The national lockdown to contain covid in 2020 was a situation never seen before for the vast majority of people. However, the scientific community soon realized that human beings are not so original. We are not the only species that maintains social distance to prevent the spread of a disease: vampire bats do it too.
This is just one resemblance among many that we have with these flying mammals. They too they are one of the few species where favors between individuals are returned later. Vampire favors consist of grooming each other and (in the case of females) regurgitating the blood they draw from other animals to feed those in need.
But the most amazing thing we share with vampires is our way of forming social bonds. A few months ago, a study found that female vampire bats that share a roost do not necessarily go hunting together, but they often meet again and cooperate during the hunt. They could recognize each other by voicesharing information about where the prey is or where there is an open wound from which they can feed.
trio of bats
Now, another study published in Biology Letters It goes further: it shows that with a close coexistence of only one week, bonds are forged that last for months. As if they were students, the “dorms” mark these bats for a long time weather.
This type of behavior is difficult to verify by pure observation, so the research team designed an ingenious social experiment to study how vampires relate.
The team chose three vampire bat roosts far from each other, capturing seven females from each. In a first phase of six weeks, the 21 vampires all lived together, until they were separated into seven groups. Each group had one bat from each of the initial roosts. A) Yes, the science team forced three almost unknown vampires to live together for a week in the second phase of the experiment. Then, for the third phase, all the vampires lived together again for another nine weeks.
How to measure the social interactions of vampires? The science team decided to observe when they groomed each other. For this, they installed thermal cameras that detected movement, and measured interactions of 5 seconds or more during all phases of the experiment.
They confronted the interactions between bats before and after forced coexistence, and also compared three groups of bats: those who had lived in the same trio during the central week of the experimentthose who shared a roost before the experiment and those from different roosts that had not lived together as a trio.
nine weeks of dating
As expected, trio coexistence favored interactions between bats at the beginning of the third phase of the experiment. But, To the surprise of the research team, this trend continued until the end. Bats in the same trio groomed each other more than those in the other two groups during all nine weeks.
It is true that already in the first phase, some of the bats that would end up living as a trio were already beginning to interact with each other. But the analysis was focused on studying the effect of coexistence in small groups, as well as its duration.
The most extraordinary thing about this experiment is that the vampires preferred to interact with their new “roommates” than with the roommates with whom they had lived for much more than a week. It’s more, the research team emphasizes that there is no doubt about this effectsince it was clearly observed in all the statistical analyzes that were applied to the data.
This is yet another characteristic that humans share with vampire bats.: close coexistence forges very strong ties even if it occurs for a short time. But there is a long way to go from here to unraveling the keys to how social bonds are created in nature.
It is not just about knowing ourselves better as people, and knowing what social behaviors we carry in our animal essence. It is also a question of the welfare of the animals themselves, since the way they socialize affects their health, survival and reproductive success.
There are still many questions to be answered, and to do so we will have to study the behavior of other animals. Do they relate to individuals who are most similar to them, or do opposites attract? Does coexistence guarantee close ties, or is initial cooperation needed for these ties to be created?
This experiment on vampire bats, as Gerald Carter points out, already shows that living together, even if forced, causes a social bond. Carter is a professor of evolution, ecology, and organismal biology at The Ohio State University. Perhaps this conclusion explains the fact that we are still friends with that roommate from the university. or even that friend with whom you shared a room at a summer camp.
As Carter recalls, “the process of how social bonds are formed is something fundamentally mysterious that interests many people, but everyone has their own interpretation of how it happens. Works like this, hopefully, will help us come to an agreement.
DO NOT SCREW IT:
- Vampires have existed in mythology long before the namesake species of bat were known in Europe. Bats that feed on blood arrived in Europe from America for the first time in the 16th century, at the hands of the Spanish colonizers. But they had to wait another century to acquire the vampire man.
- Of the more than 1,400 bat species that exist today, only three feed on blood: the common vampire bat (Desmodus rotundus), the hairy-legged vampire (Diphylla ecaudata) and the white-winged vampire (Diaemus youngi). The common vampire usually drinks blood from mammals such as horses, cows or pigs, while the other two prefer birds.
- Razik, Imran; Brown, Bridget, et al. Biology Letters, Royal Society Publishing, http://dx.doi.org/10.1098/rsbl.2022.0056
- Ripperger, Simon P., and Gerald G. Carter. “Social Foraging In Vampire Bats Is Predicted By Long-Term Cooperative Relationships.” PLOS Biology, vol 19, no. 9, 2021, p. e3001366. Public Library Of Science (Plos), https://doi.org/10.1371/journal.pbio.3001366.
- Ripperger, Simon P et al. “Tracking Sickness Effects On Social Encounters Via Continuous Proximity Sensing In Wild Vampire Bats”. Behavioral Ecology, vol 31, no. 6, 2020, p. 1296-1302. Oxford University Press (OUP), https://doi.org/10.1093/beheco/araa111.