Could relatedness help explain why individuals lead in bottlenose dolphin groups?

PLoS One. 2013;8(3):e58162. doi: 10.1371/journal.pone.0058162. Epub 2013 Mar 13.


In many species, particular individuals consistently lead group travel. While benefits to followers often are relatively obvious, including access to resources, benefits to leaders are often less obvious. This is especially true for species that feed on patchy mobile resources where all group members may locate prey simultaneously and food intake likely decreases with increasing group size. Leaders in highly complex habitats, however, could provide access to foraging resources for less informed relatives, thereby gaining indirect benefits by helping kin. Recently, leadership has been documented in a population of bottlenose dolphins (Tursiops truncatus) where direct benefits to leaders appear unlikely. To test whether leaders could benefit indirectly we examined relatedness between leader-follower pairs and compared these levels to pairs who associated but did not have leader-follower relationship (neither ever led the other). We found the average relatedness value for leader-follower pairs was greater than expected based on chance. The same was not found when examining non leader-follower pairs. Additionally, relatedness for leader-follower pairs was positively correlated with association index values, but no correlation was found for this measure in non leader-follower pairs. Interestingly, haplotypes were not frequently shared between leader-follower pairs (25%). Together, these results suggest that bottlenose dolphin leaders have the opportunity to gain indirect benefits by leading relatives. These findings provide a potential mechanism for the maintenance of leadership in a highly dynamic fission-fusion population with few obvious direct benefits to leaders.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Behavior, Animal*
  • Bottle-Nosed Dolphin* / genetics
  • Ecosystem
  • Female
  • Geography
  • Leadership*
  • Male
  • Microsatellite Repeats
  • Multilocus Sequence Typing
  • Social Behavior*

Grant support

This research was supported through funding from Sigma Xi, Project Aware, and Harbor Branch Oceanographic Institute Protect Wild Dolphins Grant. J Lewis was supported while conducting this research and writing this manuscript by Florida International University’s Dissertation Acquisition and Dissertation Year Fellowships. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.