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Index of Subjects
Index of Subjects --Apple-Mail-192-513914466 Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Content-Transfer-Encoding: 7bit Hi Steve, On 22-Dec-11, at 2:24 AM, Stephen R. Shaw wrote: > These are some intriguing examples, wish I had prizes to offer. > > Chris' dolphin example is fascinating, and might be another case of > learning for an extra or easier reward, based on a much older > cooperative behaviour to school fish in order to make them easier to > catch for the pod, that other cetaceans also exhibit. You'd then > perhaps ask who was actually training whom -- the humans presumably > learned something from the dolphins, who in a real sense were the > initial teachers. I suppose that if it were recent (is known for 6 > centuries 'recent'?), the new behaviour with humans could be > socially transmitted through generations by the local dolphin > society/pod, not necessarily through genetic change. In the Banc d'Arguin region of Mauritania the Sahara meets the Atlantic. The slope of the land is very gradual so there are very wide expanses of shallow water. The Imraguen fishermen stand on dune crests and look out over the ocean. From this vantage they can see passing schools of mullet through subtle changes in the hue of the water, however, the fish are far enough away from the coast that the fisherman couldn't get out to them with their nets. Whether the dolphins have an acoustic way of perceiving the mullet schools or not is unknown, but they cannot, of course, visually scan a wide area of the ocean. When the fishermen see a passing school of mullet one of them goes down to the water's edge and begins pounding it with a log, making a low-frequency sound they presumably travels a long distance. Some ten minutes later dolphins begin to appear in the distance. Numbers vary from a half dozen to a dozen and can consist of three different species (I'm not sure if there are mixed groups of species). The dolphins form a crescent and herd the fish towards the shore. They are met by a crescent of advancing fisherman who wade out into the water with their nets. The two groups meet and the fishermen encircle the mullet. Mullet are caught in these gill nets while the dolphins swim in and out of the "enclosure" catching fish that have been concentrated and trapped by the nets. After everyone has caught/eaten their fill the dolphins swim away and the fishermen wade ashore with their catch. This cooperative behaviour has been know since at least the 15th century (and who know who long before that) when it was documented by traveling Portuguese fishermen. The cooperative behavior is clearly beneficial to both groups, and once in existence, it's easy to understand how new generations of both fisherman and dolphins continue to learn what to do. But try and imagine how such a cooperative arrangement might have come into being. :~> For those interested in more detail, the investigator whom I met who documented this cooperative behavior in great detail was Rene Guy Busnel who published: Busnel, R.G. 1973. Symbiotic relationship between man and dolphins. Transactions of the New York Academy of Sciences. Ser. 11, 35(2): 112-131. I unfortunately cannot find a copy of this paper available online, however, Pryor et al. (1990) documents a similar working arrangement between people and dolphins in Brazil and looks at historical accounts of such co-evolved fishing practices going back to Pliny the Elder (A.D. 23-79). Pryor, K., Lindbergh, J., Lindbergh, S., and Milano R.1990. A dolphin- human fishing cooperative in Brazil. MArine Mammal Science 6(1): 11-82. http://reachingtheanimalmind.com/pdfs/ch_12/ch_12_pdf_01.pdf Cheers! Chris Christopher Majka <c.majka@ns.sympatico.ca> | Halifax, Nova Scotia, Canada * Research Associate: Nova Scotia Museum | http://museum.gov.ns.ca/mnh/research-asfr.htm * Review Editor: The Coleopterists Bulletin | http://www.coleopsoc.org/ * Subject Editor: ZooKeys | http://pensoftonline.net/zookeys/index.php/journal/index * Review Editor: Zootaxa | http://www.mapress.com/zootaxa/taxa/Coleoptera.html * Associate Editor: Journal of the Acadian Entomological Society | http://www.acadianes.org/journal.html * Editor: Atlantic Canada Coleoptera | http://www.chebucto.ns.ca/Environment/NHR/PDF/index.html * Editor: Bugguide, Coleoptera http://bugguide.net Whenever I hear of the capture of rare beetles, I feel like an old war- horse at the sound of a trumpet. - Charles Darwin --Apple-Mail-192-513914466 Content-Type: text/html; charset=US-ASCII Content-Transfer-Encoding: quoted-printable <html><body style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; = -webkit-line-break: after-white-space; ">Hi Steve,<div><br><div><div>On = 22-Dec-11, at 2:24 AM, Stephen R. Shaw wrote:</div><br = class=3D"Apple-interchange-newline"><blockquote type=3D"cite"><div>These = are some intriguing examples, wish I had prizes to offer.<br><br>Chris' = dolphin example is fascinating, and might be another case of learning = for an extra or easier reward, based on a much older cooperative = behaviour to school fish in order to make them easier to catch for the = pod, that other cetaceans also exhibit. You'd then perhaps ask who = was actually training whom -- the humans presumably learned something = from the dolphins, who in a real sense were the initial teachers. I = suppose that if it were recent (is known for 6 centuries 'recent'?), the = new behaviour with humans could be socially transmitted through = generations by the local dolphin society/pod, not necessarily through = genetic change.<br></div></blockquote></div><br></div><div>In = the Banc d'Arguin region of Mauritania the Sahara meets the = Atlantic. The slope of the land is very gradual so there are very wide = expanses of shallow water. The Imraguen fishermen stand on dune = crests and look out over the ocean. =46rom this vantage they can see = passing schools of mullet through subtle changes in the hue of the = water, however, the fish are far enough away from the coast that = the fisherman couldn't get out to them with their nets. Whether the = dolphins have an acoustic way of perceiving the mullet schools or not is = unknown, but they cannot, of course, visually scan a wide area of the = ocean.</div><div><br></div><div>When the fishermen see a passing school = of mullet one of them goes down to the water's edge and begins pounding =