Research from the Sky: Drones and Dolphins

We’ve got new research out, in the journal Southeastern Naturalist

Aggression between spotted dolphin and bottlenose dolphin males

Aggression between spotted dolphin and bottlenose dolphin males

Our team analyzed drone video footage to help document the first-known case, to our knowledge, of two species of dolphins interacting off the Southeast coast of Florida, which highlights the value of drones in helping scientists collect previously-unavailable data, including habitat details, body size and health information. 

Whales and dolphins, known as cetaceans, often form mixed-species groups, for benefits that include defense from predators, better success when hunting fish, and social interactions. Mixed-species groups are common around the world, yet gaps remain in why and how they form, said Denise Herzing, Ph.D., research director of the Wild Dolphin Project (WDP). She has studied the interactions between two species of dolphins – Atlantic spotted dolphins and common bottlenose dolphins – that coexist in the Bahamas. 

Dueling Dolphins

For more than 35 years, gaining a deeper understanding of the two species’ aggressive encounters and why they occur has been the subject of many of WDP’s studies. For instance, it’s hypothesized by Herzing that fighting between the two males of each species is a means to prevent hybridization, since they do not need to fight over food or space. 

“During our Florida surveys we have seen spotted dolphins, and bottlenose dolphins, but never together,” she said.

Dolphins and Drones

But, that all changed when local manta ray research, Jessica Pate, lead scientist of the Florida Manta Project, found both species interacting together when surveying for mantas along the Florida coast. From the footage, it looked like social behavior, courtship or play (which can be hard to distinguish). Jessica shared the footage with us, which we then analyzed. In that way, this paper highlights the value and importance of collaborative work among scientists, said Herzing.

Initially, Jessica found 23 bottlenose dolphins and 1 spotted dolphin via drone. The bottlenose were chasing and hunting fish at the surface. The spotted dolphin tried to engage the bottlenose dolphins by swimming ahead in an inverted position, thought to often indicate a solicitation and by occasionally tail-slapping the water surface, which is often interpreted as an attention-getting signal. The spotted dolphin was never seen feeding.

The Atlantic Spotted Dolphin tail-slapping the water surface in front of the 3 Common Bottlenose Dolphins. Images captured from drone footage off Florida coast on 11 September 2020.

Thus, Herzing and the co-authors, suspect this interaction was for social reasons. More data on mixed-species groups in Florida are needed to answer why these groups form and their functions, she said, especially considering the impact on cetaceans with changing environmental conditions. “It’s important, as it is in all field studies, to have a baseline of information from which we can compare new observations.”