The Common Vampire Bat

 

            The Common Vampire Bat, or Desmodus Rotundus, is a member of the Phyllostomidae family. The Phyllostomidae family consists of 147 species of bats in 51 genera. The 147 species exhibit much greater diversity than any other family of bats. There are six subfamilies within this family. The Vampire Bat is part of the Desmodontinae subfamily. (Altringham) Vampire Bats have existed for six to eight million years. Fossil records show that there were more species of Desmodontinae, but they all died out. There are three theories as to the origin of the Vampire Bat. The first is that they evolved from frugivore phyllostomids. It can be conceived that the teeth of Vampire Bats evolved from fruit eating bats. The second theory is that they evolved from insectivorous bats. It is thought that they ate ticks and other blood sucking parasites off animals and eventually just started eating the blood. The third idea is that they evolved form leaf-nosed bats by eating burrowing insects like the screwworm that burrows into animals skin. They then transitioned from licking the outside of the wounds to eating the blood. The last theory explains why this adaptation is found in the New World. (Tomlinson)

The Vampire Bat is found all the way from Northern Mexico and the southern United States to Chile, Argentina, and Uruguay. It is also found on the islands of Margarita and Trinidad. This species inhabits both arid and humid regions. In a 1976 study, Handley collected 57 percent of his specimens from forests and the other 43 percent from yards, pastures, and other open habitats. They reside in all types of fixtures. They usually are found in caves but also occupy hollow trees, wells, mine shafts, and abandoned buildings. Desmodus Rotundus may roost alone or in colonies of up to two thousand individuals. Most of the colonies contain between 20 to 100 bats. When there are more than 50 individuals, there are usually social units of 8 to 20 that divide the colony up into parts. (Nowak)

            The Vampire Bat is of average size for a bat. The head and body length of Desmodus Rotundus is around 70 to 90 millimeters, having no tail. The forearm length is 50 to 63 millimeters. An adult vampire bat can weigh anywhere from 15 to 50 grams. (Nowak)

            The Common Vampire Batπs upper parts are dark grayish brown and the underparts are paler. (Nowak) Unlike all other Phyllostomidaes, the Vampire bat does not have the blade-like noseleaf along with simple, long ears. (Altringham) Desmodus Rotundus distinguishes itself from the other true vampire bats by its pointed ears, longer thumb, naked interfemoral membrane, and dental features. Desmodus Rotundus has only 20 teeth. The largest teeth are the two chisel-like upper incisors and the two upper canines. (Nowak)

            The common vampire bat varies greatly in its means of mobility as compared to other non-blood-sucking bats. Of all the species of bats in the world, Desmodus Rotundus is the only one that can maneuver as well on the ground as it can in the air. They spend a lot of time walking around on all fours, resting both on their legs and on the digit projecting from their wings. Unlike other bats, it is able to launch itself from the ground into flight. A vampire bat is able to launch itself from the ground into fight in a mere .03 seconds. Desmodus Rotundus extends its forelimbs and pushes itself off the ground with its large pectoral muscles. The Vampire Bat needs this ability as its prey could easily crush it. If it is feeding from a cowπs foot and the cow takes a step back it must be able to leap into flight to evade the cow extremely fast. It is also useful when they are on the ground and a predator approaches. (Vaulting Vampires) Of all three vampire bats, Desmodus Rotundus has the strongest legs. It also lacks the tail membrane that all other bats have between their legs to assist in flight. (Bloodthirsty)

            The Vampire Bat got its name from what it eats: blood. Desmodus Rotundus differs from the other two species of vampire bats by that it feeds off of mammalian blood, while the other two prefer avian blood. (Tomlinson) The Common Vampire Batπs teeth are so sharp that it can remove a piece of skin without the prey even feeling it. They have heat-sensitive noses that allow them to find a spot on the body where it can draw blood the easiest. They can eat up to three-fifths of their body weight in blood in one sitting. Unlike common myth, they do not suck the blood; they lap it with their tongue. This enables the bat to draw the blood fastest. Their tongue has grooves on it that brings the blood into their mouth by capillary action. A hole normally made in human skin should bleed for no more than 10 minutes and shed less than one gram of blood. The common vampire bat has an anti-coagulant in its bite, known as plasminogen activator that allows the blood to flow freely and subverts the clotting mechanism. (Sieveking) Plasminogen activator, or Bat-PA holds great potential in treating stroke victims. A study showed that Bat-PA is 200 times more selective at removing blood clots in stroke victims than current medications. It also does not promote the killing of brain cells as do the current medications. (Cheater)

Researchers? have demonstrated that vampire bats may have lost a special adaptation that tells them not to eat something that makes them sick. Because they only eat blood they do not encounter any toxins that make them sick so they will eat something no matter what it is. In the study, they placed citric acid in blood to give it a distinct taste. The researchers then made the bats vomit with an injection. All other bats stayed away from the taste that made them sick but the vampire back kept going back for more. (S.M.)

