Origin of Sanguivory (Vampire Bats):
The Dracula Connection to a Young Earth
| Author: John Woodmorappe Subject: Biology Date: 1/1/1995 |
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Despite the folklore about bats drinking the blood of sleeping humans, there are only three genera of bats that actually subsist on blood, in contrast to many hundreds of other genera that don’t [1]. Large mammals are apparently the preferred targets of vampire bats, although they will also drink the blood of smaller animals if necessary. The wound by the vampire bat is not usually severe, and often does not even awaken the wounded animal or person. Also, the volume of blood loss is usually small. However, there is always the danger of infection and the spread of rabies (hydrophobia).
Is it possible that vampire bats have acquired their disgusting habit of craving and drinking blood in only a few thousand years since the Fall? Some scientists have suggested that the vampire bat developed its blood-sucking practice while it was an insect-eater, as most bats are. It would pick off the insects on a vertebrate and, when it accidentally wounded it, would also drink its blood. Eventually, it switched to exclusively drinking blood.
The next question then is if this process could occur rapidly. One way to approach this question is to consider whether or not any other creature is apparently in the process of switching to a blood-centered diet. The answer appears to be in the affirmative. One of Darwin’s finches has a sub-population with an unusual habit. Instead of eating insects, it attacks other birds and drinks their blood [2]. The fact that it occurs in such a small population of finches indicates that this behavior can easily arise among typically non-blood desiring creatures.
From this, we can envision the following possible scenario for the origins of blood craving and eating (sanguivory) in vampire bats. Bats were originally created primarily fruit eating and/or insect eating. Most bats today are insect eaters. (The death of insects arguably need not be death in the Biblical sense, because invertebrates are not conscious and perceptive creatures in the same way that vertebrates are.) After the Fall, living creatures began to eat various things outside of their previous domain. Analogous to these unusual finches we observe today, vampire bats may have begun drinking blood if they accidentally wounded their host. Eventually they acquired a preference for blood, which then became their exclusive diet.
An important factor in this scenario, whether approached from an evolutionary or Creationist viewpoint, is the fact that the family that contains vampire bats (Phyllostomatidae) has, on the whole, certain pre-adaptations that would have allowed blood drinking to arise in vampire bats. Fenton points out that there are certain anatomical features these bats have that others don’t, at least to such an extent. For instance, these bats have specialized sharp teeth. It would have taken only a small modification to have them used for piercing flesh. The structure of the tongue is pre-adapted to lapping blood.
This helps explain why blood eating arose only among a few South American bats, and not on any other continent. The bats on other continents had too much morphological change to overcome in contrast to the Phyllostomidae. This fact fits better with the young earth creationist time frame than an evolutionary one. Had millions of years been available, many bats should have had the time to develop a sanguivory habit. But with just thousands of years available, only those bats which already possessed anatomical features consistent with blood sucking actually switched to it.
NOTES
[1]. Fenton, M.B., Wounds and the Origin of Blood-Feeding in Bats, Biological Journal of the Linnean Society, 47:161-171, 1992
[2]. Bowman, R. I., and Billeb, S. L., Blood-Eating in a Galapagos Finch, The Living Bird, 4:29-44, 1965.
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