Vampire+Bat


 * Common Vampire Bat (Desmodus Rotundus) ** //The Modern Day Vampire Bat by Jacqui Chiu// **﻿Extinct Animal:** Icaronycteris Index  **Future Animal:** Mixed Bat

**Habitat of the Common Vampire Bat**

The common vampire bat is only found naturally in the Southern Hemisphere and only on the continent of South America. Their habitat is spread over a large area from countries like Northern Mexico, Chile, Argentina, Uruguay to islands such as Margarita, Trinidad and Venezuela. Although they are scattered all over South America, they will always be found in clusters due to the distribution of their food source which tends to be found in large groups. These countries in South America is warm all-year round, with a tropical or subtropical climate. This is the ideal living condition for vampire bats. Additionally, the geography of the area is a flat terrain and is an attractive habitat for their prey to live in. Vampire Bats do not live in mountainous regions, not only because it is too far from the food source, but also because the temperature there would be too low and they would have difficulties surviving.

The vampire bat lives in a luscious environment with diverse animal species. Whether their environment is the rainforest, dry deserts or farmlands they will only be found in clusters near their prey. Even though they can fly properly, and not just glide through the air like sugar gliders, they will not be more than 10km away from their prey as they will waste too much energy. The most common animals near vampire bats are farm animals like cows, horses, pigs, sheep and donkeys. This explains why the vampire bat's nautral prey is only found in clusters as farmers prefer living in the same area that contains rich land. Although these animals are not their natural prey, the introduction of these species by humans had made hunting for food much easier as farm animals do not move as fast as other wild animals do. Some of the animals found in the vampire bat’s environment are its predators which includes eagles, hawks and sometimes even vultures! Other land mammals are not really much of a threat to the bat as they are mostly asleep when vampire bats roam around at night to hunt.

The vampire bat is most commonly found in humid areas, even though they can survive in both wet and dry areas they prefer to live in moist areas. The climate of their habitat is either tropical or subtropical, making South America the perfect place to live. The temperature is quite constant throughout the year (making it easy to adapt to), but generally the nights are much cooler than the daytime. However, because vampire bats cannot hibernate, during the cold months of winter, they will require more energy to survive. This is why they cannot be found in regions that are cooler than the tropics of South America.

The vampire bats are found mainly in damp areas like caves, but will reside in any other dark and high areas (they have been recorded to live in places that are 2300 meters high!) such as mines, the hollows of trees and even abandoned buildings. This was important as the dark camouflages them, providing protection. The vampire bat lives in colonies of 100 to 1000 bats as there is a safety in numbers. Both sexes will roost together, but females and their offspring will form tighter groups known as harems and a dominant male will join one of these groups. The living area of vampire bats expels a strong smell of ammonia due to their diet of blood. Vampire bats roosts with several other bat species but because of its dominance and aggressiveness, they occupy the highest spot in the cave and only when they migrate to areas nearer their prey would other bats take their space.

**Labelled photograph of the Common Vampire Bat**

**Adaptations of the Common Vampire Bat** **1. Blood Sharing** Vampire bats only consume blood. Their average daily blood consumption is around 20 to 25ml. If it cannot find food for two days it will starve to death. In fact, it is quite difficult to find food; adult bats are unsuccessful 7% of the time and young bats 33%. To help another bat to survive, vampire bats are able to regurgitate blood for donation; the donor only loses 6 hours of survival but the recipient gains 18 hours. Although this altruistic behavior goes against nature, the role of recipient and donor frequently reverses depending on which bat cannot find food that night. In their lifetime, each bat would have shared and received equal amounts of food which means that they would have increased their overall hours of survival and their opportunity to live. If they had not contributed to this blood-sharing behavior, they may have died before they are mature enough to breed.

The environmental pressure that may have lead to this adaptation may be due to a sudden food scarcity. During the Ice Age, mammals such as horses, camels and giant sloths in the continent died off as they were unable to adapt to the weather. This would have reduced the amount of food for vampire bats, and only bats that were willing to share blood would have been able to survive.

2. Living in Colonies Vampire bats live together in large colonies made up of 100 to 1000 bats. Within this large colony, bats form smaller groups between unrelated females and their offspring, males are territorial and will choose to join these groups. By living in large colonies, the vampire bat is able to depend on each other for survival. A larger colony increases their chances of survival as it becomes easier to find a donor to stop itself from starvation, thus they will be able to live longer. The environmental pressure that caused this change would be the unpredictability and difficulty of finding food at some point in time.

Another environmental pressure is due to the cold South America nights. Blood is the vampire bat’s main food source but since there is no energy stored in blood, they are unable to store fat to keep warm. To ensure their own and their partner’s survival, smaller groups within colonies will gather together to preserve body heat. This will conserve their energy as well. Due to their small size, they are easily attacked by their large and clever predators such as eagles and hawks. There is a safety in numbers as predators are unlikely to attack a colony of vampire bats as they are outnumbered. This reduces the possibility of a vampire bat becoming another’s prey. The bat’s predators are continuously adapting to the environment and to survive, the vampire bat has to keep pace with their adaptation. The predators have become more and more intelligent, knowing to wait for lone bats that leave the cave to hunt, to protect themselves bats now go hunting within the large groups formed in the colony.

Vampire bat’s food source (farm animals) is found in clusters on farms. This creates an abundance of food in one area and not in another which may have caused all the bats to want to live close to their food source, thus saving energy of having to fly around to seek food. The more energy they have, the longer they can live for. With this mindset, vampire bats would have found themselves living together in the same area.

