Dolphin Tales

When two groups of like animals attempt to co-habitat the same territory, it can often lead to a battle.

But that wasn’t the case for two groups of dolphins who spent the last few years living in the same waters, according to a study by Denise Herzing, Ph.D., an affiliate professor in the FAU Charles E. Schmidt College of Science, and her team, recently published in the journal Marine Mammal Science.

“This was a unique opportunity to study a large-scale immigration event. It’s like a natural experiment,” said Herzing, who is also the research director of the Wild Dolphin Project (WDP).

In 2013, Herzing said, 52 wild Atlantic spotted dolphins left their home off Grand Bahama Island and moved 100 miles south to Bimini, where an existing community of resident dolphins already lived.

From 2013 to 2020, Herzing recorded 206 total dolphin encounters off Bimini and collected data that included individuals present and behaviors, such as fighting, playing, mating, feeding or traveling. Sometimes, groups were just the resident Bimini animals, other times, just the immigrants from Grand Bahama — and sometimes, the groups were mixed.

Using a software that analyzes animal social structure using individual identifications (the analysis which was led by co-author Cindy Elliser, Ph.D., an FAU alumna) the scientists found that while the communities were integrating, there were still strong bonds within the original communities. For the first three years, there was little interaction and two distinct social clusters delineated by residency status. Over time however, interactions between the two groups increased and Herzing and others even witnessed courtship and other friendly behaviors.

“Although this isn’t necessarily surprising — you won’t just leave the good friends you have had over many years — it is an interesting mixture of old and new relationships that is shaping the social structure and showing that both new and old relationships can be maintained and create a new, different community,” Elliser said.

This was a unique study showing the full integration of a displaced spotted dolphin community, Herzing said. “After watching their gradual integration, this paper describes their full integration over seven years, males and females, young and old,” she said. “It shows us the importance of long-term research, especially now that climate change is impacting ocean habitats.”