Dolphins are unquestionably highly charismatic animals. They have unique and sophisticated communication skills and also are known to use tools, including sponges to protect their sensitive beaks, when foraging for food.
During the past two weeks I came across two extremely interesting articles about these crafty cetaceans. The first, titled "Dolphin whistle instantly translated by computer" by Hal Hodson, considers the possibility that dolphins are able to whistle the same words we use to denote an object. The print version of the latter essay is called "Decoding dolphin." The second, called "Cultural transmission of tool use combined with habitat specializations leads to fine-scale genetic structure in bottlenose dolphins" by Anna Kopps of the University of New South Wales and her colleagues, focuses on their use of protective sponges during foraging and its effect on the genetic structure of dolphin populations.
Say what? Did you really whistle seaweed?
Denise Herzing is well known for her and her team's long-term field research on Atlantic spotted dolphins. Among many aspects of the amazing lives of dolphins, she has long been interested in dolphin communication and whether or not they and other animals use language to communicate with one another or can use language to communicate with us.
While it's too early to know for sure, there is compelling evidence that some animals are language users (see, for example, a brief review of the research by Dr. Con Slobochikoff on prairie dogs). I found Hal Hodson's essay called "Decoding dolphin" to be an extremely interesting, stimulating, and easy read. To wit, and I encourage you to take a few minutes to read it, Mr. Hodson begins: "IT was late August 2013 and Denise Herzing was swimming in the Caribbean. The dolphin pod she had been tracking for the past 25 years was playing around her boat. Suddenly, she heard one of them say, 'Sargassum'". And, what did Dr. Herzing exclaim? "'I was like whoa! We have a match. I was stunned.'" Dr. Herzing "was wearing a prototype dolphin translator called Cetacean Hearing and Telemetry (CHAT) and it had just translated a live dolphin whistle for the first time." So, "When the computer picked up the sargassum whistle, Herzing heard her own recorded voice saying the word into her ear." I, too, would have been stunned and I can't wait for more research in this fascinating area of study.
Perhaps we are not the only animals who use language. Dr. Terrence Deacon, a neuroscientist at the University of California, Berkeley, who also is an expert in animal communication, notes, "I don't see a fundamental white line that distinguishes us from other animals." Only time and research will tell if we're alone in the language arena. For now it's a good idea to keep the door wide open.
Cultural hitchhiking: Was there a "sponging Eve"?
An informative summary of the research on the genetics of tool use in dolphins living in Shark Bay in Western Australia can be found in an article called "Cultural hitchhiking: How social behavior can affect genetic makeup in dolphins." It turns out that the culturally transmitted use of sponges—called vertical social transmission—can actually "shape the genetic makeup" of wild dolphins. Dolphins, who live deep in the bay, show mitochondrial DNA (mtDNA) types called Haplotype E or Haplotype F that are inherited solely from the mother, whereas non-sponging dolphins who live in shallower water mainly show Haplotype H. All of the 22 sponging dolphins who were observed turned out to be members of one matriline and were Haplotype E.
This novel and significant discovery demonstrates a strong correlation between haplotype and habitat. According to Dr. Kopps, "Our research shows that social learning should be considered as a possible factor that shapes the genetic structure of a wild animal population." She also notes, "For humans we have known for a long time that culture is an important factor in shaping our genetics. Now we have shown for the first time that a socially transmitted behaviour like tool use can also lead to different genetic characteristics within a single animal population, depending on which habitat they live in." This is one of the first demonstrations of what is called "cultural hitchhiking" in nonhuman animals.
What an exciting time it is to study the behavior of nonhuman animals. Stay tuned for more on their fascinating lives.
Marc Bekoff's latest books are Jasper's story: Saving moon bears (with Jill Robinson; see also), Ignoring nature no more: The case for compassionate conservation (see also), and Why dogs hump and bees get depressed (see also). Rewilding our hearts: Building pathways of compassion and coexistence will be published fall 2014.