scholarly journals Social foraging in vampire bats is predicted by long-term cooperative relationships

PLoS Biology ◽  
2021 ◽  
Vol 19 (9) ◽  
pp. e3001366
Author(s):  
Simon P. Ripperger ◽  
Gerald G. Carter
Keyword(s):  
Social Evolution ◽  
Group Living ◽  
Food Sharing ◽  
Social Foraging ◽  
Social Grooming ◽  
Cooperative Relationships ◽  
Vampire Bats ◽  
In Captivity ◽  
Access To Food

Stable social bonds in group-living animals can provide greater access to food. A striking example is that female vampire bats often regurgitate blood to socially bonded kin and nonkin that failed in their nightly hunt. Food-sharing relationships form via preferred associations and social grooming within roosts. However, it remains unclear whether these cooperative relationships extend beyond the roost. To evaluate if long-term cooperative relationships in vampire bats play a role in foraging, we tested if foraging encounters measured by proximity sensors could be explained by wild roosting proximity, kinship, or rates of co-feeding, social grooming, and food sharing during 21 months in captivity. We assessed evidence for 6 hypothetical scenarios of social foraging, ranging from individual to collective hunting. We found that closely bonded female vampire bats departed their roost separately, but often reunited far outside the roost. Repeating foraging encounters were predicted by within-roost association and histories of cooperation in captivity, even when accounting for kinship. Foraging bats demonstrated both affiliative and competitive interactions with different social calls linked to each interaction type. We suggest that social foraging could have implications for social evolution if “local” within-roost cooperation and “global” outside-roost competition enhances fitness interdependence between frequent roostmates.

scholarly journals Social foraging in vampire bats is predicted by long-term cooperative relationships

2021 ◽  
Author(s):  
Simon P. Ripperger ◽  
Gerald G. Carter
Keyword(s):  
Social Evolution ◽  
Group Living ◽  
Food Sharing ◽  
Social Foraging ◽  
Social Grooming ◽  
Cooperative Relationships ◽  
Vampire Bats ◽  
In Captivity ◽  
Access To Food

AbstractStable social bonds in group-living animals can provide greater access to food. A striking example is that female vampire bats often regurgitate blood to socially bonded kin and nonkin that failed in their nightly hunt. Food-sharing relationships form via preferred associations and social grooming within roosts. However, it remains unclear whether these cooperative relationships extend beyond the roost. To evaluate if long-term cooperative relationships in vampire bats play a role in foraging, we tested if foraging encounters measured by proximity sensors could be explained by wild roosting proximity, kinship, or rates of co-feeding, social grooming, and food sharing during 22 months in captivity. We assessed evidence for six hypothetical scenarios of social foraging, ranging from individual to collective hunting. We found that female vampire bats departed their roost individually, but often re-united far outside the roost. Nonrandomly repeating foraging encounters were predicted by within-roost association and histories of cooperation in captivity, even when controlling for kinship. Foraging bats demonstrated both affiliative and competitive interactions and a previously undescribed call type. We suggest that social foraging could have implications for social evolution if ‘local’ cooperation within the roost and ‘global’ competition outside the roost enhances fitness interdependence between frequent roostmates.

scholarly journals Social dominance and cooperation in female vampire bats

2021 ◽  
Vol 8 (7) ◽  
pp. 210266
Author(s):  
Rachel J. Crisp ◽  
Lauren J. N. Brent ◽  
Gerald G. Carter
Keyword(s):  
Dominance Hierarchy ◽  
Social Rank ◽  
Group Living ◽  
Experimental System ◽  
Food Sharing ◽  
Competitive Interactions ◽  
Female Dominance ◽  
Cooperative Relationships ◽  
Vampire Bats ◽  
In The Wild

When group-living animals develop individualized social relationships, they often regulate cooperation and conflict through a dominance hierarchy. Female common vampire bats have been an experimental system for studying cooperative relationships, yet surprisingly little is known about female conflict. Here, we recorded the outcomes of 1023 competitive interactions over food provided ad libitum in a captive colony of 33 vampire bats (24 adult females and their young). We found a weakly linear dominance hierarchy using three common metrics (Landau's h ’ measure of linearity, triangle transitivity and directional consistency). However, patterns of female dominance were less structured than in many other group-living mammals. Female social rank was not clearly predicted by body size, age, nor reproductive status, and competitive interactions were not correlated with kinship, grooming nor food sharing. We therefore found no evidence that females groomed or shared food up a hierarchy or that differences in rank explained asymmetries in grooming or food sharing. A possible explanation for such apparently egalitarian relationships among female vampire bats is the scale of competition. Female vampire bats that are frequent roostmates might not often directly compete for food in the wild.

