Wild horses show signs of societal structure
Reports in Scientific reports, an international team of researchers from Kyoto University and the University of Strasbourg used drones to study the “multi-level societal structure” of wild horses in Serra D’Arga, Portugal.
In a multilevel society, individuals are structured into stable groups which establish relationships with other groups to form a higher level of organization. For example, people live in a multilevel society where families form a local community which in turn combines with others to form a higher social organization such as suburbs and cities.
The phenomenon has been studied in animals such as primates and whales. Studying multilevel societies in animals may give us insight into how these relationships work, but their mechanisms are still under-studied due to a lack of quantitative data. “That’s why we chose to study the social apparatus of wild horses,” says research team leader Shinya Yamamoto.
The team set up an area to observe a well-documented group of horses in Serra D’Arga, Portugal. Their drone took aerial photos at 30-minute intervals, allowing them to accurately record the locations of each horse and the exact distances between individuals.
The use of drones allowed them to identify 121 individuals within 23 specifically defined groups called units, and 5 solitary males. Two categories were used to describe the groups: “harems” —mixed genders with one or two adult males — and all male “singles groups”.
Analysis of the team’s data found three lines of evidence: 1) small social organizations or “units” exist and they will merge to form higher level “herds”; 2) groups of singles stay on the periphery of a herd; and 3) large harems were more likely to occupy the center of the herd, explains first author Tamao Maeda.
We often see in social animals that dominant individuals occupy the center of a group. Therefore, the data suggests that large harems indicate their higher status within group relationships.
“In addition, removing singles from the center can reduce the risk of them harassing individuals and potentially taking over harems,” adds Maeda.
The team is excited about the prospects of their new findings, encouraging them to delve deeper into the functions and mechanisms of societies at multiple levels in horses, as well as to use their methods to study other social species.
Behavioral synchronization in complex wild horse societies
Tamao Maeda et al, Aerial drone observations have identified a tiered society in wild horses, Scientific reports (2021). DOI: 10.1038 / s41598-020-79790-1
Quote: Wild horses show signs of societal structure (2021, December 27) retrieved December 27, 2021 from https://phys.org/news/2021-12-feral-horses-evidence-societal.html
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