Whales and Dolphins Interact More Often Than Scientists Thought, Engaging in Mutual Play, Study Suggests

Researchers analyzed nearly 200 videos and photographs documenting interactions between the various kinds of cetaceans

A bottlenose dolphin is seen “bow riding,” or swimming just in front of a humpback whale, potentially getting a boost from the wave created by the larger mammal. Roving Media via Griffith University

Dolphins and whales interact with each other more often than previously thought, according to a recent study that examined images and footage of the marine mammals interacting. The scientists classified one quarter of these interactions as mutual and positive.A duo of researchers analyzed 199 independent whale-dolphin interactions sourced from photos and videos shared on social media platforms. The events in the posts spanned 17 countries—though most were from the United States and Australia—and took place across two decades. Researchers also reviewed two videos from camera tags attached to two humpback whales.

From these records, the team identified interactions between six whale and 13 dolphin species, showing the animals seemingly playing and swimming with each other. The findings were published in the journal Discover Animals last week.

Fun fact: Dolphins versus whales

Technically, dolphins are classified as toothed whales, putting them as the same taxonomic category as porpoises, beluga whales and sperm whales. Other whales, such as humpbacks, are known as baleen whales. Killer whales fall into the toothed whales group—and they’re actually the largest members of the dolphin family.

The scientists found that most of these interactions were initiated by dolphins approaching the whales, usually humpbacks. In 80 percent of them, the dolphins were seen swimming near the whales’ heads, a form of one-sided play that also helps dolphins save energy while traveling. Sometimes, the dolphins would even nudge or rub the whales.

Sometimes, the whales responded to these approaches. Humpback whales tended to move a pectoral fin toward the dolphins or expose their bellies, gray whales would roll and southern right whales would slap the water with their pectoral fins. These behaviors are typically associated with socialization, courtship or communication.

In humpback whales, specifically, “at least one-third of the interactions we classified as positive, with the humpback whales actually seeking out swimming towards the dolphins,” says Olaf Meynecke, the study’s lead author and a marine biologist at Griffith University in Australia, to National Geographic. Signs of aggression from humpback whales were rare.

Dolphins have been observed around whales before, but the behavior has “historically been looked at as the dolphins playing with this big thing in the ocean,” says Thea Taylor, the managing director of the Sussex Dolphin Project who was not involved in the research, to National Geographic. “But there hasn’t been much record of the whales interacting and playing back.”

In fact, scientists previously observed a humpback using its head to lift a bottlenose dolphin out of the water in 2004, and researchers suggested the whale was showcasing caregiving behavior—and that such interactions were rare. But this new study shows interactions between the animals are much more wide-ranging than that.

Scientists aren’t yet sure what draws the mammals together. It could be their close evolutionary relationship and the fact that they share similar behaviors. Still, researchers say the findings could have important implications for whale and dolphin conservation.

“These are highly intelligent animals, and just like humans, they need creative times, they need times when their brain is in a relaxed mode,” says Meynecke to James Taylor at the Australian Broadcasting Corporation. Interactions between these animals could help them live longer and better lives, he explains.“Play behavior in the events described in our study may facilitate an individual’s ability to cultivate relationships, offer sensory stimulation and contribute to the overall well-being,” he adds.

Wally Franklin, a marine scientist at the Oceania Project who was not involved in the study, tells the Australian Broadcasting Corporation that over his decades-long career observing humpback whales, he has often seen dolphins interacting with them in ways that appear playful. “There’s no doubt that the whales respond in a very positive fashion to the presence of the dolphins,” he says.

The study also highlights the potential for using new technologies and citizen science to study animals, Meynecke notes in an article for the Conversation. Despite the limitations of social media, collecting data through these platforms allowed the researchers to uncover interactions that traditional surveys might have missed, he writes.Future work could incorporate acoustic recordings and longer observation periods to “further unravel the motivations and meanings behind these fascinating encounters,” per the Conversation.

Sara Hashemi – Daily Correspondent