The vampire bat has developed teeth that are different to that of other bats. Due to their pure liquid diet, vampire bats (with a tooth count of 20) have fewer teeth since they do not need to chew. Having fewer teeth is also an advantage as less nutrients are wasted in maintain the teeth, and this can also lessen the overall body mass of a vampire bat. This allows them to fly faster and be able to escape from its predators.
 * [[image:vampire_bat_teeth].jpg width="283" height="266" align="left" caption="Image of a vampire bat showing its teeth"]]3. Teeth**

Their upper incisors have developed and become very sharp and shaped like canines. Since these incisors lack enamel, it can be kept very sharp allowing painless bites. This is crucial as it stops its prey from awakening, letting the bats drink more blood. If its prey awakens, the tiny vampire bat is vulnerable as they can be easily killed by its large victim. Additionally, their sharp teeth allow for precise incisions into the victim’s skin and avoids cutting into arteries or veins; they would not want to kill their prey as vampire bats feed on the same host each night.

The environmental pressure that would have lead to this change in their teeth structure would have been the emergence of new species in the bat’s environment. Scientist believes that the vampire bat evolved from insect-eating bats, eating insects that were scattered around the wounds of large animals. At some point, the temperature on Earth was warm and moist enough for plants to thrive leading to an increase of insect-eating mammals. This introduction of new animal species made it difficult for vampire bats to survive. Unless they found an alternate food source, vampire bats would become extinct. Thus they began also feeding on the blood of the animals (which the insects formed around) to avoid starvation. Eventually the competition was too strong which lead to a complete shift in their diet. Some time later, the influx of cattle in South America made the bats dependent on cattle blood and to penetrate through their skin they would have had to develop sharp teeth.

Although the vampire bat's legs look weak, it is actually very strong and made of muscle. By having such strong leg muscles, vampire bats are able to move along the ground with ease unlike other bats who have lost the ability to manoever on land. This is important as vampire bats need to land a few meters away from their prey before slowly crawling towards them for feeding. If they land directly on their prey, there is a greater chance of them awakening. Due to their large size and unpredictable behavior, their prey can easily kill the vampire bat. Additionally, having strong leg muscles lets them push off vertically from the ground and dart to the safety of the skies, far away from the threats of land mammals. This efficient escape method accelerates take-off and propels them into the air after a heavy meal too (they would have drunk so much blood their wings would be unable to lift them easily off the ground).
 * [[image:Vampire_bat_crawl.jpg width="342" height="235" align="right" caption="Vampire bat crawling along the ground"]]4. Developed leg muscles**

A possible environmental pressure that caused this adaptation would be the change in diet. All bats once had the ability to maneuver on land to forage for food. When they developed wings, it became easier for them to rely on their ability to fly to escape dangerous situations. Soon their leg muscles weakened, but vampire bats developed muscles again due to an increased competition for food in the wild. To increase the chances of survival, they evolved and changed their diet from insects to small land mammals. This created the need to chase their prey on the ground as they often escaped during feeding. It was more efficient to chase after them as soon as they escaped, rather than wasting time to launch into the air and then fly after them. It was only with the emergence of larger land mammals that vampire bats became even more reliant on their leg muscles.

Like whales and dolphins, the vampire bat uses echolocation to travel around at night. By vibrating air in their vocal cords, vampire bats can emit high frequency waves through its nose and mouth while it flies. These sound waves will bounce off any object and return to them in the form of echoes, carrying information on the food source, its size and type and whether it will be safe to approach them or not. This helps them survive and reproduce because if they were not aware of how far their prey was, they may approach too noisily and scare them off which mean that the vampire bat will starve to death. Contrary to popular belief, the vampire bat is not blind. They are able to see but by using echolocation they can navigate easier at night. For example, they can avoid crashing into trees and such unnesscary deaths. Echolocation also protects the bats from predators as their senses are heightened, and despite the lack of light during nighttime, they are able to keep safe.
 * 5. Echolocation**

The environmental pressure leading to this adaptation would be the night environment. Vampire bats are nocturnal creatures therefore no matter how keen their eyes are they cannot rely on sight to navigate through a thick forest in total darkness, they would be too vulnerable. Instead echolocation gives very precise data on the exact location of objects and when used in conjunction with sight becomes very efficient. Another possible pressure would have been because of their diet. As previously stated, vampire bats evolved from insect-eating bats. It would have been extremely difficult to locate tiny creatures at night, but bats that could echolocate would immediately find the precise location, distance and speed of an insect, enabling them to eat more and gain more energy. A stronger bat would be more able to pass on their genes to the next generation, who would also have the ability to echolocate.

**Bibliography:** //Websites//
 * 1) Buzzle. (2011). //Vampire Bat.// Retrieved June 13, 2011 from []
 * 2) Centre for Bat Conservation. (n.d.). //The Common Vampire Bat.// Retrieved June 13, 2011 from []
 * 3) Naish, D. (2007). //Giant extinct vampire bats: bane of Pleistocene megafauna.// Retrieved June 14, 2011 from []
 * 4) National Geographic. (2011). //Vampire Bat Facts and Pictures.// Retrieved June 13, 2011 from []
 * 5) Perry, J. (2002). //Reciprocal Altruism in Common Vampire Bats.// Retrieved June 15, 2011 from <span style="font-family: 'Arial','sans-serif'; font-size: 13px;">[|[[http://www.bio.davidson.edu/people/vecase/Behavior/Spring2002/perry/altruism.html]]]
 * 6) <span style="font-family: 'Arial','sans-serif'; font-size: 13px;">Unknown. (n.d.). //Vampire Bat (Desmodus Rotundus).// Retrieved June 15, 2011 from []