Are Dolphins Trying to Communicate Across the Species Barrier?

Every time I see a row of seaside lampposts, each with a single seagull perched on it, I wonder: Do those birds think we built the highway system for them? I suspect the answer's yes. Each species of animal (like people, most of the time) seems to see the world as if it were made for them alone. Other species are mere objects: this one would be good for lunch, that one's an information source (think canary in the coal mine), these others are just obstacles in our way (think geese in the engines). This paper in the current issue of Ethology reports an interesting exception to the rule: Two species of dolphins which, when they swim together, replace their usual vocalizations with sounds that seem to fall halfway between their separate "languages."


Laura May-Collado's paper, which describes recordings made at the Gandoca-Manzanillo Wildlife Refuge off the coast of Costa Rica, can't spell out whether the "intermediate" sounds are coming from both bottlenose and Guyana dolphins when the two types swim together. (Her equipment, as reported here, recorded the changed vocalizations, but didn't have a way of identifying which particular animals were making the sounds). But Guyana dolphins are smaller than bottlenose and get pushed around when the two species swim together, so, May-Collado speculated in a BBC interview, perhaps the Guyanas are trying to ward off or threaten the bullies by coming as close as they can to making sounds the others recognize.

Other scenarios are possible, though. Perhaps both species are making the compromise whistles, whose range and frequency fall between the characteristics of the calls they make when they're with their own kind. Or perhaps the Guyana, when "talking" to each other about the strangers, imitate them.

None of this is proof that the dolphins are aware that another species consists of creatures that are just as real as they are. But it does look to be an interesting exception to the Earth's usual species solipsism.

May-Collado, L. (2010). Changes in Whistle Structure of Two Dolphin Species During Interspecific Associations Ethology, 116 (11), 1065-1074 DOI: 10.1111/j.1439-0310.2010.01828.x

Related Articles

Scientists discover what caused the worst mass extinction ever

How a cataclysm worse than what killed the dinosaurs destroyed 90 percent of all life on Earth.

Credit: Ron Miller
Surprising Science

While the demise of the dinosaurs gets more attention as far as mass extinctions go, an even more disastrous event called "the Great Dying” or the “End-Permian Extinction” happened on Earth prior to that. Now scientists discovered how this cataclysm, which took place about 250 million years ago, managed to kill off more than 90 percent of all life on the planet.

Keep reading Show less

Why we're so self-critical of ourselves after meeting someone new

A new study discovers the “liking gap” — the difference between how we view others we’re meeting for the first time, and the way we think they’re seeing us.

New acquaintances probably like you more than you think. (Photo by Simone Joyner/Getty Images)
Surprising Science

We tend to be defensive socially. When we meet new people, we’re often concerned with how we’re coming off. Our anxiety causes us to be so concerned with the impression we’re creating that we fail to notice that the same is true of the other person as well. A new study led by Erica J. Boothby, published on September 5 in Psychological Science, reveals how people tend to like us more in first encounters than we’d ever suspect.

Keep reading Show less

NASA launches ICESat-2 into orbit to track ice changes in Antarctica and Greenland

Using advanced laser technology, scientists at NASA will track global changes in ice with greater accuracy.

Firing three pairs of laser beams 10,000 times per second, the ICESat-2 satellite will measure how long it takes for faint reflections to bounce back from ground and sea ice, allowing scientists to measure the thickness, elevation and extent of global ice
popular

Leaving from Vandenberg Air Force base in California this coming Saturday, at 8:46 a.m. ET, the Ice, Cloud, and Land Elevation Satellite-2 — or, the "ICESat-2" — is perched atop a United Launch Alliance Delta II rocket, and when it assumes its orbit, it will study ice layers at Earth's poles, using its only payload, the Advance Topographic Laser Altimeter System (ATLAS).

Keep reading Show less