            Vampire Bats also show a keen sense of selflessness. Within a colony of females, if a member has not gotten enough blood to survive, one who has eaten enough to stay healthy will regurgitate the blood into the mouth of the sick female to save it. This behavior is reciprocal between all of the bats within a colony. They also feed their young in the same fashion before they are old enough to hunt. (Altringham)

            The Common Vampire Bat has an asynchronous, continual reproductive cycle. Each bat though only produces two litters of single young each year. (Altringham) There are peak periods of birth in some areas. There have been recorded gestation periods of anywhere from 200 to 215 days. The newborns are well developed and are born with their eyes open. The oldest bat captured was nineteen and a half years old. (Nowak)

            The Common Vampire Bat has been given a bad name because of its connection to rabies. The Common Vampire Bat is less of a threat to humans than it is to the livestock that it feeds on. It is estimated that Desmodus Rotundus infect up to 100,000 cattle each year with rabies and cause about $40 million in damages to the livestock industry. (Nowak) The Common Vampire Bat is thriving as a result of the steady diet it has from livestock.

            Desmodus Rotundus is a very interesting species of the Phyllostomidae family. They are very different from many of the other species and are one of the most unique bats because of their feeding habits. Much mystery and misinformation exists around this species of bat. The Common Vampire Bat will continue to thrive in the New World because of its readily available food source. Modern medicine may benefit from the further study of these creatures.

Bibliography

∑           Altringham, John D. Bats: Biology and Behaviour. New York: Oxford University Press Inc., 1996.

 

∑           ≥Bloodthirsty.≤ Economist 12 Oct. 1996. EbscoHost. 22 Feb. 2004 <http://web12.epnet.com/citation.asp?tb=1&_ug=dbs+aph+sid+3799CDB4%2D78FA%2D419E%2DA173%2D2DE11BDE0798%40sessionmgr6+D2C5&_us=dstb+ES+fh+0+hd+0+hs+0+or+Date+ri+KAAACBUB00033025+sl+%2D1+sm+ES+ss+SO+B617&_uso=db%5B0+%2Daph+hd+0+op%5B2+%2DAnd+op%5B1+%2DAnd+op%5B0+%2D+st%5B2+%2D+st%5B1+%2D+st%5B0+%2Dvampire++bat+tg%5B2+%2D+tg%5B1+%2D+tg%5B0+%2D+416C&fn=31&rn=32>.

 

∑           Cheater, Mark. ≥Care for a Bite?≤ National Wildlife May 2003. EbscoHost. 22 Feb. 2004. <http://web12.epnet.com/citation.asp?tb=1&_ug=dbs+aph+sid+3799CDB4%2D78FA%2D419E%2DA173%2D2DE11BDE0798%40sessionmgr6+D2C5&_us=dstb+ES+fh+0+hd+0+hs+0+or+Date+ri+KAAACBUB00033025+sl+%2D1+sm+ES+ss+SO+B617&_uso=db%5B0+%2Daph+hd+0+op%5B2+%2DAnd+op%5B1+%2DAnd+op%5B0+%2D+st%5B2+%2D+st%5B1+%2D+st%5B0+%2Dvampire++bat+tg%5B2+%2D+tg%5B1+%2D+tg%5B0+%2D+416C&fn=1&rn=9>.

 

∑           Fields, Helen. ≥Vampire Bats Arenπt Fussy Eaters.≤ Science Now 28 Feb. 2003. EbscoHost. 22 Feb. 2004. <http://web12.epnet.com/citation.asp?tb=1&_ug=dbs+aph+sid+3799CDB4%2D78FA%2D419E%2DA173%2D2DE11BDE0798%40sessionmgr6+D2C5&_us=dstb+ES+fh+0+hd+0+hs+0+or+Date+ri+KAAACBUB00033025+sl+%2D1+sm+ES+ss+SO+B617&_uso=db%5B0+%2Daph+hd+0+op%5B2+%2DAnd+op%5B1+%2DAnd+op%5B0+%2D+st%5B2+%2D+st%5B1+%2D+st%5B0+%2Dvampire++bat+tg%5B2+%2D+tg%5B1+%2D+tg%5B0+%2D+416C&fn=11&rn=11>.

 

∑           Geier, Thom. ≥Dracula Drug.≤ U.S. News and World Report 22 May 1995. EbscoHost. 22 Feb. 2004. <http://web12.epnet.com/citation.asp?tb=1&_ug=dbs+aph+sid+3799CDB4%2D78FA%2D419E%2DA173%2D2DE11BDE0798%40sessionmgr6+D2C5&_us=dstb+ES+fh+0+hd+0+hs+0+or+Date+ri+KAAACBUB00033025+sl+%2D1+sm+ES+ss+SO+B617&_uso=db%5B0+%2Daph+hd+0+op%5B2+%2DAnd+op%5B1+%2DAnd+op%5B0+%2D+st%5B2+%2D+st%5B1+%2D+st%5B0+%2Dvampire++bat+tg%5B2+%2D+tg%5B1+%2D+tg%5B0+%2D+416C&fn=31&rn=36>.