scholarly journals Development of new food-sharing relationships among nonkin vampire bats

2019 ◽  
Author(s):  
Gerald G. Carter ◽  
Damien R. Farine ◽  
Rachel J. Crisp ◽  
Julia K. Vrtilek ◽  
Simon P. Ripperger ◽  
...  
Keyword(s):  
Social Bonds ◽  
Low Cost ◽  
Food Sharing ◽  
Cooperative Relationships ◽  
Vampire Bats ◽  
Term Pair ◽  
Show Evidence ◽  
Survival And Reproduction ◽  
High Investment

AbstractIn an individualized animal society, social bonds can foster cooperation and enhance survival and reproduction. Cooperative bonds often exist among kin, but nonkin can also develop high-investment cooperative bonds that share similarities with human friendship. How do such bonds form? One theory suggests that strangers should ‘test the waters’ of a new relationship by making small initial cooperative investments and gradually escalating them with good partners. This ‘raising-the-stakes’ strategy is demonstrated by human strangers in short-term economic games, but it remains unclear whether it applies to helping in a natural long-term social bond. Here we show evidence that unfamiliar vampire bats (Desmodus rotundus) selectively escalate low-cost investments in allogrooming before developing higher-cost food-sharing relationships. We introduced females from geographically distant sites in pairs or groups and observed that bats established new reciprocal grooming relationships, and that increasing grooming rates predicted the occurrence of first food donations, at which point grooming rates no longer increased. New food-sharing relationships emerged reciprocally in 14% of female pairs, typically over 10-15 months, and developed faster when strangers lacked alternative familiar partners. A gradual grooming-to-sharing transition among past strangers suggests that ‘raising the stakes’ might be more evident when tracking multiple cooperative behaviours as new relationships form, rather than measuring a single behavior in an established relationship. ‘Raising the stakes’ could play a similar underappreciated role across a broader spectrum of social decisions with long-term consequences, such as joining a new social group or forming a long-term pair-bond.Significance statementVampire bats form long-term cooperative social bonds that involve reciprocal food sharing. How do two unrelated bats go from being strangers to having a high-investment food-sharing relationship? We introduced unfamiliar bats and found evidence that low-cost grooming paves the way for higher-cost food donations. Food sharing emerged in a reciprocal fashion and it emerged faster when two strangers did not have access to their original groupmates. The bats that formed new food-sharing relationships had a history of escalating reciprocal grooming up until the food sharing began. Our finding that unfamiliar nonkin vampire bats appear to gradually and selectively transition from low-cost to high-cost cooperative behaviors is the first evidence that nonhuman individuals ‘raise the stakes’ when forming new cooperative relationships.

scholarly journals Effects of food type and abundance on begging and sharing in Asian small-clawed otters (Aonyx cinereus)

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10369
Author(s):  
Madison Bowden-Parry ◽  
Erik Postma ◽  
Neeltje J. Boogert
Keyword(s):  
Group Living ◽  
Theoretical Models ◽  
Food Sharing ◽  
Food Type ◽  
Honest Signal ◽  
Age Classes ◽  
Research Attention ◽  
In Captivity ◽  
Living Species ◽  
Age Category

Begging for food, a conspicuous solicitation display, is common in a variety of taxa, and it has received extensive research attention in a parent-offspring context. Both theoretical models and empirical evidence suggest that offspring begging can be an honest signal of hunger or a mediator of competition between siblings. At a behavioural mechanistic level, begging for food can be a form of harassment aimed at persuading those in possession of food to share. Food sharing, defined as the transfer of a defendable food item from one individual to another, can vary considerably between species, age-classes and food type and abundance. We investigated the determinants of begging and food-sharing behaviours in Asian small-clawed otters (Aonyx cinereus), a group-living species that commonly exhibits begging in captivity. We presented two captive otter populations with three food types that varied in exploitation complexity, in three different abundances. We predicted that begging rates would be highest when food was in lowest abundance and hardest to exploit, and that increased begging would lead to increased food sharing. We found that, over time, increased begging rates were indeed correlated with increased food transfers, but neither food type complexity nor abundance affected begging or sharing rates. However, age category was significantly associated with begging and food sharing rates: juvenile otters begged more and shared less than adult otters. The results from this first experimental study on begging and food sharing within the Mustelid family begin to reveal some of the drivers of these behaviours.

