A new study draws fresh attention to how whales and dolphins meet and mingle during their journeys. Researchers investigated hundreds of public, tourist, and scientific videos and images, including recordings from whale-watching tour providers and social media platforms. According to National Geographic, researchers analyzed videos and photographs from 199 independent whale-dolphin interaction events involving 19 species across 17 locations worldwide, and found that about one-quarter of encounters were possibly positive, with more than one-third classified as positive or possible social play.
For humpback whales, about one-third of the events appeared positive. “The humpback whales were rolling from side to side, undertaking belly presentation and other behaviors that are associated with courtship or friendly socializing,” said Meynecke. “Whales also strategically moved slowly in the direction of the dolphins with their head and rostrum,” said Meynecke.
The research team cataloged each encounter by species, date and time, location, number of animals, age class, and the dolphins’ positions relative to whale body parts such as head, flank, and tail fluke. They also categorized behaviors such as rolling, tail slaps, bow riding, and rubbing. In total, the documented interactions included 425 baleen whales from six species, with humpbacks making up 68% of interactions, gray whales 16%, and fin whales 7%. On the dolphin side, bottlenose dolphins made up 51% of observations, common dolphins 17%, and Pacific white-sided dolphins 15%. An estimated 1,570 dolphins were observed. Adults formed the largest share of interactions; a dolphin calf was present in 53 events, a whale calf in 44, and both calves in 21.
Based on videos, dolphins initiated most interactions through bow riding, swimming in formation, or touching whales. In 80% of encounters, dolphins swam close to whale heads, often engaging in one-sided play by bow riding. “It clearly gives them pleasure to use the whale’s pressure wave, similar to how humans do when surfing,” said Meynecke, according to Stern. “The assumption is that the dolphins stay within sight of the whales to be seen by them. The animals can already perceive each other through sounds, but visual perception seemed to be of interest as well,” said Meynecke.
Camera tags attached to humpbacks offered an underwater perspective. Two videos showed bottlenose dolphins following humpbacks at the surface and down to the sea floor, maintaining eye contact. Two additional tagged encounters captured close approaches and touches to whale heads. Most interactions did not show avoidance behavior, suggesting intentional, possibly social, engagement.
Not all contact was positive. “While social play is cooperative and reciprocal, there is also one-sided play or interaction, with only one participant perceiving the interaction as playful, as seen in cases of teasing or harassment by dolphins during feeding events,” said Meynecke. In times of food competition, whales sometimes signaled with tail slaps to keep distance. Physical percussive behaviors that could indicate aggressive responses toward dolphins were least observed for humpbacks; humpbacks exhibited 18 tail slaps and no head slaps. Southern right whales displayed five pectoral slaps across 10 events, while gray whales often rolled in response to dolphins, with 56 counts recorded.
A notable 2004 interaction in Hawaii showed a humpback repeatedly lifting a bottlenose dolphin on its head. Researchers suggested such close contact was likely rare and may have been related to caregiving. Dolphins tended to remain nearby during disputes among whales or when calves were present, observing closely without intervening. Even when many encounters were neutral, whales sometimes reacted positively to their curious companions.
Motives behind these encounters remained unsettled. “It could actually be entertainment. Just like with humans, the brain, especially in intelligent beings, needs phases of creativity,” said Meynecke. “But there hadn’t been much recording of the whales interacting and playing,” said Thea Taylor, director of the Sussex Dolphin Project in England. “Having the opportunity to document these observations and observe some of the behavioral patterns like bow riding by dolphins and close touches was intriguing,” said co-author and master’s graduate Olivia Crawley.
Researchers drew from Facebook, YouTube, and Instagram, along with citizen-contributed footage and drone video. The approach offered diverse behavioral data that traditional surveys might miss but carried limitations such as geographic and observer bias. Each entry was reviewed to identify species, validate interactions, and categorize behaviors. “Behavioral studies of marine mammals such as these provided insight into their complex social structures, played a crucial role in enhancing our understanding of marine ecosystems, and the interactions among marine species,” said Meynecke.