 

∑           Henry, Daniel Q. ≥Vampire Bat Saliva May Offer Treatment for Strokes.≤ AP World stream 7 Feb. 2004. Lexis Nexis. 22 Feb. 2004. <http://web.lexis-nexis.com/universe/document?_m=5d8d32705b81fffbb12d06f4aec3ecc4&_docnum=1&wchp=dGLbVlb-zSkVA&_md5=3ec4e9006e54ec2edf9752ff97dcb124>.

 

∑           Tomlinson, Denis. Natural History of the Vampire Bat. Organization for Bat Conversation. 22 Feb. 2004 <http://www.batconservation.org/content/meetourbats/vampire.htm>.

 

∑           Nowak, Ronald M. Walkerπs Bats of the World. Baltimore: The Johns Hopkins University Press, 1994.

 

∑           Sievking, Paul. ≥Forteana.≤ New Statesman and Society 30 June 1995. EbscoHost. 22 Feb. 2004. <http://web12.epnet.com/citation.asp?tb=1&_ug=dbs+aph+sid+3799CDB4%2D78FA%2D419E%2DA173%2D2DE11BDE0798%40sessionmgr6+D2C5&_us=dstb+ES+fh+0+hd+0+hs+0+or+Date+ri+KAAACBUB00033025+sl+%2D1+sm+ES+ss+SO+B617&_uso=db%5B0+%2Daph+hd+0+op%5B2+%2DAnd+op%5B1+%2DAnd+op%5B0+%2D+st%5B2+%2D+st%5B1+%2D+st%5B0+%2Dvampire++bat+tg%5B2+%2D+tg%5B1+%2D+tg%5B0+%2D+416C&fn=31&rn=36>.

 

∑           S.M. ≥Vampire Bats Donπt Learn from a Bad Lunch.≤ Science News 15 Mar. 2003. EbscoHost. 22 Feb 2004. <http://web12.epnet.com/citation.asp?tb=1&_ug=dbs+aph+sid+3799CDB4%2D78FA%2D419E%2DA173%2D2DE11BDE0798%40sessionmgr6+D2C5&_us=dstb+ES+fh+0+hd+0+hs+0+or+Date+ri+KAAACBUB00033025+sl+%2D1+sm+ES+ss+SO+B617&_uso=db%5B0+%2Daph+hd+0+op%5B2+%2DAnd+op%5B1+%2DAnd+op%5B0+%2D+st%5B2+%2D+st%5B1+%2D+st%5B0+%2Dvampire++bat+tg%5B2+%2D+tg%5B1+%2D+tg%5B0+%2D+416C&fn=1&rn=10>.

 

∑           ≥Vaulting Vampires.≤ Discover Mar. 1998. EbscoHost. 22 Feb. 2004. <http://web12.epnet.com/citation.asp?tb=1&_ug=dbs+aph+sid+3799CDB4%2D78FA%2D419E%2DA173%2D2DE11BDE0798%40sessionmgr6+D2C5&_us=dstb+ES+fh+0+hd+0+hs+0+or+Date+ri+KAAACBUB00033025+sl+%2D1+sm+ES+ss+SO+B617&_uso=db%5B0+%2Daph+hd+0+op%5B2+%2DAnd+op%5B1+%2DAnd+op%5B0+%2D+st%5B2+%2D+st%5B1+%2D+st%5B0+%2Dvampire++bat+tg%5B2+%2D+tg%5B1+%2D+tg%5B0+%2D+416C&fn=11&rn=11>.

 

∑           ≥Zapping Vampires.≤ Science News 14 July 1979. EbscoHost. 22 Feb. 2004. <http://web12.epnet.com/citation.asp?tb=1&_ug=dbs+aph+sid+3799CDB4%2D78FA%2D419E%2DA173%2D2DE11BDE0798%40sessionmgr6+D2C5&_us=dstb+ES+fh+0+hd+0+hs+0+or+Date+ri+KAAACBUB00033025+sl+%2D1+sm+ES+ss+SO+B617&_uso=db%5B0+%2Daph+hd+0+op%5B2+%2DAnd+op%5B1+%2DAnd+op%5B0+%2D+st%5B2+%2D+st%5B1+%2D+st%5B0+%2Dvampire++bat+tg%5B2+%2D+tg%5B1+%2D+tg%5B0+%2D+416C&fn=51&rn=55>.

 

 

 

            Brian Beechener

HONR278C Biology and Mythology of Bats

Professor Wilkinson

February 23, 2004