scholarly journals Non-kin cooperation in bats

2016 ◽  
Vol 371 (1687) ◽  
pp. 20150095 ◽  
Author(s):  
Gerald S. Wilkinson ◽  
Gerald G. Carter ◽  
Kirsten M. Bohn ◽  
Danielle M. Adams
Keyword(s):  
Social Bonds ◽  
Food Sharing ◽  
Alloparental Care ◽  
Field Observations ◽  
Desmodus Rotundus ◽  
Vampire Bats ◽  
Phyllostomus Hastatus ◽  
Related Individuals

Many bats are extremely social. In some cases, individuals remain together for years or even decades and engage in mutually beneficial behaviours among non-related individuals. Here, we summarize ways in which unrelated bats cooperate while roosting, foraging, feeding or caring for offspring. For each situation, we ask if cooperation involves an investment, and if so, what mechanisms might ensure a return. While some cooperative outcomes are likely a by-product of selfish behaviour as they are in many other vertebrates, we explain how cooperative investments can occur in several situations and are particularly evident in food sharing among common vampire bats ( Desmodus rotundus ) and alloparental care by greater spear-nosed bats ( Phyllostomus hastatus ). Fieldwork and experiments on vampire bats indicate that sharing blood with non-kin expands the number of possible donors beyond kin and promotes reciprocal help by strengthening long-term social bonds. Similarly, more than 25 years of recapture data and field observations of greater spear-nosed bats reveal multiple cooperative investments occurring within stable groups of non-kin. These studies illustrate how bats can serve as models for understanding how cooperation is regulated in social vertebrates.

scholarly journals Evidence for unfamiliar kin recognition in vampire bats

2019 ◽  
Author(s):  
Simon P. Ripperger ◽  
Rachel A. Page ◽  
Frieder Mayer ◽  
Gerald G. Carter
Keyword(s):  
Kin Recognition ◽  
Social Experience ◽  
Kin Discrimination ◽  
Desmodus Rotundus ◽  
Cooperative Relationships ◽  
Kin Competition ◽  
Vampire Bats ◽  
In Captivity ◽  
Social Encounters ◽  
Free Ranging

AbstractKin discrimination allows organisms to preferentially cooperate with kin, reduce kin competition, and avoid inbreeding. In vertebrates, kin discrimination often occurs through prior association. There is less evidence for recognition of unfamiliar kin. Here, we present the first evidence of unfamiliar kin recognition in bats. We captured female vampire bats (Desmodus rotundus) from a single roost, allowed them to breed in captivity for 22 months, then released 17 wild-caught females and six captive-born daughters back into the same wild roost. We then used custom-built proximity sensors to track the free-ranging social encounters among the previously captive bats and 27 tagged control bats from the same roost. Using microsatellite-based relatedness estimates, we found that previously captive bats preferentially associated with related control bats, and that captive-born bats preferentially associated with unfamiliar kin among control bats. Closer analyses showed that these unfamiliar-kin-biased associations were not caused by mothers or other familiar close kin, because the kinship bias was evident even when those bats were not nearby. This striking evidence for unfamiliar kin recognition in vampire bats warrants further investigation and provides new hypotheses for how cooperative relationships might be driven synergistically by both social experience and phenotypic similarity.

scholarly journals Food sharing is linked to urinary oxytocin levels and bonding in related and unrelated wild chimpanzees

2014 ◽  
Vol 281 (1778) ◽  
pp. 20133096 ◽  
Author(s):  
Roman M. Wittig ◽  
Catherine Crockford ◽  
Tobias Deschner ◽  
Kevin E. Langergraber ◽  
Toni E. Ziegler ◽  
...  
Keyword(s):  
Social Bonding ◽  
Food Sharing ◽  
Social Bond ◽  
Cooperative Behaviour ◽  
Cooperative Relationships

Humans excel in cooperative exchanges between unrelated individuals. Although this trait is fundamental to the success of our species, its evolution and mechanisms are poorly understood. Other social mammals also build long-term cooperative relationships between non-kin, and recent evidence shows that oxytocin, a hormone involved in parent–offspring bonding, is likely to facilitate non-kin as well as kin bonds. In a population of wild chimpanzees, we measured urinary oxytocin levels following a rare cooperative event—food sharing. Subjects showed higher urinary oxytocin levels after single food-sharing events compared with other types of social feeding, irrespective of previous social bond levels. Also, urinary oxytocin levels following food sharing were higher than following grooming, another cooperative behaviour. Therefore, food sharing in chimpanzees may play a key role in social bonding under the influence of oxytocin. We propose that food-sharing events co-opt neurobiological mechanisms evolved to support mother–infant bonding during lactation bouts, and may act as facilitators of bonding and cooperation between unrelated individuals via the oxytocinergic system across social mammals.

