Captive Dolphins 'Look Forward' to Play With Humans, Like Pavlov's Dogs

A trainer greets a captive dolphin. A new study finds that dolphins will peer above the water when they are expecting human interaction more than when they are expecting toys or a control. ADRIAN CATU/AFP/Getty Images

Do dolphins enjoy playing with human companions? No one knows for sure, but a new study indicates that captive bottlenose dolphins react when they know they are going to play with familiar trainers, moreso than they do when they expect to play with toys or when they expect to be left alone.

For a study published recently in the journal Applied Animal Behavior Science, researchers tested captive bottlenose dolphins in French theme park Parc Astérix. They played a different sound before offering the animals different stimuli, including adding toys to the water, bringing a trainer to play with them, and a control, where they left the dolphins to do as they wished.

The researchers found that when the dolphins were presented with the sound indicating they would get to interact with people, they would "look forward" to the interaction more than being offered toys or the control group, according to the study. The researchers came to this conclusion because the animals would engage in "spy-hopping," in which they would poke their heads out of the water to see what's happening. According to the study, this "indicates motivation to participate in certain events."

"We've seen this same thing in other zoo animals and in farm animals," Isabella Clegg. lead researcher on the study and animal behaviorologist at Université Paris 13 in France, told BBC. "Better human-animal bonds equals better welfare."

This study relies on "classical conditioning," in which when a person or animal is trained to associate one thing with something else outside their control. The most famous example of this is Pavlov's dogs, in which Russian physiologist Ivan Pavlov taught dogs to associate the sound of a bell with being fed. It's a common technique in the study of animal behavior to try to understand if an animal will seek a certain stimulus and the sight, sound or smell associated with it.

Some news outlets have reported that this new study "measures happiness" in dolphins. However, according to David Lusseau, professor of behavioral biology at the University of Aberdeen in Scotland, who has been working with bottlenose dolphins for around 25 years, "Happiness has nothing at all to do with the study."

"When they're spy-hopping they're trying to look up and see what's happening," Lusseau told Newsweek. "It doesn't tell us actually about how the dolphins feel about the interaction, it doesn't mean they are happy."