A new study from the Hubbs-SeaWorld Research Institute has found that captive orcas kept with bottlenose dolphins adopt the signature clicks and whistles of their tank mates. But some scientists question claims made in the paper that this knowledge can benefit endangered orca populations in the wild.
The study, which will appear in the next issue of Journal of the Acoustical Society of America,reported that captive killer whales exhibit similar vocal “repertoires” as bottlenose dolphins after spending time with them, suggesting considerable “vocal plasticity” and a desire for “vocal conformity” in their social environment.
In other words, they just want to fit in.
The authors analyzed vocal recordings of captive bottlenose dolphins and killer whales. Three of the orcas were kept with dolphins: two at SeaWorld parks and one at Six Flags, Discovery Kingdom. That orca is presumably Shouka, who was transferred to SeaWorld San Diego in 2012, partly because of protests that her only companions for several years were dolphins.
Their vocal repertoire turned out to be far more “dolphin like” than that of seven killer whales who were only kept with other orcas, the study found.
Killer whales, while members of the dolphin family, communicate differently from most dolphin species. Their vocalizations are dominated by “pulsed calls,” complex bursts and tones that have been compared to a squeaky door. Bottlenose dolphins, on the other hand, rely on a system of clicks and “terminal buzzes” to communicate, according to the study.
Killer whales not exposed to dolphins “produced few to no click trains and never emitted terminal buzzes,” the study said. The three that spent time with bottlenose dolphins produced both clicks and buzzes and fewer pulsed calls.
“These differences provided evidence for contextual learning," the researchers wrote. “One killer whale spontaneously learned to produce artificial chirps taught to dolphins.”
So what does this mean in practical terms?
For one, activists say that water parks and aquariums could use the data to justify keeping orcas without a same-species companion, which is permissible under the federal Animal Welfare Act, as long as the animals are members of the same animal family.
But activists consider that a loophole that permits whales such as Lolita, at the Miami SeaQuarium, to live only with dolphins.
Meanwhile, the study’s authors said their findings can benefit wild killer whales.
“Recent studies (show) that killer whales might be able to learn new repertoires that could allow them to integrate with other groups,” the paper noted. “The question is important because the fates of killer whales in populations reduced or displaced by environmental change will be determined in part by their ability to socialize with new groups, and thus by the factors that control vocal plasticity.”
But as the study pointed out, scientists have already learned that different orca pods can mimic parts of each other's dialects during social interactions.
So how does it help conservation efforts to know that captive orcas learn how to mimic captive dolphins?
Hubbs-SeaWorld (which receives funding but is independent from the entertainment company) did not respond to an interview request. Officials at the National Oceanic and Atmospheric Administration could not find an expert to provide comment at press time.
Naomi Rose, a leading orca researcher and a marine mammal scientist at the Animal Welfare Institute, was puzzled by the claim.
“Maybe they’re saying that as the populations decline, they might find being able to change their vocalization patterns helpful?” Rose wrote in an email. “I’m not sure why this would follow.”
“Personally,” Rose added, “I think knowing how whales and dolphins communicate, with each other and with other populations and species, is fascinating, but it’s not essential to understand in order to protect them from the many threats they are facing.”
