Diversity and Consequences of Social Network Structure in Toothed Whales

Michael N Weiss,Samuel Ellis,Darren P Croft

doi:10.3389/fmars.2021.688842

Michael N Weiss, Samuel Ellis + Show 1 more

Open Access

https://doi.org/10.3389/fmars.2021.688842

Copy DOI

Abstract

Toothed whales (suborder Odontoceti) are highly social, large brained mammals with diverse social systems. In recent decades, a large body of work has begun investigating these dynamic, complex societies using a common set of analytical tools: social network analysis. The application of social network theory to toothed whales enables insight into the factors that underlie variation in social structure in this taxon, and the consequences of these structures for survival, reproduction, disease transmission, and culture. Here, we perform a systematic review of the literature regarding toothed whale social networks to identify broad patterns of social network structure across species, common drivers of individual social position, and the consequences of network structure for individuals and populations. We also identify key knowledge gaps and areas ripe for future research. We recommend that future studies attempt to expand the taxonomic breadth and focus on standardizing methods and reporting as much as possible to allow for comparative analyses to test evolutionary hypotheses. Furthermore, social networks analysis may provide key insights into population dynamics as indicators of population health, predictors of disease risk, and as direct drivers of survival and reproduction.

Highlights

The structure of social interactions between individuals is a fundamental feature of animal populations, with far reaching consequences (Kurvers et al, 2014)
We found 4 studies on members of the family Ziphiidae conducted on 4 species
There are countless features of social network structure that could be examined. We focus on those aspects of social network topology which are both commonly measured in toothed whale studies, and are potentially relevant to the biology of these animals: social modularity and social differentiation, the role of kinship, sex, and behavioural phenotypes in shaping these networks, and what factors correlate with variation in social centrality

Summary

INTRODUCTION

The structure of social interactions between individuals is a fundamental feature of animal populations, with far reaching consequences (Kurvers et al, 2014). While not addressed directly by studies in our review, sperm whales are known to exhibit extreme spatial segregation between males and females (Whitehead, 2003) This has likely not been addressed directly using social network methods due to the extreme degree of segregation in this species meaning that individualized relationships need not be measured to identify sexual segregation. Several studies report that bottlenose dolphins interacting with fisheries and aquaculture preferentially associate with each other (Chilvers and Corkeron, 2001; Kovacs et al, 2017; Genov et al, 2019; Machado et al, 2019; Methion and Diaz Lopez, 2020) This pattern is present in Strait of Gibraltar killer whales, where social community structure perfectly correlates with degree of interaction with the local tuna fishery (Esteban et al, 2016a). Future research focusing on applying new methods, studying less well understood species, and applying this knowledge directly to conservation problems may provide important components of continued efforts to understand and conserve toothed whale populations worldwide

DATA AVAILABILITY STATEMENT

Findings

CONCLUSION