DOI: 10.5061/dryad.djh9w0w6f
title: The socioecology of elephants: Analysis of the processes creating multitiered social structures

description: In this paper, we investigate the formation and function of the
 multilevelled, fission–fusion social structure in a free-ranging African
 elephant, Loxodonta africana, population. We quantitatively identified the
 existence of four social tiers by using cluster analysis on individual
 association data. We assessed the effects of season and study period on
 social structuring and levels of cohesion within and among social units.
 We found that second-tier units, potentially the equivalent of the
 ‘family’, were stable across seasonal periods but the number of units
 increased as the study progressed and the population grew. It appears that
 these units were sufficiently small not to be influenced by ecologically
 related factors, such as resource competition, that might otherwise lead
 to them splitting. On the other hand, third- and fourth tier units were
 significantly affected by season in a way that suggests a trade-off
 between ecological costs (e.g. from resource competition) and different
 social and ecological benefits (e.g. from predator defence,
 territoriality, knowledge sharing and rearing of young). Age structure
 also appeared to influence this multitiered social organization. The size
 of second-tier social units was significantly affected by the age of
 matriarchs: units lead by matriarchs likely to be grandmothers (i.e.
 females 35 years and older) were significantly larger than those lead by
 younger matriarchs. We present a conceptual framework for understanding
 the emergence of multiple-tier social structure from interactions driven
 by socioecological processes. This study is the first to use rigorous
 quantitative methods to statistically show the existence of four
 hierarchical tiers of social organization in a nonhuman animal.
 Additionally, our results elucidate the role that ecological processes
 play in producing complex social structures.
description: The submitted data are Association Distance Matrices of adult,
 free ranging female African elephants inhabiting the Samburu ecosystem of
 northern Kenya. Association distance was calculated as 1 - Association
 Index (AI) values, where the simple ratio index is used to calculate AI
 Values using association data collected by registering all elephants
 encountered along four established reserve transects (date, time, GPS
 coordinates, group size, individuals present, and observation accuracy
 were recorded). Elephants were considered to be associating when
 behaviorally coordinated and spatially cohesive within 500m of an
 observer-estimated center. Only observation where the observer was
 completely certain of identifying all individuals in the group. For more
 details see:   WITTEMYER,
 G., Douglas-Hamilton, I., & Getz, W.M. 2005. The socio-ecology of 
  elephants: Analysis of the processes creating multileveled societies.
 *Animal Behaviour* 69:1357-1371 Goldenberg, S. Z.*,
 Douglas-Hamilton, I., WITTEMYER, G. 2016*. Vertical transmission of social
 roles drives resilience to poaching in elephant networks. *Current
 Biology* 26:75-79
description: # The socioecology of elephants: analysis of the processes creating
 multitiered social structures
 [https://doi.org/10.5061/dryad.djh9w0w6f](https://doi.org/10.5061/dryad.djh9w0w6f) ## Description of the data and file structure Three files containing distance matrices (1 - simple association indices) of adult female elephants. The three matrices represent different time periods: June 1998 - May 2001, June 2001 - August 2004, June 2012 - July 2014. These matrices were analyzed using clustering algorithms to derive social networks and social trees capturing relationships between individual elephants. These data can be used to assess social network structure and node level social network metrics of wild African elephants. ### Description of the data The data provided here are association distance matrices (i.e. 1 - simple ratio association index values) for successive, multi-year time periods. Data are presented in matrices where individual identity codes are listed across column 1 elements and row 1 elements in the matrices. Individual identify codes are unique letter number combinations assigned to every identified elephant in the population (e.g., R1 - S92.94). NA values represent elements for which no data exit because the two individuals were not available to interact during the time period due to the death of one individual before the recruitment of the other. Association distance values were derived from observations collected as described below. The majority of observations were collected by observers recording all individuals encountered along one of four set routes travelled daily within the study area. Routes followed existing roads running the length of the Samburu and Buffalo Spring National Reserves in northern Kenya, both to the north and south of the Ewaso N'giro River. Routes 1 and 2 were within 500 m of either riverbank and routes 3 and 4 were located approximately 5 km from the river on either side. Observations of elephant aggregations during nontransect movements in the study area (opportunistic sampling) were also recorded and used in this study. All observations were recorded following the same protocol. Once elephants were spotted, observers approached to within 100 m or less of the aggregation and recorded the following data: (1) identity of individuals present; (2) accuracy of the observation (recorded in categories: (a) 100% identification of all individuals; (b) identification of all breeding females and males excluding calves; and (c) incomplete identification); (3) location of aggregation; and (4) the date, time, observer name and route name. The observer stayed with the aggregation until all individuals were recognized, unless thick vegetation did not allow a complete accounting. ### Description of the file strucutre Each file represents the distance matrices derived from data collected over the successive years in the matrix name: June 1998 - May 2001 June 2001 - August 2004 June 2012 - June 2014 Association distance matrices are organized where the name of each individual elephant inhabits the elements of Row 1 and Column 1, and successive elements in the matrix represent the association distance of the corresponding row 1 and column 1 constituents. NA values represent pairs that did not overlap during the data sampled time period (e.g., individual 1 died before individual 2 was recruited into the sample). ## Sharing/Access information Please contact George Wittemyer [g.wittemyer@colostate.edu ](mailto:g.wittemyer@colostate.e)for additional information.