Social interactions help vampire bats ease their unusual blood diet

You can probably imagine a vampire: a pale, fanged, undead bloodsucker repelled only by sunlight, religious paraphernalia and garlic. They are brute creatures and are often beloved characters in movies and books. Luckily, they’re just imaginary…or are they?

There are real vampires. bat world. Of the more than 1,400 currently described bat species, three are known to feed exclusively on blood.

an ordinary vampire bat, Desmodus roundis the most numerous. These bats live at home in the tropical forests of Central and South America. eat various animalsincluding tapirs, mountain lions, penguins and, most commonly these days, livestock.

Eating a blood diet is unusual for mammals and has led to many unique adaptations that facilitate their unusual lifestyle. Unlike other bats, vampires are mobile on earthswitching between two different gaits to surround sleeping prey. Heat-sensing receptors on the nose help them find warm blood under the victim’s skin. Finally, the combination of a small incision made potentially self-sharpening fangsAnd anticoagulant in saliva allows these bats to feed on unsuspecting prey.

To me, as a behavioral ecologistwho is interested in how pathogens influence social behavior and vice versa, the most interesting adaptation to a blood-feeding lifestyle can be observed in the social life of vampire bats.

Vampire bats build mutual relationships

Blood is not very nutritious, and vampire bats that do not feed will starve to death relatively quickly. If the bat returns to his place hungryothers may regurgitate blood meal to survive their night.

This food sharing occurs between related bats (for example, mothers and their offspring), as well as between unrelated individuals. This observation has long puzzled evolutionary biologists. Why help someone who is not closely related to you?

It turns out that bats are vampires keep track of who feeds them and reciprocate – or not, if another bat has not helped in the past. In doing so, they form complex social relationships, supported by low-cost social investments such as grooming and grooming another animal (called allogrooming) and more expensive social investments such as sharing food.

These relationships are similar to those seen in primates, and some people compare them to human friendships. Indeed, there are some parallels.

For example, people will raise stakes when forming new relationships with others. You start with a social investment that doesn’t cost much (think about sharing part of your lunch) and wait for the other person’s reaction. If they don’t reciprocate, the relationship may be doomed. But if the other person reciprocates, perhaps by sharing a piece of their dessert, your next investment could be larger. You gradually increase the stakes in a back-and-forth game until the friendship eventually requires a larger social investment, like when you go out of your way to give them a ride to work when their car breaks down.

Vampire bats do the same thing. When strangers meet, they begin with small fur-brushing interactions to test the waters. If both partners continue to reciprocate and raise the stakes, relationships will get worse over time to sharing food, which is a more serious commitment.

Relationships in sickness and health

My lab studies how infections affect social behavior and relationships. Given the wide range of social behavior and the complexity of social relationships, vampire bats provide an ideal learning system for me and my colleagues.

How does disease affect the behavior of vampire bats? How do other bats behave towards the sick person? How does the disease affect the formation and maintenance of their social relationships?

In our laboratory, we model infections in bats by using pathogen-derived molecules to stimulate an immune response. We have repeatedly found a form of passive social distancing in which sick people reduce their interactions with others, whether allogrooming, social vocation or just spend time around others.

It is important to note that these behavioral changes are not necessarily aimed at minimizing the spread of the disease to others. Rather, they are part of a complex immune response that biologists call sick behavior. It’s comparable to someone caught the flu while staying at home simply because they don’t want to go outside. Even though this kind of passive social distancing may not have been designed to prevent transmission of the virus to others, simply being too sick to interact with others will still reduce the spread of germs.

Interestingly, painful behavior can be suppressed. People do this all the time. The so-called presenteeism appears at work despite illness due to various stresses. Likewise, many people suppress symptoms of infection in order to fulfill some social obligations. If you have small children, you know that when everyone in your family gets sick, you can’t just sit back and not take care of the little ones, even if you feel very sick yourself.

Animals are no different. They can suppress painful behavior when competing needs arise, such as caring for young or defending a territory. Despite their tendency to decrease social interaction with others during illness, vampire bats sick mothers will continue to care for their offspring and vice versa, probably because the mother-daughter relationship is so important. Mothers and daughters are often each other’s primary social bonds in vampire bat groups.

Human-bat conflict linked to livestock

Despite their many interesting adaptations and complex social lives, vampire bats are not universally admired. In fact, in many areas of South and Central America they are considered pests because they can transmit the deadly rabies virus to livestock, which can cause very significant economic losses.

Before humans introduced livestock into their habitat, vampire bats likely had a more difficult time finding food in the form of native prey species such as tapirs. Now livestock has become their main source of food. After all, why not eat something that is in the same place every night and in sufficient quantities? Increase in livestock numbers will occur with an increase in the vampire bat populationlikely perpetuating the problem of rabies transmission.

Farmers’ quarrels with vampires make sense, especially in small cattle herds where the loss of even one cow can significantly undermine a farmer’s livelihood. The culling campaigns used topical poisons. called vampiricide and is a mixture of petroleum jelly and rat poison. The bats are captured, the paste is applied to their fur, and taken back to the roost, where others absorb the poison during social interaction. It’s interesting how big it is. culling may not be very effective in reducing rabies incidence overflow

Now the focus has begun to shift towards large-scale vaccination of cattle or vaccination of vampire bats themselves. Researchers even considering transmissible vaccines: They could genetically modify herpes viruseswhich are quite common in vampire bats, carry rabies genes and allow large populations of vampire bats to be vaccinated.

Whatever method is used to mitigate conflicts between vampire bats and humans, greater empathy for these misunderstood animals can only help. After all, if you stick your head into a hollow tree full of vampire bats (assuming you can stand the smell of digested blood), remember: you’re looking at a complex network of individual friendships between animals that care deeply about each other.

This article is republished from The Conversation under a Creative Commons license. Read the original article Here.