In a 6.5 year study, marine biologists led by Dr Elizabeth Murdoch Titcomb from the Harbor Branch Oceanographic Institute at Florida Atlantic University took a closer look at the interactions between bottlenose dolphins (Tursiops truncatus) in the Indian River Lagoon, Florida, and discovered how the dolphins mingle and with whom they spend their time.

Through intensive photo-identification surveys, Dr Titcomb and co-authors were able to learn about the association patterns as well as movement behavior and habitat preferences of 185 individual dolphins.

The scientists found that the Indian River Lagoon (IRL) population was highly differentiated and organized into six distinct social communities that tended to occupy discrete core areas along the north-south axis of the lagoon system.

They also found that individual dolphins exhibited both preference and avoidance behavior – so just like humans, they have dolphins they like and associate with and ones they avoid.

“One of the more unique aspects of our study was the discovery that the physical dimensions of the habitat, the long, narrow lagoon system itself, influenced the spatial and temporal dynamics of dolphin association patterns,” said Dr Titcomb, lead author on the paper in the journal Marine Mammal Science.

“For example, communities that occupy the narrowest stretches of IRL have the most compact social networks, similar to humans who live in small towns and have fewer people with whom to interact.”

In addition to providing a unique glimpse into dolphin societies, the study provides important insight and knowledge on how dolphins organize themselves, who they interact with and who they avoid, as well as when and where.

It also gives scientists and resource managers the roadmap needed to understand how dolphin populations perceive and use their environment, and how social networks will influence information transfer and potentially breeding behavior and disease transmission.

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Elizabeth Murdoch Titcomb et al. Social communities and spatiotemporal dynamics of association patterns in estuarine bottlenose dolphins. Marine Mammal Science, published online April 03, 2015; doi: 10.1111/mms.12222