably larger even than D. draculae, and differ significantly from real vampires in not attacking stealthily.
And that will do for now. There is still one major area concerning vampires that I have yet to address, and this is how blood-feeding actually evolved within the group. This, and much more, due to come soon…
Refs – -
Brown, D. E. 1994. Vampiro: the Vampire Bat in Fact and Fantasy. High-Lonesome Books (Silver City, New Mexico).
Czaplewski, N. J. & Cartelle, C. 1998. Pleistocene bats from cave deposits in Bahia, Brazil. Journal of Mammalogy 79, 784-803.
Gable, A. 1997. Two possible cryptids from Precolumbian Mesoamerica. The Cryptozoology Review 2 (1), 17-25.
Morgan, G. S. 1991. Neotropical Chiroptera from the Pliocene and Pleistocene of Florida. Bulletin of the American Museum of Natural History 206, 176-213.
Pardinas, U. F. J. & Tonni, E. P. 2000. A giant vampire (Mammalia, Chiroptera) in the Late Holocene from the Argentinean pampas: paleoenvironmental significance. Palaeogeography, Palaeoclimatology, Palaeoecology 160, 213-221.
Ray, C. E., Linares, O. J. & Morgan, G. S. 1988. Palaeontology. In Greenhall, A. M. & Schmidt, U. (eds) Natural History of Vampire Bats. CRC Press (Boca Raton, Florida), pp. 19-30.
Suarez, W. 2005. Taxonomic status of the Cuban vampire bat (Chiroptera: Phyllostomidae: Desmodontinae: Desmodus). Caribbean Journal of Science 41, 761-767.
Trajano, E. & de Vivo, M. 1991. Desmodus draculae Morgan, Linares, and Ray, 1988, reported for southeastern Brasil, with paleoecological comments (Phyllostomidae, Desmodontinae). Mammalia 55, 456-460.