Periodic monitoring of vampire bats and rabies: a new framework for animal restoration projects in the Neotropics

2020 ◽  
Author(s):  
Fernando Gonçalves ◽  
Daniel G. Streicker ◽  
Mauro Galetti
Keyword(s):  
Disease Transmission ◽  
Lessons Learned ◽  
Multidisciplinary Teams ◽  
Risk Area ◽  
Food Web Structure ◽  
Land Bridge ◽  
High Risk Area ◽  
Restoration Project ◽  
Vampire Bats

Nowadays, restoration project might lead to increased public engagement and enthusiasm for biodiversity and is receiving increased media attention in major newspapers, TED talks and the scientific literature. However, empirical research on restoration project is rare, fragmented, and geographically biased and long-term studies that monitor indirect and unexpected effects are needed to support future management decisions especially in the Neotropical area. Changes in animal population dynamics and community composition following species (re)introduction may have unanticipated consequences for a variety of downstream ecosystem processes, including food web structure, predator-prey systems and infectious disease transmission. Recently, an unprecedented study in Brazil showed changes in vampire bat feeding following a rewilding project and further transformed the land-bridge island into a high-risk area for rabies transmission. Due the lessons learned from ongoing project, we present a novel approach on how to anticipate, monitor, and mitigate the vampire bats and rabies in rewilding projects. We pinpoint a series of precautions and the need for long-term monitoring of vampire bats and rabies responses to rewilding projects and highlighted the importance of multidisciplinary teams of scientist and managers focusing on prevention educational program of rabies risk transmitted by bats. In addition, monitoring the relative abundance of vampire bats, considering reproductive control by sterilization and oral vaccines that autonomously transfer among bats would reduce the probability, size and duration of rabies outbreaks. The rewilding assessment framework presented here responds to calls to better integrate the science and practice of rewilding and also could be used for long-term studying of bat-transmitted pathogen in the Neotropical area as the region is considered a geographic hotspots of “missing bat zoonoses”.

scholarly journals Family feud: permanent group splitting in a highly philopatric mammal, the killer whale (Orcinus orca)

2021 ◽  
Vol 75 (3) ◽  
Author(s):  
Eva H. Stredulinsky ◽  
Chris T. Darimont ◽  
Lance Barrett-Lennard ◽  
Graeme M. Ellis ◽  
John K. B. Ford
Keyword(s):  
Killer Whale ◽  
Group Structure ◽  
Group Living ◽  
Orcinus Orca ◽  
Learning Approaches ◽  
Killer Whales ◽  
Internal Factors ◽  
Individual Fitness ◽  
Leadership Experience

Abstract For animals that tend to remain with their natal group rather than individually disperse, group sizes may become too large to benefit individual fitness. In such cases, group splitting (or fission) allows philopatric animals to form more optimal group sizes without sacrificing all familiar social relationships. Although permanent group splitting is observed in many mammals, it occurs relatively infrequently. Here, we use combined generalized modeling and machine learning approaches to provide a comprehensive examination of group splitting in a population of killer whales (Orcinus orca) that occurred over three decades. Fission occurred both along and across maternal lines, where animals dispersed in parallel with their closest maternal kin. Group splitting was more common: (1) in larger natal groups, (2) when the common maternal ancestor was no longer alive, and (3) among groups with greater substructuring. The death of a matriarch did not appear to immediately trigger splitting. Our data suggest intragroup competition for food, leadership experience and kinship are important factors that influence group splitting in this population. Our approach provides a foundation for future studies to examine the dynamics and consequences of matrilineal fission in killer whales and other taxa. Significance statement Group living among mammals often involves long-term social affiliation, strengthened by kinship and cooperative behaviours. As such, changes in group membership may have significant consequences for individuals’ fitness and a population’s genetic structure. Permanent group splitting is a complex and relatively rare phenomenon that has yet to be examined in detail in killer whales. In the context of a growing population, in which offspring of both sexes remain with their mothers for life, we provide the first in-depth examination of group splitting in killer whales, where splitting occurs both along and across maternal lines. We also undertake the first comprehensive assessment of how killer whale intragroup cohesion is influenced by both external and internal factors, including group structure, population and group demography, and resource abundance.

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